Merge branch 'dev' into idf_no_heap_alloc_url

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Co-authored-by: J. Nick Koston <nick@koston.org>

.clang-tidy.hash

@@ -1 +1 @@
-d272a88e8ca28ae9340a9a03295a566432a52cb696501908f57764475bf7ca65
+d15ae81646ac0ee76b2586716fe697f187281523ee6db566aed26542a9f98d1a

.claude/skills/pr-workflow/SKILL.md

@@ -0,0 +1,96 @@
+---
+name: pr-workflow
+description: Create pull requests for esphome. Use when creating PRs, submitting changes, or preparing contributions.
+allowed-tools: Read, Bash, Glob, Grep
+---
+
+# ESPHome PR Workflow
+
+When creating a pull request for esphome, follow these steps:
+
+## 1. Create Branch from Upstream
+
+Always base your branch on **upstream** (not origin/fork) to ensure you have the latest code:
+
+```bash
+git fetch upstream
+git checkout -b <branch-name> upstream/dev
+```
+
+## 2. Read the PR Template
+
+Before creating a PR, read `.github/PULL_REQUEST_TEMPLATE.md` to understand required fields.
+
+## 3. Create the PR
+
+Use `gh pr create` with the **full template** filled in. Never skip or abbreviate sections.
+
+Required fields:
+- **What does this implement/fix?**: Brief description of changes
+- **Types of changes**: Check ONE appropriate box (Bugfix, New feature, Breaking change, etc.)
+- **Related issue**: Use `fixes <link>` syntax if applicable
+- **Pull request in esphome-docs**: Link if docs are needed
+- **Test Environment**: Check platforms you tested on
+- **Example config.yaml**: Include working example YAML
+- **Checklist**: Verify code is tested and tests added
+
+## 4. Example PR Body
+
+```markdown
+# What does this implement/fix?
+
+<describe your changes here>
+
+## Types of changes
+
+- [ ] Bugfix (non-breaking change which fixes an issue)
+- [x] New feature (non-breaking change which adds functionality)
+- [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
+- [ ] Developer breaking change (an API change that could break external components)
+- [ ] Code quality improvements to existing code or addition of tests
+- [ ] Other
+
+**Related issue or feature (if applicable):**
+
+- fixes https://github.com/esphome/esphome/issues/XXX
+
+**Pull request in [esphome-docs](https://github.com/esphome/esphome-docs) with documentation (if applicable):**
+
+- esphome/esphome-docs#XXX
+
+## Test Environment
+
+- [x] ESP32
+- [x] ESP32 IDF
+- [ ] ESP8266
+- [ ] RP2040
+- [ ] BK72xx
+- [ ] RTL87xx
+- [ ] LN882x
+- [ ] nRF52840
+
+## Example entry for `config.yaml`:
+
+```yaml
+# Example config.yaml
+component_name:
+  id: my_component
+  option: value
+```
+
+## Checklist:
+  - [x] The code change is tested and works locally.
+  - [x] Tests have been added to verify that the new code works (under `tests/` folder).
+
+If user exposed functionality or configuration variables are added/changed:
+  - [ ] Documentation added/updated in [esphome-docs](https://github.com/esphome/esphome-docs).
+```
+
+## 5. Push and Create PR
+
+```bash
+git push -u origin <branch-name>
+gh pr create --repo esphome/esphome --base dev --title "[component] Brief description"
+```
+
+Title should be prefixed with the component name in brackets, e.g. `[safe_mode] Add feature`.

.github/actions/restore-python/action.yml

@@ -22,7 +22,7 @@ runs:
         python-version: ${{ inputs.python-version }}
     - name: Restore Python virtual environment
       id: cache-venv
-      uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+      uses: actions/cache/restore@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
       with:
         path: venv
         # yamllint disable-line rule:line-length

.github/workflows/ci.yml

@@ -47,7 +47,7 @@ jobs:
           python-version: ${{ env.DEFAULT_PYTHON }}
       - name: Restore Python virtual environment
         id: cache-venv
-        uses: actions/cache@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: venv
           # yamllint disable-line rule:line-length
@@ -157,7 +157,7 @@ jobs:
           token: ${{ secrets.CODECOV_TOKEN }}
       - name: Save Python virtual environment cache
         if: github.ref == 'refs/heads/dev'
-        uses: actions/cache/save@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache/save@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: venv
           key: ${{ runner.os }}-${{ steps.restore-python.outputs.python-version }}-venv-${{ needs.common.outputs.cache-key }}
@@ -193,7 +193,7 @@ jobs:
           python-version: ${{ env.DEFAULT_PYTHON }}
           cache-key: ${{ needs.common.outputs.cache-key }}
       - name: Restore components graph cache
-        uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache/restore@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: .temp/components_graph.json
           key: components-graph-${{ hashFiles('esphome/components/**/*.py') }}
@@ -223,7 +223,7 @@ jobs:
           echo "component-test-batches=$(echo "$output" | jq -c '.component_test_batches')" >> $GITHUB_OUTPUT
       - name: Save components graph cache
         if: github.ref == 'refs/heads/dev'
-        uses: actions/cache/save@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache/save@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: .temp/components_graph.json
           key: components-graph-${{ hashFiles('esphome/components/**/*.py') }}
@@ -245,7 +245,7 @@ jobs:
           python-version: "3.13"
       - name: Restore Python virtual environment
         id: cache-venv
-        uses: actions/cache@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: venv
           key: ${{ runner.os }}-${{ steps.python.outputs.python-version }}-venv-${{ needs.common.outputs.cache-key }}
@@ -334,14 +334,14 @@ jobs:
 
       - name: Cache platformio
         if: github.ref == 'refs/heads/dev'
-        uses: actions/cache@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: ~/.platformio
           key: platformio-${{ matrix.pio_cache_key }}-${{ hashFiles('platformio.ini') }}
 
       - name: Cache platformio
         if: github.ref != 'refs/heads/dev'
-        uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache/restore@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: ~/.platformio
           key: platformio-${{ matrix.pio_cache_key }}-${{ hashFiles('platformio.ini') }}
@@ -413,14 +413,14 @@ jobs:
 
       - name: Cache platformio
         if: github.ref == 'refs/heads/dev'
-        uses: actions/cache@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: ~/.platformio
           key: platformio-tidyesp32-${{ hashFiles('platformio.ini') }}
 
       - name: Cache platformio
         if: github.ref != 'refs/heads/dev'
-        uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache/restore@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: ~/.platformio
           key: platformio-tidyesp32-${{ hashFiles('platformio.ini') }}
@@ -502,14 +502,14 @@ jobs:
 
       - name: Cache platformio
         if: github.ref == 'refs/heads/dev'
-        uses: actions/cache@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: ~/.platformio
           key: platformio-tidyesp32-${{ hashFiles('platformio.ini') }}
 
       - name: Cache platformio
         if: github.ref != 'refs/heads/dev'
-        uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache/restore@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: ~/.platformio
           key: platformio-tidyesp32-${{ hashFiles('platformio.ini') }}
@@ -735,7 +735,7 @@ jobs:
       - name: Restore cached memory analysis
         id: cache-memory-analysis
         if: steps.check-script.outputs.skip != 'true'
-        uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache/restore@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: memory-analysis-target.json
           key: ${{ steps.cache-key.outputs.cache-key }}
@@ -759,7 +759,7 @@ jobs:
 
       - name: Cache platformio
         if: steps.check-script.outputs.skip != 'true' && steps.cache-memory-analysis.outputs.cache-hit != 'true'
-        uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache/restore@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: ~/.platformio
           key: platformio-memory-${{ fromJSON(needs.determine-jobs.outputs.memory_impact).platform }}-${{ hashFiles('platformio.ini') }}
@@ -800,7 +800,7 @@ jobs:
 
       - name: Save memory analysis to cache
         if: steps.check-script.outputs.skip != 'true' && steps.cache-memory-analysis.outputs.cache-hit != 'true' && steps.build.outcome == 'success'
-        uses: actions/cache/save@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache/save@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: memory-analysis-target.json
           key: ${{ steps.cache-key.outputs.cache-key }}
@@ -847,7 +847,7 @@ jobs:
           python-version: ${{ env.DEFAULT_PYTHON }}
           cache-key: ${{ needs.common.outputs.cache-key }}
       - name: Cache platformio
-        uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
+        uses: actions/cache/restore@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
         with:
           path: ~/.platformio
           key: platformio-memory-${{ fromJSON(needs.determine-jobs.outputs.memory_impact).platform }}-${{ hashFiles('platformio.ini') }}

.pre-commit-config.yaml

@@ -11,7 +11,7 @@ ci:
 repos:
   - repo: https://github.com/astral-sh/ruff-pre-commit
     # Ruff version.
-    rev: v0.14.11
+    rev: v0.14.13
     hooks:
       # Run the linter.
       - id: ruff

Doxyfile

@@ -48,7 +48,7 @@ PROJECT_NAME           = ESPHome
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 2026.1.0
+PROJECT_NUMBER         = 2026.2.0-dev
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a

esphome/__main__.py

@@ -43,6 +43,7 @@ from esphome.const import (
     CONF_SUBSTITUTIONS,
     CONF_TOPIC,
     ENV_NOGITIGNORE,
+    KEY_NATIVE_IDF,
     PLATFORM_ESP32,
     PLATFORM_ESP8266,
     PLATFORM_RP2040,
@@ -116,6 +117,7 @@ class ArgsProtocol(Protocol):
     configuration: str
     name: str
     upload_speed: str | None
+    native_idf: bool
 
 
 def choose_prompt(options, purpose: str = None):
@@ -223,8 +225,13 @@ def choose_upload_log_host(
             else:
                 resolved.append(device)
         if not resolved:
+            if CORE.dashboard:
+                hint = "If you know the IP, set 'use_address' in your network config."
+            else:
+                hint = "If you know the IP, try --device <IP>"
             raise EsphomeError(
-                f"All specified devices {defaults} could not be resolved. Is the device connected to the network?"
+                f"All specified devices {defaults} could not be resolved. "
+                f"Is the device connected to the network? {hint}"
             )
         return resolved
 
@@ -495,12 +502,15 @@ def wrap_to_code(name, comp):
     return wrapped
 
 
-def write_cpp(config: ConfigType) -> int:
+def write_cpp(config: ConfigType, native_idf: bool = False) -> int:
     if not get_bool_env(ENV_NOGITIGNORE):
         writer.write_gitignore()
 
+    # Store native_idf flag so esp32 component can check it
+    CORE.data[KEY_NATIVE_IDF] = native_idf
+
     generate_cpp_contents(config)
-    return write_cpp_file()
+    return write_cpp_file(native_idf=native_idf)
 
 
 def generate_cpp_contents(config: ConfigType) -> None:
@@ -514,32 +524,54 @@ def generate_cpp_contents(config: ConfigType) -> None:
     CORE.flush_tasks()
 
 
-def write_cpp_file() -> int:
+def write_cpp_file(native_idf: bool = False) -> int:
     code_s = indent(CORE.cpp_main_section)
     writer.write_cpp(code_s)
 
-    from esphome.build_gen import platformio
+    if native_idf and CORE.is_esp32 and CORE.target_framework == "esp-idf":
+        from esphome.build_gen import espidf
 
-    platformio.write_project()
+        espidf.write_project()
+    else:
+        from esphome.build_gen import platformio
+
+        platformio.write_project()
 
     return 0
 
 
 def compile_program(args: ArgsProtocol, config: ConfigType) -> int:
-    from esphome import platformio_api
+    native_idf = getattr(args, "native_idf", False)
 
     # NOTE: "Build path:" format is parsed by script/ci_memory_impact_extract.py
     # If you change this format, update the regex in that script as well
     _LOGGER.info("Compiling app... Build path: %s", CORE.build_path)
-    rc = platformio_api.run_compile(config, CORE.verbose)
-    if rc != 0:
-        return rc
+
+    if native_idf and CORE.is_esp32 and CORE.target_framework == "esp-idf":
+        from esphome import espidf_api
+
+        rc = espidf_api.run_compile(config, CORE.verbose)
+        if rc != 0:
+            return rc
+
+        # Create factory.bin and ota.bin
+        espidf_api.create_factory_bin()
+        espidf_api.create_ota_bin()
+    else:
+        from esphome import platformio_api
+
+        rc = platformio_api.run_compile(config, CORE.verbose)
+        if rc != 0:
+            return rc
+
+        idedata = platformio_api.get_idedata(config)
+        if idedata is None:
+            return 1
 
     # Check if firmware was rebuilt and emit build_info + create manifest
     _check_and_emit_build_info()
 
-    idedata = platformio_api.get_idedata(config)
-    return 0 if idedata is not None else 1
+    return 0
 
 
 def _check_and_emit_build_info() -> None:
@@ -796,7 +828,8 @@ def command_vscode(args: ArgsProtocol) -> int | None:
 
 
 def command_compile(args: ArgsProtocol, config: ConfigType) -> int | None:
-    exit_code = write_cpp(config)
+    native_idf = getattr(args, "native_idf", False)
+    exit_code = write_cpp(config, native_idf=native_idf)
     if exit_code != 0:
         return exit_code
     if args.only_generate:
@@ -851,7 +884,8 @@ def command_logs(args: ArgsProtocol, config: ConfigType) -> int | None:
 
 
 def command_run(args: ArgsProtocol, config: ConfigType) -> int | None:
-    exit_code = write_cpp(config)
+    native_idf = getattr(args, "native_idf", False)
+    exit_code = write_cpp(config, native_idf=native_idf)
     if exit_code != 0:
         return exit_code
     exit_code = compile_program(args, config)
@@ -1305,6 +1339,11 @@ def parse_args(argv):
         help="Only generate source code, do not compile.",
         action="store_true",
     )
+    parser_compile.add_argument(
+        "--native-idf",
+        help="Build with native ESP-IDF instead of PlatformIO (ESP32 esp-idf framework only).",
+        action="store_true",
+    )
 
     parser_upload = subparsers.add_parser(
         "upload",
@@ -1386,6 +1425,11 @@ def parse_args(argv):
         help="Reset the device before starting serial logs.",
         default=os.getenv("ESPHOME_SERIAL_LOGGING_RESET"),
     )
+    parser_run.add_argument(
+        "--native-idf",
+        help="Build with native ESP-IDF instead of PlatformIO (ESP32 esp-idf framework only).",
+        action="store_true",
+    )
 
     parser_clean = subparsers.add_parser(
         "clean-mqtt",

esphome/analyze_memory/__init__.py

@@ -22,7 +22,7 @@ from .helpers import (
     map_section_name,
     parse_symbol_line,
 )
-from .toolchain import find_tool, run_tool
+from .toolchain import find_tool, resolve_tool_path, run_tool
 
 if TYPE_CHECKING:
     from esphome.platformio_api import IDEData
@@ -132,6 +132,12 @@ class MemoryAnalyzer:
             readelf_path = readelf_path or idedata.readelf_path
             _LOGGER.debug("Using toolchain paths from PlatformIO idedata")
 
+        # Validate paths exist, fall back to find_tool if they don't
+        # This handles cases like Zephyr where cc_path doesn't include full path
+        # and the toolchain prefix may differ (e.g., arm-zephyr-eabi- vs arm-none-eabi-)
+        objdump_path = resolve_tool_path("objdump", objdump_path, objdump_path)
+        readelf_path = resolve_tool_path("readelf", readelf_path, objdump_path)
+
         self.objdump_path = objdump_path or "objdump"
         self.readelf_path = readelf_path or "readelf"
         self.external_components = external_components or set()

esphome/analyze_memory/const.py

@@ -9,11 +9,61 @@ ESPHOME_COMPONENT_PATTERN = re.compile(r"esphome::([a-zA-Z0-9_]+)::")
 # Maps standard section names to their various platform-specific variants
 # Note: Order matters! More specific patterns (.bss) must come before general ones (.dram)
 # because ESP-IDF uses names like ".dram0.bss" which would match ".dram" otherwise
+#
+# Platform-specific sections:
+# - ESP8266/ESP32: .iram*, .dram*
+# - LibreTiny RTL87xx: .xip.code_* (flash), .ram.code_* (RAM)
+# - LibreTiny BK7231: .itcm.code (fast RAM), .vectors (interrupt vectors)
+# - LibreTiny LN882X: .flash_text, .flash_copy* (flash code)
+# - Zephyr/nRF52: text, rodata, datas, bss (no leading dots)
 SECTION_MAPPING = {
-    ".text": frozenset([".text", ".iram"]),
-    ".rodata": frozenset([".rodata"]),
-    ".bss": frozenset([".bss"]),  # Must be before .data to catch ".dram0.bss"
-    ".data": frozenset([".data", ".dram"]),
+    ".text": frozenset(
+        [
+            ".text",
+            ".iram",
+            # LibreTiny RTL87xx XIP (eXecute In Place) flash code
+            ".xip.code",
+            # LibreTiny RTL87xx RAM code
+            ".ram.code_text",
+            # LibreTiny BK7231 fast RAM code and vectors
+            ".itcm.code",
+            ".vectors",
+            # LibreTiny LN882X flash code
+            ".flash_text",
+            ".flash_copy",
+            # Zephyr/nRF52 sections (no leading dots)
+            "text",
+            "rom_start",
+        ]
+    ),
+    ".rodata": frozenset(
+        [
+            ".rodata",
+            # LibreTiny RTL87xx read-only data in RAM
+            ".ram.code_rodata",
+            # Zephyr/nRF52 sections (no leading dots)
+            "rodata",
+        ]
+    ),
+    # .bss patterns - must be before .data to catch ".dram0.bss"
+    ".bss": frozenset(
+        [
+            ".bss",
+            # LibreTiny LN882X BSS
+            ".bss_ram",
+            # Zephyr/nRF52 sections (no leading dots)
+            "bss",
+            "noinit",
+        ]
+    ),
+    ".data": frozenset(
+        [
+            ".data",
+            ".dram",
+            # Zephyr/nRF52 sections (no leading dots)
+            "datas",
+        ]
+    ),
 }
 
 # Section to ComponentMemory attribute mapping

esphome/analyze_memory/helpers.py

@@ -94,13 +94,13 @@ def parse_symbol_line(line: str) -> tuple[str, str, int, str] | None:
         return None
 
     # Find section, size, and name
+    # Try each part as a potential section name
     for i, part in enumerate(parts):
-        if not part.startswith("."):
-            continue
-
+        # Skip parts that are clearly flags, addresses, or other metadata
+        # Sections start with '.' (standard ELF) or are known section names (Zephyr)
         section = map_section_name(part)
         if not section:
-            break
+            continue
 
         # Need at least size field after section
         if i + 1 >= len(parts):

esphome/analyze_memory/toolchain.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import logging
+import os
 from pathlib import Path
 import subprocess
 from typing import TYPE_CHECKING
@@ -17,10 +18,82 @@ TOOLCHAIN_PREFIXES = [
     "xtensa-lx106-elf-",  # ESP8266
     "xtensa-esp32-elf-",  # ESP32
     "xtensa-esp-elf-",  # ESP32 (newer IDF)
+    "arm-zephyr-eabi-",  # nRF52/Zephyr SDK
+    "arm-none-eabi-",  # Generic ARM (RP2040, etc.)
     "",  # System default (no prefix)
 ]
 
 
+def _find_in_platformio_packages(tool_name: str) -> str | None:
+    """Search for a tool in PlatformIO package directories.
+
+    This handles cases like Zephyr SDK where tools are installed in nested
+    directories that aren't in PATH.
+
+    Args:
+        tool_name: Name of the tool (e.g., "readelf", "objdump")
+
+    Returns:
+        Full path to the tool or None if not found
+    """
+    # Get PlatformIO packages directory
+    platformio_home = Path(os.path.expanduser("~/.platformio/packages"))
+    if not platformio_home.exists():
+        return None
+
+    # Search patterns for toolchains that might contain the tool
+    # Order matters - more specific patterns first
+    search_patterns = [
+        # Zephyr SDK deeply nested structure (4 levels)
+        # e.g., toolchain-gccarmnoneeabi/zephyr-sdk-0.17.4/arm-zephyr-eabi/bin/arm-zephyr-eabi-objdump
+        f"toolchain-*/*/*/bin/*-{tool_name}",
+        # Zephyr SDK nested structure (3 levels)
+        f"toolchain-*/*/bin/*-{tool_name}",
+        f"toolchain-*/bin/*-{tool_name}",
+        # Standard PlatformIO toolchain structure
+        f"toolchain-*/bin/*{tool_name}",
+    ]
+
+    for pattern in search_patterns:
+        matches = list(platformio_home.glob(pattern))
+        if matches:
+            # Sort to get consistent results, prefer arm-zephyr-eabi over arm-none-eabi
+            matches.sort(key=lambda p: ("zephyr" not in str(p), str(p)))
+            tool_path = str(matches[0])
+            _LOGGER.debug("Found %s in PlatformIO packages: %s", tool_name, tool_path)
+            return tool_path
+
+    return None
+
+
+def resolve_tool_path(
+    tool_name: str,
+    derived_path: str | None,
+    objdump_path: str | None = None,
+) -> str | None:
+    """Resolve a tool path, falling back to find_tool if derived path doesn't exist.
+
+    Args:
+        tool_name: Name of the tool (e.g., "objdump", "readelf")
+        derived_path: Path derived from idedata (may not exist for some platforms)
+        objdump_path: Path to objdump binary to derive other tool paths from
+
+    Returns:
+        Resolved path to the tool, or the original derived_path if it exists
+    """
+    if derived_path and not Path(derived_path).exists():
+        found = find_tool(tool_name, objdump_path)
+        if found:
+            _LOGGER.debug(
+                "Derived %s path %s not found, using %s",
+                tool_name,
+                derived_path,
+                found,
+            )
+            return found
+    return derived_path
+
+
 def find_tool(
     tool_name: str,
     objdump_path: str | None = None,
@@ -28,7 +101,8 @@ def find_tool(
     """Find a toolchain tool by name.
 
     First tries to derive the tool path from objdump_path (if provided),
-    then falls back to searching for platform-specific tools.
+    then searches PlatformIO package directories (for cross-compile toolchains),
+    and finally falls back to searching for platform-specific tools in PATH.
 
     Args:
         tool_name: Name of the tool (e.g., "objdump", "nm", "c++filt")
@@ -47,7 +121,13 @@ def find_tool(
             _LOGGER.debug("Found %s at: %s", tool_name, potential_path)
             return potential_path
 
-    # Try platform-specific tools
+    # Search in PlatformIO packages directory first (handles Zephyr SDK, etc.)
+    # This must come before PATH search because system tools (e.g., /usr/bin/objdump)
+    # are for the host architecture, not the target (ARM, Xtensa, etc.)
+    if found := _find_in_platformio_packages(tool_name):
+        return found
+
+    # Try platform-specific tools in PATH (fallback for when tools are installed globally)
     for prefix in TOOLCHAIN_PREFIXES:
         cmd = f"{prefix}{tool_name}"
         try:

esphome/build_gen/espidf.py

@@ -0,0 +1,139 @@
+"""ESP-IDF direct build generator for ESPHome."""
+
+import json
+from pathlib import Path
+
+from esphome.components.esp32 import get_esp32_variant
+from esphome.core import CORE
+from esphome.helpers import mkdir_p, write_file_if_changed
+
+
+def get_available_components() -> list[str] | None:
+    """Get list of available ESP-IDF components from project_description.json.
+
+    Returns only internal ESP-IDF components, excluding external/managed
+    components (from idf_component.yml).
+    """
+    project_desc = Path(CORE.build_path) / "build" / "project_description.json"
+    if not project_desc.exists():
+        return None
+
+    try:
+        with open(project_desc, encoding="utf-8") as f:
+            data = json.load(f)
+
+        component_info = data.get("build_component_info", {})
+
+        result = []
+        for name, info in component_info.items():
+            # Exclude our own src component
+            if name == "src":
+                continue
+
+            # Exclude managed/external components
+            comp_dir = info.get("dir", "")
+            if "managed_components" in comp_dir:
+                continue
+
+            result.append(name)
+
+        return result
+    except (json.JSONDecodeError, OSError):
+        return None
+
+
+def has_discovered_components() -> bool:
+    """Check if we have discovered components from a previous configure."""
+    return get_available_components() is not None
+
+
+def get_project_cmakelists() -> str:
+    """Generate the top-level CMakeLists.txt for ESP-IDF project."""
+    # Get IDF target from ESP32 variant (e.g., ESP32S3 -> esp32s3)
+    variant = get_esp32_variant()
+    idf_target = variant.lower().replace("-", "")
+
+    return f"""\
+# Auto-generated by ESPHome
+cmake_minimum_required(VERSION 3.16)
+
+set(IDF_TARGET {idf_target})
+set(EXTRA_COMPONENT_DIRS ${{CMAKE_SOURCE_DIR}}/src)
+
+include($ENV{{IDF_PATH}}/tools/cmake/project.cmake)
+project({CORE.name})
+"""
+
+
+def get_component_cmakelists(minimal: bool = False) -> str:
+    """Generate the main component CMakeLists.txt."""
+    idf_requires = [] if minimal else (get_available_components() or [])
+    requires_str = " ".join(idf_requires)
+
+    # Extract compile definitions from build flags (-DXXX -> XXX)
+    compile_defs = [flag[2:] for flag in CORE.build_flags if flag.startswith("-D")]
+    compile_defs_str = "\n    ".join(compile_defs) if compile_defs else ""
+
+    # Extract compile options (-W flags, excluding linker flags)
+    compile_opts = [
+        flag
+        for flag in CORE.build_flags
+        if flag.startswith("-W") and not flag.startswith("-Wl,")
+    ]
+    compile_opts_str = "\n    ".join(compile_opts) if compile_opts else ""
+
+    # Extract linker options (-Wl, flags)
+    link_opts = [flag for flag in CORE.build_flags if flag.startswith("-Wl,")]
+    link_opts_str = "\n    ".join(link_opts) if link_opts else ""
+
+    return f"""\
+# Auto-generated by ESPHome
+file(GLOB_RECURSE app_sources
+    "${{CMAKE_CURRENT_SOURCE_DIR}}/*.cpp"
+    "${{CMAKE_CURRENT_SOURCE_DIR}}/*.c"
+    "${{CMAKE_CURRENT_SOURCE_DIR}}/esphome/*.cpp"
+    "${{CMAKE_CURRENT_SOURCE_DIR}}/esphome/*.c"
+)
+
+idf_component_register(
+    SRCS ${{app_sources}}
+    INCLUDE_DIRS "." "esphome"
+    REQUIRES {requires_str}
+)
+
+# Apply C++ standard
+target_compile_features(${{COMPONENT_LIB}} PUBLIC cxx_std_20)
+
+# ESPHome compile definitions
+target_compile_definitions(${{COMPONENT_LIB}} PUBLIC
+    {compile_defs_str}
+)
+
+# ESPHome compile options
+target_compile_options(${{COMPONENT_LIB}} PUBLIC
+    {compile_opts_str}
+)
+
+# ESPHome linker options
+target_link_options(${{COMPONENT_LIB}} PUBLIC
+    {link_opts_str}
+)
+"""
+
+
+def write_project(minimal: bool = False) -> None:
+    """Write ESP-IDF project files."""
+    mkdir_p(CORE.build_path)
+    mkdir_p(CORE.relative_src_path())
+
+    # Write top-level CMakeLists.txt
+    write_file_if_changed(
+        CORE.relative_build_path("CMakeLists.txt"),
+        get_project_cmakelists(),
+    )
+
+    # Write component CMakeLists.txt in src/
+    write_file_if_changed(
+        CORE.relative_src_path("CMakeLists.txt"),
+        get_component_cmakelists(minimal=minimal),
+    )

esphome/codegen.py

@@ -69,6 +69,7 @@ from esphome.cpp_types import (  # noqa: F401
     JsonObjectConst,
     Parented,
     PollingComponent,
+    StringRef,
     arduino_json_ns,
     bool_,
     const_char_ptr,

esphome/components/am43/am43_base.cpp

@@ -1,21 +1,12 @@
 #include "am43_base.h"
+#include "esphome/core/helpers.h"
 #include <cstring>
-#include <cstdio>
 
 namespace esphome {
 namespace am43 {
 
 const uint8_t START_PACKET[5] = {0x00, 0xff, 0x00, 0x00, 0x9a};
 
-std::string pkt_to_hex(const uint8_t *data, uint16_t len) {
-  char buf[64];
-  memset(buf, 0, 64);
-  for (int i = 0; i < len; i++)
-    sprintf(&buf[i * 2], "%02x", data[i]);
-  std::string ret = buf;
-  return ret;
-}
-
 Am43Packet *Am43Encoder::get_battery_level_request() {
   uint8_t data = 0x1;
   return this->encode_(0xA2, &data, 1);
@@ -73,7 +64,9 @@ Am43Packet *Am43Encoder::encode_(uint8_t command, uint8_t *data, uint8_t length)
   memcpy(&this->packet_.data[7], data, length);
   this->packet_.length = length + 7;
   this->checksum_();
-  ESP_LOGV("am43", "ENC(%d): 0x%s", packet_.length, pkt_to_hex(packet_.data, packet_.length).c_str());
+  char hex_buf[format_hex_size(sizeof(this->packet_.data))];
+  ESP_LOGV("am43", "ENC(%d): 0x%s", this->packet_.length,
+           format_hex_to(hex_buf, this->packet_.data, this->packet_.length));
   return &this->packet_;
 }
 
@@ -88,7 +81,8 @@ void Am43Decoder::decode(const uint8_t *data, uint16_t length) {
   this->has_set_state_response_ = false;
   this->has_position_ = false;
   this->has_pin_response_ = false;
-  ESP_LOGV("am43", "DEC(%d): 0x%s", length, pkt_to_hex(data, length).c_str());
+  char hex_buf[format_hex_size(24)];  // Max expected packet size
+  ESP_LOGV("am43", "DEC(%d): 0x%s", length, format_hex_to(hex_buf, data, length));
 
   if (length < 2 || data[0] != 0x9a)
     return;

esphome/components/anova/anova_base.cpp

@@ -18,31 +18,31 @@ AnovaPacket *AnovaCodec::clean_packet_() {
 
 AnovaPacket *AnovaCodec::get_read_device_status_request() {
   this->current_query_ = READ_DEVICE_STATUS;
-  sprintf((char *) this->packet_.data, "%s", CMD_READ_DEVICE_STATUS);
+  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), "%s", CMD_READ_DEVICE_STATUS);
   return this->clean_packet_();
 }
 
 AnovaPacket *AnovaCodec::get_read_target_temp_request() {
   this->current_query_ = READ_TARGET_TEMPERATURE;
-  sprintf((char *) this->packet_.data, "%s", CMD_READ_TARGET_TEMP);
+  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), "%s", CMD_READ_TARGET_TEMP);
   return this->clean_packet_();
 }
 
 AnovaPacket *AnovaCodec::get_read_current_temp_request() {
   this->current_query_ = READ_CURRENT_TEMPERATURE;
-  sprintf((char *) this->packet_.data, "%s", CMD_READ_CURRENT_TEMP);
+  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), "%s", CMD_READ_CURRENT_TEMP);
   return this->clean_packet_();
 }
 
 AnovaPacket *AnovaCodec::get_read_unit_request() {
   this->current_query_ = READ_UNIT;
-  sprintf((char *) this->packet_.data, "%s", CMD_READ_UNIT);
+  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), "%s", CMD_READ_UNIT);
   return this->clean_packet_();
 }
 
 AnovaPacket *AnovaCodec::get_read_data_request() {
   this->current_query_ = READ_DATA;
-  sprintf((char *) this->packet_.data, "%s", CMD_READ_DATA);
+  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), "%s", CMD_READ_DATA);
   return this->clean_packet_();
 }
 
@@ -50,25 +50,25 @@ AnovaPacket *AnovaCodec::get_set_target_temp_request(float temperature) {
   this->current_query_ = SET_TARGET_TEMPERATURE;
   if (this->fahrenheit_)
     temperature = ctof(temperature);
-  sprintf((char *) this->packet_.data, CMD_SET_TARGET_TEMP, temperature);
+  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), CMD_SET_TARGET_TEMP, temperature);
   return this->clean_packet_();
 }
 
 AnovaPacket *AnovaCodec::get_set_unit_request(char unit) {
   this->current_query_ = SET_UNIT;
-  sprintf((char *) this->packet_.data, CMD_SET_TEMP_UNIT, unit);
+  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), CMD_SET_TEMP_UNIT, unit);
   return this->clean_packet_();
 }
 
 AnovaPacket *AnovaCodec::get_start_request() {
   this->current_query_ = START;
-  sprintf((char *) this->packet_.data, CMD_START);
+  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), "%s", CMD_START);
   return this->clean_packet_();
 }
 
 AnovaPacket *AnovaCodec::get_stop_request() {
   this->current_query_ = STOP;
-  sprintf((char *) this->packet_.data, CMD_STOP);
+  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), "%s", CMD_STOP);
   return this->clean_packet_();
 }
 

esphome/components/api/api_connection.cpp

@@ -1715,7 +1715,7 @@ void APIConnection::on_home_assistant_state_response(const HomeAssistantStateRes
     // HA state max length is 255 characters, but attributes can be much longer
     // Use stack buffer for common case (states), heap fallback for large attributes
     size_t state_len = msg.state.size();
-    SmallBufferWithHeapFallback<256> state_buf_alloc(state_len + 1);
+    SmallBufferWithHeapFallback<MAX_STATE_LEN + 1> state_buf_alloc(state_len + 1);
     char *state_buf = reinterpret_cast<char *>(state_buf_alloc.get());
     if (state_len > 0) {
       memcpy(state_buf, msg.state.c_str(), state_len);

esphome/components/api/api_frame_helper_noise.cpp

@@ -3,6 +3,7 @@
 #ifdef USE_API_NOISE
 #include "api_connection.h"  // For ClientInfo struct
 #include "esphome/core/application.h"
+#include "esphome/core/entity_base.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
@@ -256,28 +257,30 @@ APIError APINoiseFrameHelper::state_action_() {
   }
   if (state_ == State::SERVER_HELLO) {
     // send server hello
-    constexpr size_t mac_len = 13;  // 12 hex chars + null terminator
     const std::string &name = App.get_name();
-    char mac[mac_len];
+    char mac[MAC_ADDRESS_BUFFER_SIZE];
     get_mac_address_into_buffer(mac);
 
     // Calculate positions and sizes
     size_t name_len = name.size() + 1;  // including null terminator
     size_t name_offset = 1;
     size_t mac_offset = name_offset + name_len;
-    size_t total_size = 1 + name_len + mac_len;
+    size_t total_size = 1 + name_len + MAC_ADDRESS_BUFFER_SIZE;
 
-    auto msg = std::make_unique<uint8_t[]>(total_size);
+    // 1 (proto) + name (max ESPHOME_DEVICE_NAME_MAX_LEN) + 1 (name null)
+    // + mac (MAC_ADDRESS_BUFFER_SIZE - 1) + 1 (mac null)
+    constexpr size_t max_msg_size = 1 + ESPHOME_DEVICE_NAME_MAX_LEN + 1 + MAC_ADDRESS_BUFFER_SIZE;
+    uint8_t msg[max_msg_size];
 
     // chosen proto
     msg[0] = 0x01;
 
     // node name, terminated by null byte
-    std::memcpy(msg.get() + name_offset, name.c_str(), name_len);
+    std::memcpy(msg + name_offset, name.c_str(), name_len);
     // node mac, terminated by null byte
-    std::memcpy(msg.get() + mac_offset, mac, mac_len);
+    std::memcpy(msg + mac_offset, mac, MAC_ADDRESS_BUFFER_SIZE);
 
-    aerr = write_frame_(msg.get(), total_size);
+    aerr = write_frame_(msg, total_size);
     if (aerr != APIError::OK)
       return aerr;
 
@@ -353,35 +356,32 @@ APIError APINoiseFrameHelper::state_action_() {
   return APIError::OK;
 }
 void APINoiseFrameHelper::send_explicit_handshake_reject_(const LogString *reason) {
+  // Max reject message: "Bad handshake packet len" (24) + 1 (failure byte) = 25 bytes
+  uint8_t data[32];
+  data[0] = 0x01;  // failure
+
 #ifdef USE_STORE_LOG_STR_IN_FLASH
   // On ESP8266 with flash strings, we need to use PROGMEM-aware functions
   size_t reason_len = strlen_P(reinterpret_cast<PGM_P>(reason));
-  size_t data_size = reason_len + 1;
-  auto data = std::make_unique<uint8_t[]>(data_size);
-  data[0] = 0x01;  // failure
-
-  // Copy error message from PROGMEM
   if (reason_len > 0) {
-    memcpy_P(data.get() + 1, reinterpret_cast<PGM_P>(reason), reason_len);
+    memcpy_P(data + 1, reinterpret_cast<PGM_P>(reason), reason_len);
   }
 #else
   // Normal memory access
   const char *reason_str = LOG_STR_ARG(reason);
   size_t reason_len = strlen(reason_str);
-  size_t data_size = reason_len + 1;
-  auto data = std::make_unique<uint8_t[]>(data_size);
-  data[0] = 0x01;  // failure
-
-  // Copy error message in bulk
   if (reason_len > 0) {
-    std::memcpy(data.get() + 1, reason_str, reason_len);
+    // NOLINTNEXTLINE(bugprone-not-null-terminated-result) - binary protocol, not a C string
+    std::memcpy(data + 1, reason_str, reason_len);
   }
 #endif
 
+  size_t data_size = reason_len + 1;
+
   // temporarily remove failed state
   auto orig_state = state_;
   state_ = State::EXPLICIT_REJECT;
-  write_frame_(data.get(), data_size);
+  write_frame_(data, data_size);
   state_ = orig_state;
 }
 APIError APINoiseFrameHelper::read_packet(ReadPacketBuffer *buffer) {

esphome/components/atm90e32/atm90e32.cpp

@@ -158,12 +158,14 @@ void ATM90E32Component::setup() {
 
   if (this->enable_offset_calibration_) {
     // Initialize flash storage for offset calibrations
-    uint32_t o_hash = fnv1_hash(std::string("_offset_calibration_") + this->cs_summary_);
+    uint32_t o_hash = fnv1_hash("_offset_calibration_");
+    o_hash = fnv1_hash_extend(o_hash, this->cs_summary_);
     this->offset_pref_ = global_preferences->make_preference<OffsetCalibration[3]>(o_hash, true);
     this->restore_offset_calibrations_();
 
     // Initialize flash storage for power offset calibrations
-    uint32_t po_hash = fnv1_hash(std::string("_power_offset_calibration_") + this->cs_summary_);
+    uint32_t po_hash = fnv1_hash("_power_offset_calibration_");
+    po_hash = fnv1_hash_extend(po_hash, this->cs_summary_);
     this->power_offset_pref_ = global_preferences->make_preference<PowerOffsetCalibration[3]>(po_hash, true);
     this->restore_power_offset_calibrations_();
   } else {
@@ -183,7 +185,8 @@ void ATM90E32Component::setup() {
 
   if (this->enable_gain_calibration_) {
     // Initialize flash storage for gain calibration
-    uint32_t g_hash = fnv1_hash(std::string("_gain_calibration_") + this->cs_summary_);
+    uint32_t g_hash = fnv1_hash("_gain_calibration_");
+    g_hash = fnv1_hash_extend(g_hash, this->cs_summary_);
     this->gain_calibration_pref_ = global_preferences->make_preference<GainCalibration[3]>(g_hash, true);
     this->restore_gain_calibrations_();
 

esphome/components/audio/audio_reader.cpp

@@ -185,18 +185,16 @@ esp_err_t AudioReader::start(const std::string &uri, AudioFileType &file_type) {
       return err;
     }
 
-    std::string url_string = str_lower_case(url);
-
-    if (str_endswith(url_string, ".wav")) {
+    if (str_endswith_ignore_case(url, ".wav")) {
       file_type = AudioFileType::WAV;
     }
 #ifdef USE_AUDIO_MP3_SUPPORT
-    else if (str_endswith(url_string, ".mp3")) {
+    else if (str_endswith_ignore_case(url, ".mp3")) {
       file_type = AudioFileType::MP3;
     }
 #endif
 #ifdef USE_AUDIO_FLAC_SUPPORT
-    else if (str_endswith(url_string, ".flac")) {
+    else if (str_endswith_ignore_case(url, ".flac")) {
       file_type = AudioFileType::FLAC;
     }
 #endif

esphome/components/bluetooth_proxy/bluetooth_connection.cpp

@@ -135,8 +135,8 @@ void BluetoothConnection::loop() {
   // - For V3_WITH_CACHE: Services are never sent, disable after INIT state
   // - For V3_WITHOUT_CACHE: Disable only after service discovery is complete
   //   (send_service_ == DONE_SENDING_SERVICES, which is only set after services are sent)
-  if (this->state_ != espbt::ClientState::INIT && (this->connection_type_ == espbt::ConnectionType::V3_WITH_CACHE ||
-                                                   this->send_service_ == DONE_SENDING_SERVICES)) {
+  if (this->state() != espbt::ClientState::INIT && (this->connection_type_ == espbt::ConnectionType::V3_WITH_CACHE ||
+                                                    this->send_service_ == DONE_SENDING_SERVICES)) {
     this->disable_loop();
   }
 }

esphome/components/captive_portal/captive_portal.cpp

@@ -96,10 +96,16 @@ void CaptivePortal::start() {
 }
 
 void CaptivePortal::handleRequest(AsyncWebServerRequest *req) {
-  if (req->url() == ESPHOME_F("/config.json")) {
+#ifdef USE_ESP32
+  char url_buf[AsyncWebServerRequest::URL_BUF_SIZE];
+  StringRef url = req->url_to(url_buf);
+#else
+  const auto &url = req->url();
+#endif
+  if (url == ESPHOME_F("/config.json")) {
     this->handle_config(req);
     return;
-  } else if (req->url() == ESPHOME_F("/wifisave")) {
+  } else if (url == ESPHOME_F("/wifisave")) {
     this->handle_wifisave(req);
     return;
   }

esphome/components/cc1101/cc1101.cpp

@@ -152,6 +152,13 @@ void CC1101Component::setup() {
   }
 }
 
+void CC1101Component::call_listeners_(const std::vector<uint8_t> &packet, float freq_offset, float rssi, uint8_t lqi) {
+  for (auto &listener : this->listeners_) {
+    listener->on_packet(packet, freq_offset, rssi, lqi);
+  }
+  this->packet_trigger_->trigger(packet, freq_offset, rssi, lqi);
+}
+
 void CC1101Component::loop() {
   if (this->state_.PKT_FORMAT != static_cast<uint8_t>(PacketFormat::PACKET_FORMAT_FIFO) || this->gdo0_pin_ == nullptr ||
       !this->gdo0_pin_->digital_read()) {
@@ -198,7 +205,7 @@ void CC1101Component::loop() {
   bool crc_ok = (this->state_.LQI & STATUS_CRC_OK_MASK) != 0;
   uint8_t lqi = this->state_.LQI & STATUS_LQI_MASK;
   if (this->state_.CRC_EN == 0 || crc_ok) {
-    this->packet_trigger_->trigger(this->packet_, freq_offset, rssi, lqi);
+    this->call_listeners_(this->packet_, freq_offset, rssi, lqi);
   }
 
   // Return to rx

esphome/components/cc1101/cc1101.h

@@ -11,6 +11,11 @@ namespace esphome::cc1101 {
 
 enum class CC1101Error { NONE = 0, TIMEOUT, PARAMS, CRC_ERROR, FIFO_OVERFLOW, PLL_LOCK };
 
+class CC1101Listener {
+ public:
+  virtual void on_packet(const std::vector<uint8_t> &packet, float freq_offset, float rssi, uint8_t lqi) = 0;
+};
+
 class CC1101Component : public Component,
                         public spi::SPIDevice<spi::BIT_ORDER_MSB_FIRST, spi::CLOCK_POLARITY_LOW,
                                               spi::CLOCK_PHASE_LEADING, spi::DATA_RATE_1MHZ> {
@@ -73,6 +78,7 @@ class CC1101Component : public Component,
 
   // Packet mode operations
   CC1101Error transmit_packet(const std::vector<uint8_t> &packet);
+  void register_listener(CC1101Listener *listener) { this->listeners_.push_back(listener); }
   Trigger<std::vector<uint8_t>, float, float, uint8_t> *get_packet_trigger() const { return this->packet_trigger_; }
 
  protected:
@@ -89,9 +95,11 @@ class CC1101Component : public Component,
   InternalGPIOPin *gdo0_pin_{nullptr};
 
   // Packet handling
+  void call_listeners_(const std::vector<uint8_t> &packet, float freq_offset, float rssi, uint8_t lqi);
   Trigger<std::vector<uint8_t>, float, float, uint8_t> *packet_trigger_{
       new Trigger<std::vector<uint8_t>, float, float, uint8_t>()};
   std::vector<uint8_t> packet_;
+  std::vector<CC1101Listener *> listeners_;
 
   // Low-level Helpers
   uint8_t strobe_(Command cmd);

esphome/components/ccs811/ccs811.cpp

@@ -81,8 +81,8 @@ void CCS811Component::setup() {
            bootloader_version, application_version);
   if (this->version_ != nullptr) {
     char version[20];  // "15.15.15 (0xffff)" is 17 chars, plus NUL, plus wiggle room
-    sprintf(version, "%d.%d.%d (0x%02x)", (application_version >> 12 & 15), (application_version >> 8 & 15),
-            (application_version >> 4 & 15), application_version);
+    buf_append_printf(version, sizeof(version), 0, "%d.%d.%d (0x%02x)", (application_version >> 12 & 15),
+                      (application_version >> 8 & 15), (application_version >> 4 & 15), application_version);
     ESP_LOGD(TAG, "publishing version state: %s", version);
     this->version_->publish_state(version);
   }

esphome/components/ch422g/ch422g.cpp

@@ -133,7 +133,7 @@ bool CH422GGPIOPin::digital_read() { return this->parent_->digital_read(this->pi
 
 void CH422GGPIOPin::digital_write(bool value) { this->parent_->digital_write(this->pin_, value ^ this->inverted_); }
 size_t CH422GGPIOPin::dump_summary(char *buffer, size_t len) const {
-  return snprintf(buffer, len, "EXIO%u via CH422G", this->pin_);
+  return buf_append_printf(buffer, len, 0, "EXIO%u via CH422G", this->pin_);
 }
 void CH422GGPIOPin::set_flags(gpio::Flags flags) {
   flags_ = flags;

esphome/components/cs5460a/cs5460a.h

@@ -76,7 +76,6 @@ class CS5460AComponent : public Component,
   void restart() { restart_(); }
 
   void setup() override;
-  void loop() override {}
   void dump_config() override;
 
  protected:

esphome/components/cse7766/cse7766.cpp

@@ -207,20 +207,24 @@ void CSE7766Component::parse_data_() {
 
 #if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERY_VERBOSE
   {
-    std::string buf = "Parsed:";
+    // Buffer: 7 + 15 + 33 + 15 + 25 = 95 chars max + null, rounded to 128 for safety margin.
+    // Float sizes with %.4f can be up to 11 chars for large values (e.g., 999999.9999).
+    char buf[128];
+    size_t pos = buf_append_printf(buf, sizeof(buf), 0, "Parsed:");
     if (have_voltage) {
-      buf += str_sprintf(" V=%fV", voltage);
+      pos = buf_append_printf(buf, sizeof(buf), pos, " V=%.4fV", voltage);
     }
     if (have_current) {
-      buf += str_sprintf(" I=%fmA (~%fmA)", current * 1000.0f, calculated_current * 1000.0f);
+      pos = buf_append_printf(buf, sizeof(buf), pos, " I=%.4fmA (~%.4fmA)", current * 1000.0f,
+                              calculated_current * 1000.0f);
     }
     if (have_power) {
-      buf += str_sprintf(" P=%fW", power);
+      pos = buf_append_printf(buf, sizeof(buf), pos, " P=%.4fW", power);
     }
     if (energy != 0.0f) {
-      buf += str_sprintf(" E=%fkWh (%u)", energy, cf_pulses);
+      buf_append_printf(buf, sizeof(buf), pos, " E=%.4fkWh (%u)", energy, cf_pulses);
     }
-    ESP_LOGVV(TAG, "%s", buf.c_str());
+    ESP_LOGVV(TAG, "%s", buf);
   }
 #endif
 }

esphome/components/daikin_arc/daikin_arc.cpp

@@ -258,8 +258,9 @@ bool DaikinArcClimate::parse_state_frame_(const uint8_t frame[]) {
   }
 
   char buf[DAIKIN_STATE_FRAME_SIZE * 3 + 1] = {0};
+  size_t pos = 0;
   for (size_t i = 0; i < DAIKIN_STATE_FRAME_SIZE; i++) {
-    sprintf(buf, "%s%02x ", buf, frame[i]);
+    pos = buf_append_printf(buf, sizeof(buf), pos, "%02x ", frame[i]);
   }
   ESP_LOGD(TAG, "FRAME %s", buf);
 
@@ -349,8 +350,9 @@ bool DaikinArcClimate::on_receive(remote_base::RemoteReceiveData data) {
   if (data.expect_item(DAIKIN_HEADER_MARK, DAIKIN_HEADER_SPACE)) {
     valid_daikin_frame = true;
     size_t bytes_count = data.size() / 2 / 8;
-    std::unique_ptr<char[]> buf(new char[bytes_count * 3 + 1]);
-    buf[0] = '\0';
+    size_t buf_size = bytes_count * 3 + 1;
+    std::unique_ptr<char[]> buf(new char[buf_size]());  // value-initialize (zero-fill)
+    size_t buf_pos = 0;
     for (size_t i = 0; i < bytes_count; i++) {
       uint8_t byte = 0;
       for (int8_t bit = 0; bit < 8; bit++) {
@@ -361,19 +363,19 @@ bool DaikinArcClimate::on_receive(remote_base::RemoteReceiveData data) {
           break;
         }
       }
-      sprintf(buf.get(), "%s%02x ", buf.get(), byte);
+      buf_pos = buf_append_printf(buf.get(), buf_size, buf_pos, "%02x ", byte);
     }
     ESP_LOGD(TAG, "WHOLE FRAME %s  size: %d", buf.get(), data.size());
   }
   if (!valid_daikin_frame) {
-    char sbuf[16 * 10 + 1];
-    sbuf[0] = '\0';
+    char sbuf[16 * 10 + 1] = {0};
+    size_t sbuf_pos = 0;
     for (size_t j = 0; j < static_cast<size_t>(data.size()); j++) {
       if ((j - 2) % 16 == 0) {
         if (j > 0) {
           ESP_LOGD(TAG, "DATA %04x: %s", (j - 16 > 0xffff ? 0 : j - 16), sbuf);
         }
-        sbuf[0] = '\0';
+        sbuf_pos = 0;
       }
       char type_ch = ' ';
       // debug_tolerance = 25%
@@ -401,9 +403,10 @@ bool DaikinArcClimate::on_receive(remote_base::RemoteReceiveData data) {
         type_ch = '0';
 
       if (abs(data[j]) > 100000) {
-        sprintf(sbuf, "%s%-5d[%c] ", sbuf, data[j] > 0 ? 99999 : -99999, type_ch);
+        sbuf_pos = buf_append_printf(sbuf, sizeof(sbuf), sbuf_pos, "%-5d[%c] ", data[j] > 0 ? 99999 : -99999, type_ch);
       } else {
-        sprintf(sbuf, "%s%-5d[%c] ", sbuf, (int) (round(data[j] / 10.) * 10), type_ch);
+        sbuf_pos =
+            buf_append_printf(sbuf, sizeof(sbuf), sbuf_pos, "%-5d[%c] ", (int) (round(data[j] / 10.) * 10), type_ch);
       }
       if (j + 1 == static_cast<size_t>(data.size())) {
         ESP_LOGD(TAG, "DATA %04x: %s", (j - 8 > 0xffff ? 0 : j - 8), sbuf);

esphome/components/datetime/date_entity.cpp

@@ -106,9 +106,9 @@ DateCall &DateCall::set_date(uint16_t year, uint8_t month, uint8_t day) {
 
 DateCall &DateCall::set_date(ESPTime time) { return this->set_date(time.year, time.month, time.day_of_month); };
 
-DateCall &DateCall::set_date(const std::string &date) {
+DateCall &DateCall::set_date(const char *date, size_t len) {
   ESPTime val{};
-  if (!ESPTime::strptime(date, val)) {
+  if (!ESPTime::strptime(date, len, val)) {
     ESP_LOGE(TAG, "Could not convert the date string to an ESPTime object");
     return *this;
   }

esphome/components/datetime/date_entity.h

@@ -67,7 +67,9 @@ class DateCall {
   void perform();
   DateCall &set_date(uint16_t year, uint8_t month, uint8_t day);
   DateCall &set_date(ESPTime time);
-  DateCall &set_date(const std::string &date);
+  DateCall &set_date(const char *date, size_t len);
+  DateCall &set_date(const char *date) { return this->set_date(date, strlen(date)); }
+  DateCall &set_date(const std::string &date) { return this->set_date(date.c_str(), date.size()); }
 
   DateCall &set_year(uint16_t year) {
     this->year_ = year;

esphome/components/datetime/datetime_entity.cpp

@@ -163,9 +163,9 @@ DateTimeCall &DateTimeCall::set_datetime(ESPTime datetime) {
                             datetime.second);
 };
 
-DateTimeCall &DateTimeCall::set_datetime(const std::string &datetime) {
+DateTimeCall &DateTimeCall::set_datetime(const char *datetime, size_t len) {
   ESPTime val{};
-  if (!ESPTime::strptime(datetime, val)) {
+  if (!ESPTime::strptime(datetime, len, val)) {
     ESP_LOGE(TAG, "Could not convert the time string to an ESPTime object");
     return *this;
   }

esphome/components/datetime/datetime_entity.h

@@ -71,7 +71,11 @@ class DateTimeCall {
   void perform();
   DateTimeCall &set_datetime(uint16_t year, uint8_t month, uint8_t day, uint8_t hour, uint8_t minute, uint8_t second);
   DateTimeCall &set_datetime(ESPTime datetime);
-  DateTimeCall &set_datetime(const std::string &datetime);
+  DateTimeCall &set_datetime(const char *datetime, size_t len);
+  DateTimeCall &set_datetime(const char *datetime) { return this->set_datetime(datetime, strlen(datetime)); }
+  DateTimeCall &set_datetime(const std::string &datetime) {
+    return this->set_datetime(datetime.c_str(), datetime.size());
+  }
   DateTimeCall &set_datetime(time_t epoch_seconds);
 
   DateTimeCall &set_year(uint16_t year) {

esphome/components/datetime/time_entity.cpp

@@ -74,9 +74,9 @@ TimeCall &TimeCall::set_time(uint8_t hour, uint8_t minute, uint8_t second) {
 
 TimeCall &TimeCall::set_time(ESPTime time) { return this->set_time(time.hour, time.minute, time.second); };
 
-TimeCall &TimeCall::set_time(const std::string &time) {
+TimeCall &TimeCall::set_time(const char *time, size_t len) {
   ESPTime val{};
-  if (!ESPTime::strptime(time, val)) {
+  if (!ESPTime::strptime(time, len, val)) {
     ESP_LOGE(TAG, "Could not convert the time string to an ESPTime object");
     return *this;
   }

esphome/components/datetime/time_entity.h

@@ -69,7 +69,9 @@ class TimeCall {
   void perform();
   TimeCall &set_time(uint8_t hour, uint8_t minute, uint8_t second);
   TimeCall &set_time(ESPTime time);
-  TimeCall &set_time(const std::string &time);
+  TimeCall &set_time(const char *time, size_t len);
+  TimeCall &set_time(const char *time) { return this->set_time(time, strlen(time)); }
+  TimeCall &set_time(const std::string &time) { return this->set_time(time.c_str(), time.size()); }
 
   TimeCall &set_hour(uint8_t hour) {
     this->hour_ = hour;

esphome/components/debug/debug_component.cpp

@@ -30,7 +30,7 @@ void DebugComponent::dump_config() {
 
   char device_info_buffer[DEVICE_INFO_BUFFER_SIZE];
   ESP_LOGD(TAG, "ESPHome version %s", ESPHOME_VERSION);
-  size_t pos = buf_append(device_info_buffer, DEVICE_INFO_BUFFER_SIZE, 0, "%s", ESPHOME_VERSION);
+  size_t pos = buf_append_printf(device_info_buffer, DEVICE_INFO_BUFFER_SIZE, 0, "%s", ESPHOME_VERSION);
 
   this->free_heap_ = get_free_heap_();
   ESP_LOGD(TAG, "Free Heap Size: %" PRIu32 " bytes", this->free_heap_);

esphome/components/debug/debug_component.h

@@ -5,12 +5,6 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/macros.h"
 #include <span>
-#include <cstdarg>
-#include <cstdio>
-#include <algorithm>
-#ifdef USE_ESP8266
-#include <pgmspace.h>
-#endif
 
 #ifdef USE_SENSOR
 #include "esphome/components/sensor/sensor.h"
@@ -25,40 +19,7 @@ namespace debug {
 static constexpr size_t DEVICE_INFO_BUFFER_SIZE = 256;
 static constexpr size_t RESET_REASON_BUFFER_SIZE = 128;
 
-#ifdef USE_ESP8266
-// ESP8266: Use vsnprintf_P to keep format strings in flash (PROGMEM)
-// Format strings must be wrapped with PSTR() macro
-inline size_t buf_append_p(char *buf, size_t size, size_t pos, PGM_P fmt, ...) {
-  if (pos >= size) {
-    return size;
-  }
-  va_list args;
-  va_start(args, fmt);
-  int written = vsnprintf_P(buf + pos, size - pos, fmt, args);
-  va_end(args);
-  if (written < 0) {
-    return pos;  // encoding error
-  }
-  return std::min(pos + static_cast<size_t>(written), size);
-}
-#define buf_append(buf, size, pos, fmt, ...) buf_append_p(buf, size, pos, PSTR(fmt), ##__VA_ARGS__)
-#else
-/// Safely append formatted string to buffer, returning new position (capped at size)
-__attribute__((format(printf, 4, 5))) inline size_t buf_append(char *buf, size_t size, size_t pos, const char *fmt,
-                                                               ...) {
-  if (pos >= size) {
-    return size;
-  }
-  va_list args;
-  va_start(args, fmt);
-  int written = vsnprintf(buf + pos, size - pos, fmt, args);
-  va_end(args);
-  if (written < 0) {
-    return pos;  // encoding error
-  }
-  return std::min(pos + static_cast<size_t>(written), size);
-}
-#endif
+// buf_append_printf is now provided by esphome/core/helpers.h
 
 class DebugComponent : public PollingComponent {
  public:
@@ -74,8 +35,11 @@ class DebugComponent : public PollingComponent {
 #ifdef USE_SENSOR
   void set_free_sensor(sensor::Sensor *free_sensor) { free_sensor_ = free_sensor; }
   void set_block_sensor(sensor::Sensor *block_sensor) { block_sensor_ = block_sensor; }
-#if defined(USE_ESP8266) && USE_ARDUINO_VERSION_CODE >= VERSION_CODE(2, 5, 2)
+#if (defined(USE_ESP8266) && USE_ARDUINO_VERSION_CODE >= VERSION_CODE(2, 5, 2)) || defined(USE_ESP32)
   void set_fragmentation_sensor(sensor::Sensor *fragmentation_sensor) { fragmentation_sensor_ = fragmentation_sensor; }
+#endif
+#if defined(USE_ESP32) || defined(USE_LIBRETINY)
+  void set_min_free_sensor(sensor::Sensor *min_free_sensor) { min_free_sensor_ = min_free_sensor; }
 #endif
   void set_loop_time_sensor(sensor::Sensor *loop_time_sensor) { loop_time_sensor_ = loop_time_sensor; }
 #ifdef USE_ESP32
@@ -97,8 +61,11 @@ class DebugComponent : public PollingComponent {
 
   sensor::Sensor *free_sensor_{nullptr};
   sensor::Sensor *block_sensor_{nullptr};
-#if defined(USE_ESP8266) && USE_ARDUINO_VERSION_CODE >= VERSION_CODE(2, 5, 2)
+#if (defined(USE_ESP8266) && USE_ARDUINO_VERSION_CODE >= VERSION_CODE(2, 5, 2)) || defined(USE_ESP32)
   sensor::Sensor *fragmentation_sensor_{nullptr};
+#endif
+#if defined(USE_ESP32) || defined(USE_LIBRETINY)
+  sensor::Sensor *min_free_sensor_{nullptr};
 #endif
   sensor::Sensor *loop_time_sensor_{nullptr};
 #ifdef USE_ESP32

esphome/components/debug/debug_esp32.cpp

@@ -173,8 +173,8 @@ size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE>
   uint32_t flash_size = ESP.getFlashChipSize() / 1024;       // NOLINT
   uint32_t flash_speed = ESP.getFlashChipSpeed() / 1000000;  // NOLINT
   ESP_LOGD(TAG, "Flash Chip: Size=%" PRIu32 "kB Speed=%" PRIu32 "MHz Mode=%s", flash_size, flash_speed, flash_mode);
-  pos = buf_append(buf, size, pos, "|Flash: %" PRIu32 "kB Speed:%" PRIu32 "MHz Mode:%s", flash_size, flash_speed,
-                   flash_mode);
+  pos = buf_append_printf(buf, size, pos, "|Flash: %" PRIu32 "kB Speed:%" PRIu32 "MHz Mode:%s", flash_size, flash_speed,
+                          flash_mode);
 #endif
 
   esp_chip_info_t info;
@@ -182,60 +182,71 @@ size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE>
   const char *model = ESPHOME_VARIANT;
 
   // Build features string
-  pos = buf_append(buf, size, pos, "|Chip: %s Features:", model);
+  pos = buf_append_printf(buf, size, pos, "|Chip: %s Features:", model);
   bool first_feature = true;
   for (const auto &feature : CHIP_FEATURES) {
     if (info.features & feature.bit) {
-      pos = buf_append(buf, size, pos, "%s%s", first_feature ? "" : ", ", feature.name);
+      pos = buf_append_printf(buf, size, pos, "%s%s", first_feature ? "" : ", ", feature.name);
       first_feature = false;
       info.features &= ~feature.bit;
     }
   }
   if (info.features != 0) {
-    pos = buf_append(buf, size, pos, "%sOther:0x%" PRIx32, first_feature ? "" : ", ", info.features);
+    pos = buf_append_printf(buf, size, pos, "%sOther:0x%" PRIx32, first_feature ? "" : ", ", info.features);
   }
   ESP_LOGD(TAG, "Chip: Model=%s, Cores=%u, Revision=%u", model, info.cores, info.revision);
-  pos = buf_append(buf, size, pos, " Cores:%u Revision:%u", info.cores, info.revision);
+  pos = buf_append_printf(buf, size, pos, " Cores:%u Revision:%u", info.cores, info.revision);
 
   uint32_t cpu_freq_mhz = arch_get_cpu_freq_hz() / 1000000;
   ESP_LOGD(TAG, "CPU Frequency: %" PRIu32 " MHz", cpu_freq_mhz);
-  pos = buf_append(buf, size, pos, "|CPU Frequency: %" PRIu32 " MHz", cpu_freq_mhz);
+  pos = buf_append_printf(buf, size, pos, "|CPU Frequency: %" PRIu32 " MHz", cpu_freq_mhz);
 
   // Framework detection
 #ifdef USE_ARDUINO
   ESP_LOGD(TAG, "Framework: Arduino");
-  pos = buf_append(buf, size, pos, "|Framework: Arduino");
+  pos = buf_append_printf(buf, size, pos, "|Framework: Arduino");
 #elif defined(USE_ESP32)
   ESP_LOGD(TAG, "Framework: ESP-IDF");
-  pos = buf_append(buf, size, pos, "|Framework: ESP-IDF");
+  pos = buf_append_printf(buf, size, pos, "|Framework: ESP-IDF");
 #else
   ESP_LOGW(TAG, "Framework: UNKNOWN");
-  pos = buf_append(buf, size, pos, "|Framework: UNKNOWN");
+  pos = buf_append_printf(buf, size, pos, "|Framework: UNKNOWN");
 #endif
 
   ESP_LOGD(TAG, "ESP-IDF Version: %s", esp_get_idf_version());
-  pos = buf_append(buf, size, pos, "|ESP-IDF: %s", esp_get_idf_version());
+  pos = buf_append_printf(buf, size, pos, "|ESP-IDF: %s", esp_get_idf_version());
 
   uint8_t mac[6];
   get_mac_address_raw(mac);
   ESP_LOGD(TAG, "EFuse MAC: %02X:%02X:%02X:%02X:%02X:%02X", mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
-  pos = buf_append(buf, size, pos, "|EFuse MAC: %02X:%02X:%02X:%02X:%02X:%02X", mac[0], mac[1], mac[2], mac[3], mac[4],
-                   mac[5]);
+  pos = buf_append_printf(buf, size, pos, "|EFuse MAC: %02X:%02X:%02X:%02X:%02X:%02X", mac[0], mac[1], mac[2], mac[3],
+                          mac[4], mac[5]);
 
   char reason_buffer[RESET_REASON_BUFFER_SIZE];
   const char *reset_reason = get_reset_reason_(std::span<char, RESET_REASON_BUFFER_SIZE>(reason_buffer));
-  pos = buf_append(buf, size, pos, "|Reset: %s", reset_reason);
+  pos = buf_append_printf(buf, size, pos, "|Reset: %s", reset_reason);
 
   const char *wakeup_cause = get_wakeup_cause_(std::span<char, RESET_REASON_BUFFER_SIZE>(reason_buffer));
-  pos = buf_append(buf, size, pos, "|Wakeup: %s", wakeup_cause);
+  pos = buf_append_printf(buf, size, pos, "|Wakeup: %s", wakeup_cause);
 
   return pos;
 }
 
 void DebugComponent::update_platform_() {
 #ifdef USE_SENSOR
+  uint32_t max_alloc = heap_caps_get_largest_free_block(MALLOC_CAP_INTERNAL);
   if (this->block_sensor_ != nullptr) {
-    this->block_sensor_->publish_state(heap_caps_get_largest_free_block(MALLOC_CAP_INTERNAL));
+    this->block_sensor_->publish_state(max_alloc);
+  }
+  if (this->min_free_sensor_ != nullptr) {
+    this->min_free_sensor_->publish_state(heap_caps_get_minimum_free_size(MALLOC_CAP_INTERNAL));
+  }
+  if (this->fragmentation_sensor_ != nullptr) {
+    uint32_t free_heap = heap_caps_get_free_size(MALLOC_CAP_INTERNAL);
+    if (free_heap > 0) {
+      float fragmentation = 100.0f - (100.0f * max_alloc / free_heap);
+      this->fragmentation_sensor_->publish_state(fragmentation);
+    }
   }
   if (this->psram_sensor_ != nullptr) {
     this->psram_sensor_->publish_state(heap_caps_get_free_size(MALLOC_CAP_SPIRAM));

esphome/components/debug/debug_esp8266.cpp

@@ -3,21 +3,80 @@
 #include "esphome/core/log.h"
 #include <Esp.h>
 
+extern "C" {
+#include <user_interface.h>
+
+// Global reset info struct populated by SDK at boot
+extern struct rst_info resetInfo;
+
+// Core version - either a string pointer or a version number to format as hex
+extern uint32_t core_version;
+extern const char *core_release;
+}
+
 namespace esphome {
 namespace debug {
 
 static const char *const TAG = "debug";
 
+// Get reset reason string from reason code (no heap allocation)
+// Returns LogString* pointing to flash (PROGMEM) on ESP8266
+static const LogString *get_reset_reason_str(uint32_t reason) {
+  switch (reason) {
+    case REASON_DEFAULT_RST:
+      return LOG_STR("Power On");
+    case REASON_WDT_RST:
+      return LOG_STR("Hardware Watchdog");
+    case REASON_EXCEPTION_RST:
+      return LOG_STR("Exception");
+    case REASON_SOFT_WDT_RST:
+      return LOG_STR("Software Watchdog");
+    case REASON_SOFT_RESTART:
+      return LOG_STR("Software/System restart");
+    case REASON_DEEP_SLEEP_AWAKE:
+      return LOG_STR("Deep-Sleep Wake");
+    case REASON_EXT_SYS_RST:
+      return LOG_STR("External System");
+    default:
+      return LOG_STR("Unknown");
+  }
+}
+
+// Size for core version hex buffer
+static constexpr size_t CORE_VERSION_BUFFER_SIZE = 12;
+
+// Get core version string (no heap allocation)
+// Returns either core_release directly or formats core_version as hex into provided buffer
+static const char *get_core_version_str(std::span<char, CORE_VERSION_BUFFER_SIZE> buffer) {
+  if (core_release != nullptr) {
+    return core_release;
+  }
+  snprintf_P(buffer.data(), CORE_VERSION_BUFFER_SIZE, PSTR("%08x"), core_version);
+  return buffer.data();
+}
+
+// Size for reset info buffer
+static constexpr size_t RESET_INFO_BUFFER_SIZE = 200;
+
+// Get detailed reset info string (no heap allocation)
+// For watchdog/exception resets, includes detailed exception info
+static const char *get_reset_info_str(std::span<char, RESET_INFO_BUFFER_SIZE> buffer, uint32_t reason) {
+  if (reason >= REASON_WDT_RST && reason <= REASON_SOFT_WDT_RST) {
+    snprintf_P(buffer.data(), RESET_INFO_BUFFER_SIZE,
+               PSTR("Fatal exception:%d flag:%d (%s) epc1:0x%08x epc2:0x%08x epc3:0x%08x excvaddr:0x%08x depc:0x%08x"),
+               static_cast<int>(resetInfo.exccause), static_cast<int>(reason),
+               LOG_STR_ARG(get_reset_reason_str(reason)), resetInfo.epc1, resetInfo.epc2, resetInfo.epc3,
+               resetInfo.excvaddr, resetInfo.depc);
+    return buffer.data();
+  }
+  return LOG_STR_ARG(get_reset_reason_str(reason));
+}
+
 const char *DebugComponent::get_reset_reason_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) {
-  char *buf = buffer.data();
-#if !defined(CLANG_TIDY)
-  String reason = ESP.getResetReason();  // NOLINT
-  snprintf_P(buf, RESET_REASON_BUFFER_SIZE, PSTR("%s"), reason.c_str());
-  return buf;
-#else
-  buf[0] = '\0';
-  return buf;
-#endif
+  // Copy from flash to provided buffer
+  strncpy_P(buffer.data(), (PGM_P) get_reset_reason_str(resetInfo.reason), RESET_REASON_BUFFER_SIZE - 1);
+  buffer[RESET_REASON_BUFFER_SIZE - 1] = '\0';
+  return buffer.data();
 }
 
 const char *DebugComponent::get_wakeup_cause_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) {
@@ -33,37 +92,42 @@ size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE>
   constexpr size_t size = DEVICE_INFO_BUFFER_SIZE;
   char *buf = buffer.data();
 
-  const char *flash_mode;
+  const LogString *flash_mode;
   switch (ESP.getFlashChipMode()) {  // NOLINT(readability-static-accessed-through-instance)
     case FM_QIO:
-      flash_mode = "QIO";
+      flash_mode = LOG_STR("QIO");
       break;
     case FM_QOUT:
-      flash_mode = "QOUT";
+      flash_mode = LOG_STR("QOUT");
       break;
     case FM_DIO:
-      flash_mode = "DIO";
+      flash_mode = LOG_STR("DIO");
       break;
     case FM_DOUT:
-      flash_mode = "DOUT";
+      flash_mode = LOG_STR("DOUT");
       break;
     default:
-      flash_mode = "UNKNOWN";
+      flash_mode = LOG_STR("UNKNOWN");
   }
-  uint32_t flash_size = ESP.getFlashChipSize() / 1024;       // NOLINT
-  uint32_t flash_speed = ESP.getFlashChipSpeed() / 1000000;  // NOLINT
-  ESP_LOGD(TAG, "Flash Chip: Size=%" PRIu32 "kB Speed=%" PRIu32 "MHz Mode=%s", flash_size, flash_speed, flash_mode);
-  pos = buf_append(buf, size, pos, "|Flash: %" PRIu32 "kB Speed:%" PRIu32 "MHz Mode:%s", flash_size, flash_speed,
-                   flash_mode);
+  uint32_t flash_size = ESP.getFlashChipSize() / 1024;       // NOLINT(readability-static-accessed-through-instance)
+  uint32_t flash_speed = ESP.getFlashChipSpeed() / 1000000;  // NOLINT(readability-static-accessed-through-instance)
+  ESP_LOGD(TAG, "Flash Chip: Size=%" PRIu32 "kB Speed=%" PRIu32 "MHz Mode=%s", flash_size, flash_speed,
+           LOG_STR_ARG(flash_mode));
+  pos = buf_append_printf(buf, size, pos, "|Flash: %" PRIu32 "kB Speed:%" PRIu32 "MHz Mode:%s", flash_size, flash_speed,
+                          LOG_STR_ARG(flash_mode));
 
-#if !defined(CLANG_TIDY)
   char reason_buffer[RESET_REASON_BUFFER_SIZE];
-  const char *reset_reason = get_reset_reason_(std::span<char, RESET_REASON_BUFFER_SIZE>(reason_buffer));
+  const char *reset_reason = get_reset_reason_(reason_buffer);
+  char core_version_buffer[CORE_VERSION_BUFFER_SIZE];
+  char reset_info_buffer[RESET_INFO_BUFFER_SIZE];
+  // NOLINTBEGIN(readability-static-accessed-through-instance)
   uint32_t chip_id = ESP.getChipId();
   uint8_t boot_version = ESP.getBootVersion();
   uint8_t boot_mode = ESP.getBootMode();
   uint8_t cpu_freq = ESP.getCpuFreqMHz();
   uint32_t flash_chip_id = ESP.getFlashChipId();
+  const char *sdk_version = ESP.getSdkVersion();
+  // NOLINTEND(readability-static-accessed-through-instance)
 
   ESP_LOGD(TAG,
            "Chip ID: 0x%08" PRIX32 "\n"
@@ -74,19 +138,18 @@ size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE>
            "Flash Chip ID=0x%08" PRIX32 "\n"
            "Reset Reason: %s\n"
            "Reset Info: %s",
-           chip_id, ESP.getSdkVersion(), ESP.getCoreVersion().c_str(), boot_version, boot_mode, cpu_freq, flash_chip_id,
-           reset_reason, ESP.getResetInfo().c_str());
+           chip_id, sdk_version, get_core_version_str(core_version_buffer), boot_version, boot_mode, cpu_freq,
+           flash_chip_id, reset_reason, get_reset_info_str(reset_info_buffer, resetInfo.reason));
 
-  pos = buf_append(buf, size, pos, "|Chip: 0x%08" PRIX32, chip_id);
-  pos = buf_append(buf, size, pos, "|SDK: %s", ESP.getSdkVersion());
-  pos = buf_append(buf, size, pos, "|Core: %s", ESP.getCoreVersion().c_str());
-  pos = buf_append(buf, size, pos, "|Boot: %u", boot_version);
-  pos = buf_append(buf, size, pos, "|Mode: %u", boot_mode);
-  pos = buf_append(buf, size, pos, "|CPU: %u", cpu_freq);
-  pos = buf_append(buf, size, pos, "|Flash: 0x%08" PRIX32, flash_chip_id);
-  pos = buf_append(buf, size, pos, "|Reset: %s", reset_reason);
-  pos = buf_append(buf, size, pos, "|%s", ESP.getResetInfo().c_str());
-#endif
+  pos = buf_append_printf(buf, size, pos, "|Chip: 0x%08" PRIX32, chip_id);
+  pos = buf_append_printf(buf, size, pos, "|SDK: %s", sdk_version);
+  pos = buf_append_printf(buf, size, pos, "|Core: %s", get_core_version_str(core_version_buffer));
+  pos = buf_append_printf(buf, size, pos, "|Boot: %u", boot_version);
+  pos = buf_append_printf(buf, size, pos, "|Mode: %u", boot_mode);
+  pos = buf_append_printf(buf, size, pos, "|CPU: %u", cpu_freq);
+  pos = buf_append_printf(buf, size, pos, "|Flash: 0x%08" PRIX32, flash_chip_id);
+  pos = buf_append_printf(buf, size, pos, "|Reset: %s", reset_reason);
+  pos = buf_append_printf(buf, size, pos, "|%s", get_reset_info_str(reset_info_buffer, resetInfo.reason));
 
   return pos;
 }

esphome/components/debug/debug_libretiny.cpp

@@ -36,12 +36,12 @@ size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE>
            lt_get_version(), lt_cpu_get_model_name(), lt_cpu_get_model(), lt_cpu_get_freq_mhz(), mac_id,
            lt_get_board_code(), flash_kib, ram_kib, reset_reason);
 
-  pos = buf_append(buf, size, pos, "|Version: %s", LT_BANNER_STR + 10);
-  pos = buf_append(buf, size, pos, "|Reset Reason: %s", reset_reason);
-  pos = buf_append(buf, size, pos, "|Chip Name: %s", lt_cpu_get_model_name());
-  pos = buf_append(buf, size, pos, "|Chip ID: 0x%06" PRIX32, mac_id);
-  pos = buf_append(buf, size, pos, "|Flash: %" PRIu32 " KiB", flash_kib);
-  pos = buf_append(buf, size, pos, "|RAM: %" PRIu32 " KiB", ram_kib);
+  pos = buf_append_printf(buf, size, pos, "|Version: %s", LT_BANNER_STR + 10);
+  pos = buf_append_printf(buf, size, pos, "|Reset Reason: %s", reset_reason);
+  pos = buf_append_printf(buf, size, pos, "|Chip Name: %s", lt_cpu_get_model_name());
+  pos = buf_append_printf(buf, size, pos, "|Chip ID: 0x%06" PRIX32, mac_id);
+  pos = buf_append_printf(buf, size, pos, "|Flash: %" PRIu32 " KiB", flash_kib);
+  pos = buf_append_printf(buf, size, pos, "|RAM: %" PRIu32 " KiB", ram_kib);
 
   return pos;
 }
@@ -51,6 +51,9 @@ void DebugComponent::update_platform_() {
   if (this->block_sensor_ != nullptr) {
     this->block_sensor_->publish_state(lt_heap_get_max_alloc());
   }
+  if (this->min_free_sensor_ != nullptr) {
+    this->min_free_sensor_->publish_state(lt_heap_get_min_free());
+  }
 #endif
 }
 

esphome/components/debug/debug_rp2040.cpp

@@ -19,7 +19,7 @@ size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE>
 
   uint32_t cpu_freq = rp2040.f_cpu();
   ESP_LOGD(TAG, "CPU Frequency: %" PRIu32, cpu_freq);
-  pos = buf_append(buf, size, pos, "|CPU Frequency: %" PRIu32, cpu_freq);
+  pos = buf_append_printf(buf, size, pos, "|CPU Frequency: %" PRIu32, cpu_freq);
 
   return pos;
 }

esphome/components/debug/debug_zephyr.cpp

@@ -20,9 +20,9 @@ static size_t append_reset_reason(char *buf, size_t size, size_t pos, bool set,
     return pos;
   }
   if (pos > 0) {
-    pos = buf_append(buf, size, pos, ", ");
+    pos = buf_append_printf(buf, size, pos, ", ");
   }
-  return buf_append(buf, size, pos, "%s", reason);
+  return buf_append_printf(buf, size, pos, "%s", reason);
 }
 
 static inline uint32_t read_mem_u32(uintptr_t addr) {
@@ -140,7 +140,7 @@ size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE>
   const char *supply_status =
       (nrf_power_mainregstatus_get(NRF_POWER) == NRF_POWER_MAINREGSTATUS_NORMAL) ? "Normal voltage." : "High voltage.";
   ESP_LOGD(TAG, "Main supply status: %s", supply_status);
-  pos = buf_append(buf, size, pos, "|Main supply status: %s", supply_status);
+  pos = buf_append_printf(buf, size, pos, "|Main supply status: %s", supply_status);
 
   // Regulator stage 0
   if (nrf_power_mainregstatus_get(NRF_POWER) == NRF_POWER_MAINREGSTATUS_HIGH) {
@@ -172,16 +172,16 @@ size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE>
         reg0_voltage = "???V";
     }
     ESP_LOGD(TAG, "Regulator stage 0: %s, %s", reg0_type, reg0_voltage);
-    pos = buf_append(buf, size, pos, "|Regulator stage 0: %s, %s", reg0_type, reg0_voltage);
+    pos = buf_append_printf(buf, size, pos, "|Regulator stage 0: %s, %s", reg0_type, reg0_voltage);
   } else {
     ESP_LOGD(TAG, "Regulator stage 0: disabled");
-    pos = buf_append(buf, size, pos, "|Regulator stage 0: disabled");
+    pos = buf_append_printf(buf, size, pos, "|Regulator stage 0: disabled");
   }
 
   // Regulator stage 1
   const char *reg1_type = nrf_power_dcdcen_get(NRF_POWER) ? "DC/DC" : "LDO";
   ESP_LOGD(TAG, "Regulator stage 1: %s", reg1_type);
-  pos = buf_append(buf, size, pos, "|Regulator stage 1: %s", reg1_type);
+  pos = buf_append_printf(buf, size, pos, "|Regulator stage 1: %s", reg1_type);
 
   // USB power state
   const char *usb_state;
@@ -195,7 +195,7 @@ size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE>
     usb_state = "disconnected";
   }
   ESP_LOGD(TAG, "USB power state: %s", usb_state);
-  pos = buf_append(buf, size, pos, "|USB power state: %s", usb_state);
+  pos = buf_append_printf(buf, size, pos, "|USB power state: %s", usb_state);
 
   // Power-fail comparator
   bool enabled;
@@ -300,14 +300,14 @@ size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE>
           break;
       }
       ESP_LOGD(TAG, "Power-fail comparator: %s, VDDH: %s", pof_voltage, vddh_voltage);
-      pos = buf_append(buf, size, pos, "|Power-fail comparator: %s, VDDH: %s", pof_voltage, vddh_voltage);
+      pos = buf_append_printf(buf, size, pos, "|Power-fail comparator: %s, VDDH: %s", pof_voltage, vddh_voltage);
     } else {
       ESP_LOGD(TAG, "Power-fail comparator: %s", pof_voltage);
-      pos = buf_append(buf, size, pos, "|Power-fail comparator: %s", pof_voltage);
+      pos = buf_append_printf(buf, size, pos, "|Power-fail comparator: %s", pof_voltage);
     }
   } else {
     ESP_LOGD(TAG, "Power-fail comparator: disabled");
-    pos = buf_append(buf, size, pos, "|Power-fail comparator: disabled");
+    pos = buf_append_printf(buf, size, pos, "|Power-fail comparator: disabled");
   }
 
   auto package = [](uint32_t value) {

esphome/components/debug/sensor.py

@@ -11,6 +11,9 @@ from esphome.const import (
     ENTITY_CATEGORY_DIAGNOSTIC,
     ICON_COUNTER,
     ICON_TIMER,
+    PLATFORM_BK72XX,
+    PLATFORM_LN882X,
+    PLATFORM_RTL87XX,
     UNIT_BYTES,
     UNIT_HERTZ,
     UNIT_MILLISECOND,
@@ -25,6 +28,7 @@ from . import (  # noqa: F401  pylint: disable=unused-import
 
 DEPENDENCIES = ["debug"]
 
+CONF_MIN_FREE = "min_free"
 CONF_PSRAM = "psram"
 
 CONFIG_SCHEMA = {
@@ -42,8 +46,14 @@ CONFIG_SCHEMA = {
         entity_category=ENTITY_CATEGORY_DIAGNOSTIC,
     ),
     cv.Optional(CONF_FRAGMENTATION): cv.All(
-        cv.only_on_esp8266,
-        cv.require_framework_version(esp8266_arduino=cv.Version(2, 5, 2)),
+        cv.Any(
+            cv.All(
+                cv.only_on_esp8266,
+                cv.require_framework_version(esp8266_arduino=cv.Version(2, 5, 2)),
+            ),
+            cv.only_on_esp32,
+            msg="This feature is only available on ESP8266 (Arduino 2.5.2+) and ESP32",
+        ),
         sensor.sensor_schema(
             unit_of_measurement=UNIT_PERCENT,
             icon=ICON_COUNTER,
@@ -51,6 +61,19 @@ CONFIG_SCHEMA = {
             entity_category=ENTITY_CATEGORY_DIAGNOSTIC,
         ),
     ),
+    cv.Optional(CONF_MIN_FREE): cv.All(
+        cv.Any(
+            cv.only_on_esp32,
+            cv.only_on([PLATFORM_BK72XX, PLATFORM_LN882X, PLATFORM_RTL87XX]),
+            msg="This feature is only available on ESP32 and LibreTiny (BK72xx, LN882x, RTL87xx)",
+        ),
+        sensor.sensor_schema(
+            unit_of_measurement=UNIT_BYTES,
+            icon=ICON_COUNTER,
+            accuracy_decimals=0,
+            entity_category=ENTITY_CATEGORY_DIAGNOSTIC,
+        ),
+    ),
     cv.Optional(CONF_LOOP_TIME): sensor.sensor_schema(
         unit_of_measurement=UNIT_MILLISECOND,
         icon=ICON_TIMER,
@@ -93,6 +116,10 @@ async def to_code(config):
         sens = await sensor.new_sensor(fragmentation_conf)
         cg.add(debug_component.set_fragmentation_sensor(sens))
 
+    if min_free_conf := config.get(CONF_MIN_FREE):
+        sens = await sensor.new_sensor(min_free_conf)
+        cg.add(debug_component.set_min_free_sensor(sens))
+
     if loop_time_conf := config.get(CONF_LOOP_TIME):
         sens = await sensor.new_sensor(loop_time_conf)
         cg.add(debug_component.set_loop_time_sensor(sens))

esphome/components/dfrobot_sen0395/commands.cpp

@@ -127,7 +127,9 @@ DetRangeCfgCommand::DetRangeCfgCommand(float min1, float max1, float min2, float
     this->min2_ = min2 = this->max2_ = max2 = this->min3_ = min3 = this->max3_ = max3 = this->min4_ = min4 =
         this->max4_ = max4 = -1;
 
-    this->cmd_ = str_sprintf("detRangeCfg -1 %.0f %.0f", min1 / 0.15, max1 / 0.15);
+    char buf[72];  // max 72: "detRangeCfg -1 "(15) + 8 * (float(5) + space(1)) + null
+    snprintf(buf, sizeof(buf), "detRangeCfg -1 %.0f %.0f", min1 / 0.15, max1 / 0.15);
+    this->cmd_ = buf;
   } else if (min3 < 0 || max3 < 0) {
     this->min1_ = min1 = round(min1 / 0.15) * 0.15;
     this->max1_ = max1 = round(max1 / 0.15) * 0.15;
@@ -135,7 +137,10 @@ DetRangeCfgCommand::DetRangeCfgCommand(float min1, float max1, float min2, float
     this->max2_ = max2 = round(max2 / 0.15) * 0.15;
     this->min3_ = min3 = this->max3_ = max3 = this->min4_ = min4 = this->max4_ = max4 = -1;
 
-    this->cmd_ = str_sprintf("detRangeCfg -1 %.0f %.0f %.0f %.0f", min1 / 0.15, max1 / 0.15, min2 / 0.15, max2 / 0.15);
+    char buf[72];  // max 72: "detRangeCfg -1 "(15) + 8 * (float(5) + space(1)) + null
+    snprintf(buf, sizeof(buf), "detRangeCfg -1 %.0f %.0f %.0f %.0f", min1 / 0.15, max1 / 0.15, min2 / 0.15,
+             max2 / 0.15);
+    this->cmd_ = buf;
   } else if (min4 < 0 || max4 < 0) {
     this->min1_ = min1 = round(min1 / 0.15) * 0.15;
     this->max1_ = max1 = round(max1 / 0.15) * 0.15;
@@ -145,9 +150,10 @@ DetRangeCfgCommand::DetRangeCfgCommand(float min1, float max1, float min2, float
     this->max3_ = max3 = round(max3 / 0.15) * 0.15;
     this->min4_ = min4 = this->max4_ = max4 = -1;
 
-    this->cmd_ = str_sprintf("detRangeCfg -1 "
-                             "%.0f %.0f %.0f %.0f %.0f %.0f",
-                             min1 / 0.15, max1 / 0.15, min2 / 0.15, max2 / 0.15, min3 / 0.15, max3 / 0.15);
+    char buf[72];  // max 72: "detRangeCfg -1 "(15) + 8 * (float(5) + space(1)) + null
+    snprintf(buf, sizeof(buf), "detRangeCfg -1 %.0f %.0f %.0f %.0f %.0f %.0f", min1 / 0.15, max1 / 0.15, min2 / 0.15,
+             max2 / 0.15, min3 / 0.15, max3 / 0.15);
+    this->cmd_ = buf;
   } else {
     this->min1_ = min1 = round(min1 / 0.15) * 0.15;
     this->max1_ = max1 = round(max1 / 0.15) * 0.15;
@@ -158,10 +164,10 @@ DetRangeCfgCommand::DetRangeCfgCommand(float min1, float max1, float min2, float
     this->min4_ = min4 = round(min4 / 0.15) * 0.15;
     this->max4_ = max4 = round(max4 / 0.15) * 0.15;
 
-    this->cmd_ = str_sprintf("detRangeCfg -1 "
-                             "%.0f %.0f %.0f %.0f %.0f %.0f %.0f %.0f",
-                             min1 / 0.15, max1 / 0.15, min2 / 0.15, max2 / 0.15, min3 / 0.15, max3 / 0.15, min4 / 0.15,
-                             max4 / 0.15);
+    char buf[72];  // max 72: "detRangeCfg -1 "(15) + 8 * (float(5) + space(1)) + null
+    snprintf(buf, sizeof(buf), "detRangeCfg -1 %.0f %.0f %.0f %.0f %.0f %.0f %.0f %.0f", min1 / 0.15, max1 / 0.15,
+             min2 / 0.15, max2 / 0.15, min3 / 0.15, max3 / 0.15, min4 / 0.15, max4 / 0.15);
+    this->cmd_ = buf;
   }
 
   this->min1_ = min1;
@@ -203,7 +209,10 @@ SetLatencyCommand::SetLatencyCommand(float delay_after_detection, float delay_af
   delay_after_disappear = std::round(delay_after_disappear / 0.025f) * 0.025f;
   this->delay_after_detection_ = clamp(delay_after_detection, 0.0f, 1638.375f);
   this->delay_after_disappear_ = clamp(delay_after_disappear, 0.0f, 1638.375f);
-  this->cmd_ = str_sprintf("setLatency %.03f %.03f", this->delay_after_detection_, this->delay_after_disappear_);
+  // max 32: "setLatency "(11) + float(8) + " "(1) + float(8) + null, rounded to 32
+  char buf[32];
+  snprintf(buf, sizeof(buf), "setLatency %.03f %.03f", this->delay_after_detection_, this->delay_after_disappear_);
+  this->cmd_ = buf;
 };
 
 uint8_t SetLatencyCommand::on_message(std::string &message) {

esphome/components/dfrobot_sen0395/commands.h

@@ -75,8 +75,8 @@ class SetLatencyCommand : public Command {
 class SensorCfgStartCommand : public Command {
  public:
   SensorCfgStartCommand(bool startup_mode) : startup_mode_(startup_mode) {
-    char tmp_cmd[20] = {0};
-    sprintf(tmp_cmd, "sensorCfgStart %d", startup_mode);
+    char tmp_cmd[20];  // "sensorCfgStart " (15) + "0/1" (1) + null = 17
+    buf_append_printf(tmp_cmd, sizeof(tmp_cmd), 0, "sensorCfgStart %d", startup_mode);
     cmd_ = std::string(tmp_cmd);
   }
   uint8_t on_message(std::string &message) override;
@@ -142,8 +142,8 @@ class SensitivityCommand : public Command {
   SensitivityCommand(uint8_t sensitivity) : sensitivity_(sensitivity) {
     if (sensitivity > 9)
       sensitivity_ = sensitivity = 9;
-    char tmp_cmd[20] = {0};
-    sprintf(tmp_cmd, "setSensitivity %d", sensitivity);
+    char tmp_cmd[20];  // "setSensitivity " (15) + "0-9" (1) + null = 17
+    buf_append_printf(tmp_cmd, sizeof(tmp_cmd), 0, "setSensitivity %d", sensitivity);
     cmd_ = std::string(tmp_cmd);
   };
   uint8_t on_message(std::string &message) override;

esphome/components/dsmr/__init__.py

@@ -25,29 +25,13 @@ dsmr_ns = cg.esphome_ns.namespace("esphome::dsmr")
 Dsmr = dsmr_ns.class_("Dsmr", cg.Component, uart.UARTDevice)
 
 
-def _validate_key(value):
-    value = cv.string_strict(value)
-    parts = [value[i : i + 2] for i in range(0, len(value), 2)]
-    if len(parts) != 16:
-        raise cv.Invalid("Decryption key must consist of 16 hexadecimal numbers")
-    parts_int = []
-    if any(len(part) != 2 for part in parts):
-        raise cv.Invalid("Decryption key must be format XX")
-    for part in parts:
-        try:
-            parts_int.append(int(part, 16))
-        except ValueError:
-            # pylint: disable=raise-missing-from
-            raise cv.Invalid("Decryption key must be hex values from 00 to FF")
-
-    return "".join(f"{part:02X}" for part in parts_int)
-
-
 CONFIG_SCHEMA = cv.All(
     cv.Schema(
         {
             cv.GenerateID(): cv.declare_id(Dsmr),
-            cv.Optional(CONF_DECRYPTION_KEY): _validate_key,
+            cv.Optional(CONF_DECRYPTION_KEY): lambda value: cv.bind_key(
+                value, name="Decryption key"
+            ),
             cv.Optional(CONF_CRC_CHECK, default=True): cv.boolean,
             cv.Optional(CONF_GAS_MBUS_ID, default=1): cv.int_,
             cv.Optional(CONF_WATER_MBUS_ID, default=2): cv.int_,

esphome/components/dsmr/dsmr.cpp

@@ -1,4 +1,5 @@
 #include "dsmr.h"
+#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
 #include <AES.h>
@@ -294,8 +295,8 @@ void Dsmr::dump_config() {
   DSMR_TEXT_SENSOR_LIST(DSMR_LOG_TEXT_SENSOR, )
 }
 
-void Dsmr::set_decryption_key(const std::string &decryption_key) {
-  if (decryption_key.empty()) {
+void Dsmr::set_decryption_key(const char *decryption_key) {
+  if (decryption_key == nullptr || decryption_key[0] == '\0') {
     ESP_LOGI(TAG, "Disabling decryption");
     this->decryption_key_.clear();
     if (this->crypt_telegram_ != nullptr) {
@@ -305,21 +306,15 @@ void Dsmr::set_decryption_key(const std::string &decryption_key) {
     return;
   }
 
-  if (decryption_key.length() != 32) {
-    ESP_LOGE(TAG, "Error, decryption key must be 32 character long");
+  if (!parse_hex(decryption_key, this->decryption_key_, 16)) {
+    ESP_LOGE(TAG, "Error, decryption key must be 32 hex characters");
+    this->decryption_key_.clear();
     return;
   }
-  this->decryption_key_.clear();
 
   ESP_LOGI(TAG, "Decryption key is set");
   // Verbose level prints decryption key
-  ESP_LOGV(TAG, "Using decryption key: %s", decryption_key.c_str());
-
-  char temp[3] = {0};
-  for (int i = 0; i < 16; i++) {
-    strncpy(temp, &(decryption_key.c_str()[i * 2]), 2);
-    this->decryption_key_.push_back(std::strtoul(temp, nullptr, 16));
-  }
+  ESP_LOGV(TAG, "Using decryption key: %s", decryption_key);
 
   if (this->crypt_telegram_ == nullptr) {
     this->crypt_telegram_ = new uint8_t[this->max_telegram_len_];  // NOLINT

esphome/components/dsmr/dsmr.h

@@ -63,7 +63,7 @@ class Dsmr : public Component, public uart::UARTDevice {
 
   void dump_config() override;
 
-  void set_decryption_key(const std::string &decryption_key);
+  void set_decryption_key(const char *decryption_key);
   void set_max_telegram_length(size_t length) { this->max_telegram_len_ = length; }
   void set_request_pin(GPIOPin *request_pin) { this->request_pin_ = request_pin; }
   void set_request_interval(uint32_t interval) { this->request_interval_ = interval; }

esphome/components/esp32/__init__.py

@@ -34,6 +34,7 @@ from esphome.const import (
     KEY_CORE,
     KEY_FRAMEWORK_VERSION,
     KEY_NAME,
+    KEY_NATIVE_IDF,
     KEY_TARGET_FRAMEWORK,
     KEY_TARGET_PLATFORM,
     PLATFORM_ESP32,
@@ -53,6 +54,7 @@ from .const import (  # noqa
     KEY_COMPONENTS,
     KEY_ESP32,
     KEY_EXTRA_BUILD_FILES,
+    KEY_FLASH_SIZE,
     KEY_PATH,
     KEY_REF,
     KEY_REPO,
@@ -199,6 +201,7 @@ def set_core_data(config):
     )
 
     CORE.data[KEY_ESP32][KEY_BOARD] = config[CONF_BOARD]
+    CORE.data[KEY_ESP32][KEY_FLASH_SIZE] = config[CONF_FLASH_SIZE]
     CORE.data[KEY_ESP32][KEY_VARIANT] = variant
     CORE.data[KEY_ESP32][KEY_EXTRA_BUILD_FILES] = {}
 
@@ -962,12 +965,54 @@ async def _add_yaml_idf_components(components: list[ConfigType]):
 
 
 async def to_code(config):
-    cg.add_platformio_option("board", config[CONF_BOARD])
-    cg.add_platformio_option("board_upload.flash_size", config[CONF_FLASH_SIZE])
-    cg.add_platformio_option(
-        "board_upload.maximum_size",
-        int(config[CONF_FLASH_SIZE].removesuffix("MB")) * 1024 * 1024,
-    )
+    framework_ver: cv.Version = CORE.data[KEY_CORE][KEY_FRAMEWORK_VERSION]
+    conf = config[CONF_FRAMEWORK]
+
+    # Check if using native ESP-IDF build (--native-idf)
+    use_platformio = not CORE.data.get(KEY_NATIVE_IDF, False)
+    if use_platformio:
+        # Clear IDF environment variables to avoid conflicts with PlatformIO's ESP-IDF
+        # but keep them when using --native-idf for native ESP-IDF builds
+        for clean_var in ("IDF_PATH", "IDF_TOOLS_PATH"):
+            os.environ.pop(clean_var, None)
+
+        cg.add_platformio_option("lib_ldf_mode", "off")
+        cg.add_platformio_option("lib_compat_mode", "strict")
+        cg.add_platformio_option("platform", conf[CONF_PLATFORM_VERSION])
+        cg.add_platformio_option("board", config[CONF_BOARD])
+        cg.add_platformio_option("board_upload.flash_size", config[CONF_FLASH_SIZE])
+        cg.add_platformio_option(
+            "board_upload.maximum_size",
+            int(config[CONF_FLASH_SIZE].removesuffix("MB")) * 1024 * 1024,
+        )
+
+        if CONF_SOURCE in conf:
+            cg.add_platformio_option("platform_packages", [conf[CONF_SOURCE]])
+
+        add_extra_script(
+            "pre",
+            "pre_build.py",
+            Path(__file__).parent / "pre_build.py.script",
+        )
+
+        add_extra_script(
+            "post",
+            "post_build.py",
+            Path(__file__).parent / "post_build.py.script",
+        )
+
+        # In testing mode, add IRAM fix script to allow linking grouped component tests
+        # Similar to ESP8266's approach but for ESP-IDF
+        if CORE.testing_mode:
+            cg.add_build_flag("-DESPHOME_TESTING_MODE")
+            add_extra_script(
+                "pre",
+                "iram_fix.py",
+                Path(__file__).parent / "iram_fix.py.script",
+            )
+    else:
+        cg.add_build_flag("-Wno-error=format")
+
     cg.set_cpp_standard("gnu++20")
     cg.add_build_flag("-DUSE_ESP32")
     cg.add_build_flag("-Wl,-z,noexecstack")
@@ -977,79 +1022,49 @@ async def to_code(config):
     cg.add_define("ESPHOME_VARIANT", VARIANT_FRIENDLY[variant])
     cg.add_define(ThreadModel.MULTI_ATOMICS)
 
-    cg.add_platformio_option("lib_ldf_mode", "off")
-    cg.add_platformio_option("lib_compat_mode", "strict")
-
-    framework_ver: cv.Version = CORE.data[KEY_CORE][KEY_FRAMEWORK_VERSION]
-
-    conf = config[CONF_FRAMEWORK]
-    cg.add_platformio_option("platform", conf[CONF_PLATFORM_VERSION])
-    if CONF_SOURCE in conf:
-        cg.add_platformio_option("platform_packages", [conf[CONF_SOURCE]])
-
     if conf[CONF_ADVANCED][CONF_IGNORE_EFUSE_CUSTOM_MAC]:
         cg.add_define("USE_ESP32_IGNORE_EFUSE_CUSTOM_MAC")
 
-    for clean_var in ("IDF_PATH", "IDF_TOOLS_PATH"):
-        os.environ.pop(clean_var, None)
-
     # Set the location of the IDF component manager cache
     os.environ["IDF_COMPONENT_CACHE_PATH"] = str(
         CORE.relative_internal_path(".espressif")
     )
 
-    add_extra_script(
-        "pre",
-        "pre_build.py",
-        Path(__file__).parent / "pre_build.py.script",
-    )
-
-    add_extra_script(
-        "post",
-        "post_build.py",
-        Path(__file__).parent / "post_build.py.script",
-    )
-
-    # In testing mode, add IRAM fix script to allow linking grouped component tests
-    # Similar to ESP8266's approach but for ESP-IDF
-    if CORE.testing_mode:
-        cg.add_build_flag("-DESPHOME_TESTING_MODE")
-        add_extra_script(
-            "pre",
-            "iram_fix.py",
-            Path(__file__).parent / "iram_fix.py.script",
-        )
-
     if conf[CONF_TYPE] == FRAMEWORK_ESP_IDF:
-        cg.add_platformio_option("framework", "espidf")
         cg.add_build_flag("-DUSE_ESP_IDF")
         cg.add_build_flag("-DUSE_ESP32_FRAMEWORK_ESP_IDF")
+        if use_platformio:
+            cg.add_platformio_option("framework", "espidf")
     else:
-        cg.add_platformio_option("framework", "arduino, espidf")
         cg.add_build_flag("-DUSE_ARDUINO")
         cg.add_build_flag("-DUSE_ESP32_FRAMEWORK_ARDUINO")
+        if use_platformio:
+            cg.add_platformio_option("framework", "arduino, espidf")
+
+            # Add IDF framework source for Arduino builds to ensure it uses the same version as
+            # the ESP-IDF framework
+            if (idf_ver := ARDUINO_IDF_VERSION_LOOKUP.get(framework_ver)) is not None:
+                cg.add_platformio_option(
+                    "platform_packages",
+                    [_format_framework_espidf_version(idf_ver, None)],
+                )
+
+            # ESP32-S2 Arduino: Disable USB Serial on boot to avoid TinyUSB dependency
+            if get_esp32_variant() == VARIANT_ESP32S2:
+                cg.add_build_unflag("-DARDUINO_USB_CDC_ON_BOOT=1")
+                cg.add_build_unflag("-DARDUINO_USB_CDC_ON_BOOT=0")
+                cg.add_build_flag("-DARDUINO_USB_CDC_ON_BOOT=0")
+
         cg.add_define(
             "USE_ARDUINO_VERSION_CODE",
             cg.RawExpression(
                 f"VERSION_CODE({framework_ver.major}, {framework_ver.minor}, {framework_ver.patch})"
             ),
         )
+
         add_idf_sdkconfig_option("CONFIG_MBEDTLS_PSK_MODES", True)
         add_idf_sdkconfig_option("CONFIG_MBEDTLS_CERTIFICATE_BUNDLE", True)
 
-        # Add IDF framework source for Arduino builds to ensure it uses the same version as
-        # the ESP-IDF framework
-        if (idf_ver := ARDUINO_IDF_VERSION_LOOKUP.get(framework_ver)) is not None:
-            cg.add_platformio_option(
-                "platform_packages", [_format_framework_espidf_version(idf_ver, None)]
-            )
-
-        # ESP32-S2 Arduino: Disable USB Serial on boot to avoid TinyUSB dependency
-        if get_esp32_variant() == VARIANT_ESP32S2:
-            cg.add_build_unflag("-DARDUINO_USB_CDC_ON_BOOT=1")
-            cg.add_build_unflag("-DARDUINO_USB_CDC_ON_BOOT=0")
-            cg.add_build_flag("-DARDUINO_USB_CDC_ON_BOOT=0")
-
     cg.add_build_flag("-Wno-nonnull-compare")
 
     add_idf_sdkconfig_option(f"CONFIG_IDF_TARGET_{variant}", True)
@@ -1196,7 +1211,8 @@ async def to_code(config):
             "CONFIG_VFS_SUPPORT_DIR", not advanced[CONF_DISABLE_VFS_SUPPORT_DIR]
         )
 
-    cg.add_platformio_option("board_build.partitions", "partitions.csv")
+    if use_platformio:
+        cg.add_platformio_option("board_build.partitions", "partitions.csv")
     if CONF_PARTITIONS in config:
         add_extra_build_file(
             "partitions.csv", CORE.relative_config_path(config[CONF_PARTITIONS])
@@ -1361,19 +1377,16 @@ def copy_files():
     _write_idf_component_yml()
 
     if "partitions.csv" not in CORE.data[KEY_ESP32][KEY_EXTRA_BUILD_FILES]:
+        flash_size = CORE.data[KEY_ESP32][KEY_FLASH_SIZE]
         if CORE.using_arduino:
             write_file_if_changed(
                 CORE.relative_build_path("partitions.csv"),
-                get_arduino_partition_csv(
-                    CORE.platformio_options.get("board_upload.flash_size")
-                ),
+                get_arduino_partition_csv(flash_size),
             )
         else:
             write_file_if_changed(
                 CORE.relative_build_path("partitions.csv"),
-                get_idf_partition_csv(
-                    CORE.platformio_options.get("board_upload.flash_size")
-                ),
+                get_idf_partition_csv(flash_size),
             )
     # IDF build scripts look for version string to put in the build.
     # However, if the build path does not have an initialized git repo,

esphome/components/esp32/const.py

@@ -2,6 +2,7 @@ import esphome.codegen as cg
 
 KEY_ESP32 = "esp32"
 KEY_BOARD = "board"
+KEY_FLASH_SIZE = "flash_size"
 KEY_VARIANT = "variant"
 KEY_SDKCONFIG_OPTIONS = "sdkconfig_options"
 KEY_COMPONENTS = "components"

esphome/components/esp32/preferences.cpp

@@ -181,7 +181,8 @@ class ESP32Preferences : public ESPPreferences {
     if (actual_len != to_save.len) {
       return true;
     }
-    auto stored_data = std::make_unique<uint8_t[]>(actual_len);
+    // Most preferences are small, use stack buffer with heap fallback for large ones
+    SmallBufferWithHeapFallback<256> stored_data(actual_len);
     err = nvs_get_blob(nvs_handle, key_str, stored_data.get(), &actual_len);
     if (err != 0) {
       ESP_LOGV(TAG, "nvs_get_blob('%s') failed: %s", key_str, esp_err_to_name(err));

esphome/components/esp32_ble/ble_uuid.h

@@ -46,6 +46,8 @@ class ESPBTUUID {
 
   esp_bt_uuid_t get_uuid() const;
 
+  // Remove before 2026.8.0
+  ESPDEPRECATED("Use to_str() instead. Removed in 2026.8.0", "2026.2.0")
   std::string to_string() const;
   const char *to_str(std::span<char, UUID_STR_LEN> output) const;
 

esphome/components/esp32_ble_client/ble_client_base.cpp

@@ -50,7 +50,7 @@ void BLEClientBase::loop() {
     this->set_state(espbt::ClientState::INIT);
     return;
   }
-  if (this->state_ == espbt::ClientState::INIT) {
+  if (this->state() == espbt::ClientState::INIT) {
     auto ret = esp_ble_gattc_app_register(this->app_id);
     if (ret) {
       ESP_LOGE(TAG, "gattc app register failed. app_id=%d code=%d", this->app_id, ret);
@@ -60,7 +60,7 @@ void BLEClientBase::loop() {
   }
   // If idle, we can disable the loop as connect()
   // will enable it again when a connection is needed.
-  else if (this->state_ == espbt::ClientState::IDLE) {
+  else if (this->state() == espbt::ClientState::IDLE) {
     this->disable_loop();
   }
 }
@@ -86,7 +86,7 @@ bool BLEClientBase::parse_device(const espbt::ESPBTDevice &device) {
     return false;
   if (this->address_ == 0 || device.address_uint64() != this->address_)
     return false;
-  if (this->state_ != espbt::ClientState::IDLE)
+  if (this->state() != espbt::ClientState::IDLE)
     return false;
 
   this->log_event_("Found device");
@@ -102,10 +102,10 @@ bool BLEClientBase::parse_device(const espbt::ESPBTDevice &device) {
 
 void BLEClientBase::connect() {
   // Prevent duplicate connection attempts
-  if (this->state_ == espbt::ClientState::CONNECTING || this->state_ == espbt::ClientState::CONNECTED ||
-      this->state_ == espbt::ClientState::ESTABLISHED) {
+  if (this->state() == espbt::ClientState::CONNECTING || this->state() == espbt::ClientState::CONNECTED ||
+      this->state() == espbt::ClientState::ESTABLISHED) {
     ESP_LOGW(TAG, "[%d] [%s] Connection already in progress, state=%s", this->connection_index_, this->address_str_,
-             espbt::client_state_to_string(this->state_));
+             espbt::client_state_to_string(this->state()));
     return;
   }
   ESP_LOGI(TAG, "[%d] [%s] 0x%02x Connecting", this->connection_index_, this->address_str_, this->remote_addr_type_);
@@ -133,12 +133,12 @@ void BLEClientBase::connect() {
 esp_err_t BLEClientBase::pair() { return esp_ble_set_encryption(this->remote_bda_, ESP_BLE_SEC_ENCRYPT); }
 
 void BLEClientBase::disconnect() {
-  if (this->state_ == espbt::ClientState::IDLE || this->state_ == espbt::ClientState::DISCONNECTING) {
+  if (this->state() == espbt::ClientState::IDLE || this->state() == espbt::ClientState::DISCONNECTING) {
     ESP_LOGI(TAG, "[%d] [%s] Disconnect requested, but already %s", this->connection_index_, this->address_str_,
-             espbt::client_state_to_string(this->state_));
+             espbt::client_state_to_string(this->state()));
     return;
   }
-  if (this->state_ == espbt::ClientState::CONNECTING || this->conn_id_ == UNSET_CONN_ID) {
+  if (this->state() == espbt::ClientState::CONNECTING || this->conn_id_ == UNSET_CONN_ID) {
     ESP_LOGD(TAG, "[%d] [%s] Disconnect before connected, disconnect scheduled", this->connection_index_,
              this->address_str_);
     this->want_disconnect_ = true;
@@ -150,7 +150,7 @@ void BLEClientBase::disconnect() {
 void BLEClientBase::unconditional_disconnect() {
   // Disconnect without checking the state.
   ESP_LOGI(TAG, "[%d] [%s] Disconnecting (conn_id: %d).", this->connection_index_, this->address_str_, this->conn_id_);
-  if (this->state_ == espbt::ClientState::DISCONNECTING) {
+  if (this->state() == espbt::ClientState::DISCONNECTING) {
     this->log_error_("Already disconnecting");
     return;
   }
@@ -170,7 +170,7 @@ void BLEClientBase::unconditional_disconnect() {
     this->log_gattc_warning_("esp_ble_gattc_close", err);
   }
 
-  if (this->state_ == espbt::ClientState::DISCOVERED) {
+  if (this->state() == espbt::ClientState::DISCOVERED) {
     this->set_address(0);
     this->set_state(espbt::ClientState::IDLE);
   } else {
@@ -295,18 +295,18 @@ bool BLEClientBase::gattc_event_handler(esp_gattc_cb_event_t event, esp_gatt_if_
       // ESP-IDF's BLE stack may send ESP_GATTC_OPEN_EVT after esp_ble_gattc_open() returns an
       // error, if the error occurred at the BTA/GATT layer. This can result in the event
       // arriving after we've already transitioned to IDLE state.
-      if (this->state_ == espbt::ClientState::IDLE) {
+      if (this->state() == espbt::ClientState::IDLE) {
         ESP_LOGD(TAG, "[%d] [%s] ESP_GATTC_OPEN_EVT in IDLE state (status=%d), ignoring", this->connection_index_,
                  this->address_str_, param->open.status);
         break;
       }
 
-      if (this->state_ != espbt::ClientState::CONNECTING) {
+      if (this->state() != espbt::ClientState::CONNECTING) {
         // This should not happen but lets log it in case it does
         // because it means we have a bad assumption about how the
         // ESP BT stack works.
         ESP_LOGE(TAG, "[%d] [%s] ESP_GATTC_OPEN_EVT in %s state (status=%d)", this->connection_index_,
-                 this->address_str_, espbt::client_state_to_string(this->state_), param->open.status);
+                 this->address_str_, espbt::client_state_to_string(this->state()), param->open.status);
       }
       if (param->open.status != ESP_GATT_OK && param->open.status != ESP_GATT_ALREADY_OPEN) {
         this->log_gattc_warning_("Connection open", param->open.status);
@@ -327,7 +327,7 @@ bool BLEClientBase::gattc_event_handler(esp_gattc_cb_event_t event, esp_gatt_if_
       if (this->connection_type_ == espbt::ConnectionType::V3_WITH_CACHE) {
         // Cached connections already connected with medium parameters, no update needed
         // only set our state, subclients might have more stuff to do yet.
-        this->state_ = espbt::ClientState::ESTABLISHED;
+        this->set_state_internal_(espbt::ClientState::ESTABLISHED);
         break;
       }
       // For V3_WITHOUT_CACHE, we already set fast params before connecting
@@ -356,7 +356,7 @@ bool BLEClientBase::gattc_event_handler(esp_gattc_cb_event_t event, esp_gatt_if_
         return false;
       // Check if we were disconnected while waiting for service discovery
       if (param->disconnect.reason == ESP_GATT_CONN_TERMINATE_PEER_USER &&
-          this->state_ == espbt::ClientState::CONNECTED) {
+          this->state() == espbt::ClientState::CONNECTED) {
         this->log_warning_("Remote closed during discovery");
       } else {
         ESP_LOGD(TAG, "[%d] [%s] ESP_GATTC_DISCONNECT_EVT, reason 0x%02x", this->connection_index_, this->address_str_,
@@ -433,7 +433,7 @@ bool BLEClientBase::gattc_event_handler(esp_gattc_cb_event_t event, esp_gatt_if_
 #endif
       }
       ESP_LOGI(TAG, "[%d] [%s] Service discovery complete", this->connection_index_, this->address_str_);
-      this->state_ = espbt::ClientState::ESTABLISHED;
+      this->set_state_internal_(espbt::ClientState::ESTABLISHED);
       break;
     }
     case ESP_GATTC_READ_DESCR_EVT: {

esphome/components/esp32_ble_client/ble_client_base.h

@@ -44,7 +44,7 @@ class BLEClientBase : public espbt::ESPBTClient, public Component {
   void unconditional_disconnect();
   void release_services();
 
-  bool connected() { return this->state_ == espbt::ClientState::ESTABLISHED; }
+  bool connected() { return this->state() == espbt::ClientState::ESTABLISHED; }
 
   void set_auto_connect(bool auto_connect) { this->auto_connect_ = auto_connect; }
 

esphome/components/esp32_ble_tracker/esp32_ble_tracker.cpp

@@ -105,15 +105,13 @@ void ESP32BLETracker::loop() {
   }
 
   // Check for scan timeout - moved here from scheduler to avoid false reboots
-  // when the loop is blocked
+  // when the loop is blocked. This must run every iteration for safety.
   if (this->scanner_state_ == ScannerState::RUNNING) {
     switch (this->scan_timeout_state_) {
       case ScanTimeoutState::MONITORING: {
-        uint32_t now = App.get_loop_component_start_time();
-        uint32_t timeout_ms = this->scan_duration_ * 2000;
         // Robust time comparison that handles rollover correctly
         // This works because unsigned arithmetic wraps around predictably
-        if ((now - this->scan_start_time_) > timeout_ms) {
+        if ((App.get_loop_component_start_time() - this->scan_start_time_) > this->scan_timeout_ms_) {
           // First time we've seen the timeout exceeded - wait one more loop iteration
           // This ensures all components have had a chance to process pending events
           // This is because esp32_ble may not have run yet and called
@@ -128,13 +126,31 @@ void ESP32BLETracker::loop() {
         ESP_LOGE(TAG, "Scan never terminated, rebooting");
         App.reboot();
         break;
-
       case ScanTimeoutState::INACTIVE:
-        // This case should be unreachable - scanner and timeout states are always synchronized
         break;
     }
   }
 
+  // Fast path: skip expensive client state counting and processing
+  // if no state has changed since last loop iteration.
+  //
+  // How state changes ensure we reach the code below:
+  // - handle_scanner_failure_(): scanner_state_ becomes FAILED via set_scanner_state_(), or
+  //   scan_set_param_failed_ requires scanner_state_==RUNNING which can only be reached via
+  //   set_scanner_state_(RUNNING) in gap_scan_start_complete_() (scan params are set during
+  //   STARTING, not RUNNING, so version is always incremented before this condition is true)
+  // - start_scan_(): scanner_state_ becomes IDLE via set_scanner_state_() in cleanup_scan_state_()
+  // - try_promote_discovered_clients_(): client enters DISCOVERED via set_state(), or
+  //   connecting client finishes (state change), or scanner reaches RUNNING/IDLE
+  //
+  // All conditions that affect the logic below are tied to state changes that increment
+  // state_version_, so the fast path is safe.
+  if (this->state_version_ == this->last_processed_version_) {
+    return;
+  }
+  this->last_processed_version_ = this->state_version_;
+
+  // State changed - do full processing
   ClientStateCounts counts = this->count_client_states_();
   if (counts != this->client_state_counts_) {
     this->client_state_counts_ = counts;
@@ -142,6 +158,7 @@ void ESP32BLETracker::loop() {
              this->client_state_counts_.discovered, this->client_state_counts_.disconnecting);
   }
 
+  // Scanner failure: reached when set_scanner_state_(FAILED) or scan_set_param_failed_ set
   if (this->scanner_state_ == ScannerState::FAILED ||
       (this->scan_set_param_failed_ && this->scanner_state_ == ScannerState::RUNNING)) {
     this->handle_scanner_failure_();
@@ -160,6 +177,8 @@ void ESP32BLETracker::loop() {
 
   */
 
+  // Start scan: reached when scanner_state_ becomes IDLE (via set_scanner_state_()) and
+  // all clients are idle (their state changes increment version when they finish)
   if (this->scanner_state_ == ScannerState::IDLE && !counts.connecting && !counts.disconnecting && !counts.discovered) {
 #ifdef USE_ESP32_BLE_SOFTWARE_COEXISTENCE
     this->update_coex_preference_(false);
@@ -168,8 +187,9 @@ void ESP32BLETracker::loop() {
       this->start_scan_(false);  // first = false
     }
   }
-  // If there is a discovered client and no connecting
-  // clients, then promote the discovered client to ready to connect.
+  // Promote discovered clients: reached when a client's state becomes DISCOVERED (via set_state()),
+  // or when a blocking condition clears (connecting client finishes, scanner reaches RUNNING/IDLE).
+  // All these trigger state_version_ increment, so we'll process and check promotion eligibility.
   // We check both RUNNING and IDLE states because:
   // - RUNNING: gap_scan_event_handler initiates stop_scan_() but promotion can happen immediately
   // - IDLE: Scanner has already stopped (naturally or by gap_scan_event_handler)
@@ -236,6 +256,7 @@ void ESP32BLETracker::start_scan_(bool first) {
   // Start timeout monitoring in loop() instead of using scheduler
   // This prevents false reboots when the loop is blocked
   this->scan_start_time_ = App.get_loop_component_start_time();
+  this->scan_timeout_ms_ = this->scan_duration_ * 2000;
   this->scan_timeout_state_ = ScanTimeoutState::MONITORING;
 
   esp_err_t err = esp_ble_gap_set_scan_params(&this->scan_params_);
@@ -253,6 +274,10 @@ void ESP32BLETracker::start_scan_(bool first) {
 void ESP32BLETracker::register_client(ESPBTClient *client) {
 #ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
   client->app_id = ++this->app_id_;
+  // Give client a pointer to our state_version_ so it can notify us of state changes.
+  // This enables loop() fast-path optimization - we skip expensive work when no state changed.
+  // Safe because ESP32BLETracker (singleton) outlives all registered clients.
+  client->set_tracker_state_version(&this->state_version_);
   this->clients_.push_back(client);
   this->recalculate_advertisement_parser_types();
 #endif
@@ -382,6 +407,7 @@ void ESP32BLETracker::gattc_event_handler(esp_gattc_cb_event_t event, esp_gatt_i
 
 void ESP32BLETracker::set_scanner_state_(ScannerState state) {
   this->scanner_state_ = state;
+  this->state_version_++;
   for (auto *listener : this->scanner_state_listeners_) {
     listener->on_scanner_state(state);
   }

esphome/components/esp32_ble_tracker/esp32_ble_tracker.h

@@ -216,6 +216,19 @@ enum class ConnectionType : uint8_t {
   V3_WITHOUT_CACHE
 };
 
+/// Base class for BLE GATT clients that connect to remote devices.
+///
+/// State Change Tracking Design:
+/// -----------------------------
+/// ESP32BLETracker::loop() needs to know when client states change to avoid
+/// expensive polling. Rather than checking all clients every iteration (~7000/min),
+/// we use a version counter owned by ESP32BLETracker that clients increment on
+/// state changes. The tracker compares versions to skip work when nothing changed.
+///
+/// Ownership: ESP32BLETracker owns state_version_. Clients hold a non-owning
+/// pointer (tracker_state_version_) set during register_client(). Clients
+/// increment the counter through this pointer when their state changes.
+/// The pointer may be null if the client is not registered with a tracker.
 class ESPBTClient : public ESPBTDeviceListener {
  public:
   virtual bool gattc_event_handler(esp_gattc_cb_event_t event, esp_gatt_if_t gattc_if,
@@ -225,26 +238,49 @@ class ESPBTClient : public ESPBTDeviceListener {
   virtual void disconnect() = 0;
   bool disconnect_pending() const { return this->want_disconnect_; }
   void cancel_pending_disconnect() { this->want_disconnect_ = false; }
+
+  /// Set the client state with IDLE handling (clears want_disconnect_).
+  /// Notifies the tracker of state change for loop optimization.
   virtual void set_state(ClientState st) {
-    this->state_ = st;
+    this->set_state_internal_(st);
     if (st == ClientState::IDLE) {
       this->want_disconnect_ = false;
     }
   }
-  ClientState state() const { return state_; }
+  ClientState state() const { return this->state_; }
+
+  /// Called by ESP32BLETracker::register_client() to enable state change notifications.
+  /// The pointer must remain valid for the lifetime of the client (guaranteed since
+  /// ESP32BLETracker is a singleton that outlives all clients).
+  void set_tracker_state_version(uint8_t *version) { this->tracker_state_version_ = version; }
 
   // Memory optimized layout
   uint8_t app_id;  // App IDs are small integers assigned sequentially
 
  protected:
-  // Group 1: 1-byte types
-  ClientState state_{ClientState::INIT};
+  /// Set state without IDLE handling - use for direct state transitions.
+  /// Increments the tracker's state version counter to signal that loop()
+  /// should do full processing on the next iteration.
+  void set_state_internal_(ClientState st) {
+    this->state_ = st;
+    // Notify tracker that state changed (tracker_state_version_ is owned by ESP32BLETracker)
+    if (this->tracker_state_version_ != nullptr) {
+      (*this->tracker_state_version_)++;
+    }
+  }
+
   // want_disconnect_ is set to true when a disconnect is requested
   // while the client is connecting. This is used to disconnect the
   // client as soon as we get the connection id (conn_id_) from the
   // ESP_GATTC_OPEN_EVT event.
   bool want_disconnect_{false};
-  // 2 bytes used, 2 bytes padding
+
+ private:
+  ClientState state_{ClientState::INIT};
+  /// Non-owning pointer to ESP32BLETracker::state_version_. When this client's
+  /// state changes, we increment the tracker's counter to signal that loop()
+  /// should perform full processing. Null if client not registered with tracker.
+  uint8_t *tracker_state_version_{nullptr};
 };
 
 class ESP32BLETracker : public Component,
@@ -380,6 +416,16 @@ class ESP32BLETracker : public Component,
   // Group 4: 1-byte types (enums, uint8_t, bool)
   uint8_t app_id_{0};
   uint8_t scan_start_fail_count_{0};
+  /// Version counter for loop() fast-path optimization. Incremented when:
+  /// - Scanner state changes (via set_scanner_state_())
+  /// - Any registered client's state changes (clients hold pointer to this counter)
+  /// Owned by this class; clients receive non-owning pointer via register_client().
+  /// When loop() sees state_version_ == last_processed_version_, it skips expensive
+  /// client state counting and takes the fast path (just timeout check + return).
+  uint8_t state_version_{0};
+  /// Last state_version_ value when loop() did full processing. Compared against
+  /// state_version_ to detect if any state changed since last iteration.
+  uint8_t last_processed_version_{0};
   ScannerState scanner_state_{ScannerState::IDLE};
   bool scan_continuous_;
   bool scan_active_;
@@ -396,6 +442,8 @@ class ESP32BLETracker : public Component,
     EXCEEDED_WAIT,  // Timeout exceeded, waiting one loop before reboot
   };
   uint32_t scan_start_time_{0};
+  /// Precomputed timeout value: scan_duration_ * 2000
+  uint32_t scan_timeout_ms_{0};
   ScanTimeoutState scan_timeout_state_{ScanTimeoutState::INACTIVE};
 };
 

esphome/components/esp32_hosted/update/esp32_hosted_update.cpp

@@ -69,7 +69,10 @@ void Esp32HostedUpdate::setup() {
   // Get coprocessor version
   esp_hosted_coprocessor_fwver_t ver_info;
   if (esp_hosted_get_coprocessor_fwversion(&ver_info) == ESP_OK) {
-    this->update_info_.current_version = str_sprintf("%d.%d.%d", ver_info.major1, ver_info.minor1, ver_info.patch1);
+    // 16 bytes: "255.255.255" (11 chars) + null + safety margin
+    char buf[16];
+    snprintf(buf, sizeof(buf), "%d.%d.%d", ver_info.major1, ver_info.minor1, ver_info.patch1);
+    this->update_info_.current_version = buf;
   } else {
     this->update_info_.current_version = "unknown";
   }

esphome/components/esp8266/core.cpp

@@ -6,7 +6,11 @@
 #include "esphome/core/helpers.h"
 #include "preferences.h"
 #include <Arduino.h>
-#include <Esp.h>
+#include <core_esp8266_features.h>
+
+extern "C" {
+#include <user_interface.h>
+}
 
 namespace esphome {
 
@@ -16,23 +20,19 @@ void IRAM_ATTR HOT delay(uint32_t ms) { ::delay(ms); }
 uint32_t IRAM_ATTR HOT micros() { return ::micros(); }
 void IRAM_ATTR HOT delayMicroseconds(uint32_t us) { delay_microseconds_safe(us); }
 void arch_restart() {
-  ESP.restart();  // NOLINT(readability-static-accessed-through-instance)
+  system_restart();
   // restart() doesn't always end execution
   while (true) {  // NOLINT(clang-diagnostic-unreachable-code)
     yield();
   }
 }
 void arch_init() {}
-void IRAM_ATTR HOT arch_feed_wdt() {
-  ESP.wdtFeed();  // NOLINT(readability-static-accessed-through-instance)
-}
+void IRAM_ATTR HOT arch_feed_wdt() { system_soft_wdt_feed(); }
 
 uint8_t progmem_read_byte(const uint8_t *addr) {
   return pgm_read_byte(addr);  // NOLINT
 }
-uint32_t IRAM_ATTR HOT arch_get_cpu_cycle_count() {
-  return ESP.getCycleCount();  // NOLINT(readability-static-accessed-through-instance)
-}
+uint32_t IRAM_ATTR HOT arch_get_cpu_cycle_count() { return esp_get_cycle_count(); }
 uint32_t arch_get_cpu_freq_hz() { return F_CPU; }
 
 void force_link_symbols() {

esphome/components/esp8266/gpio.cpp

@@ -99,7 +99,7 @@ void ESP8266GPIOPin::pin_mode(gpio::Flags flags) {
 }
 
 size_t ESP8266GPIOPin::dump_summary(char *buffer, size_t len) const {
-  return snprintf(buffer, len, "GPIO%u", this->pin_);
+  return buf_append_printf(buffer, len, 0, "GPIO%u", this->pin_);
 }
 
 bool ESP8266GPIOPin::digital_read() {

esphome/components/event/__init__.py

@@ -90,9 +90,7 @@ async def setup_event_core_(var, config, *, event_types: list[str]):
 
     for conf in config.get(CONF_ON_EVENT, []):
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(
-            trigger, [(cg.std_string, "event_type")], conf
-        )
+        await automation.build_automation(trigger, [(cg.StringRef, "event_type")], conf)
 
     cg.add(var.set_event_types(event_types))
 

esphome/components/event/automation.h

@@ -14,10 +14,10 @@ template<typename... Ts> class TriggerEventAction : public Action<Ts...>, public
   void play(const Ts &...x) override { this->parent_->trigger(this->event_type_.value(x...)); }
 };
 
-class EventTrigger : public Trigger<std::string> {
+class EventTrigger : public Trigger<StringRef> {
  public:
   EventTrigger(Event *event) {
-    event->add_on_event_callback([this](const std::string &event_type) { this->trigger(event_type); });
+    event->add_on_event_callback([this](StringRef event_type) { this->trigger(event_type); });
   }
 };
 

esphome/components/event/event.cpp

@@ -23,7 +23,7 @@ void Event::trigger(const std::string &event_type) {
   }
   this->last_event_type_ = found;
   ESP_LOGD(TAG, "'%s' >> '%s'", this->get_name().c_str(), this->last_event_type_);
-  this->event_callback_.call(event_type);
+  this->event_callback_.call(StringRef(found));
 #if defined(USE_EVENT) && defined(USE_CONTROLLER_REGISTRY)
   ControllerRegistry::notify_event(this);
 #endif
@@ -45,7 +45,7 @@ void Event::set_event_types(const std::vector<const char *> &event_types) {
   this->last_event_type_ = nullptr;  // Reset when types change
 }
 
-void Event::add_on_event_callback(std::function<void(const std::string &event_type)> &&callback) {
+void Event::add_on_event_callback(std::function<void(StringRef event_type)> &&callback) {
   this->event_callback_.add(std::move(callback));
 }
 

esphome/components/event/event.h

@@ -70,10 +70,10 @@ class Event : public EntityBase, public EntityBase_DeviceClass {
   /// Check if an event has been triggered.
   bool has_event() const { return this->last_event_type_ != nullptr; }
 
-  void add_on_event_callback(std::function<void(const std::string &event_type)> &&callback);
+  void add_on_event_callback(std::function<void(StringRef event_type)> &&callback);
 
  protected:
-  LazyCallbackManager<void(const std::string &event_type)> event_callback_;
+  LazyCallbackManager<void(StringRef event_type)> event_callback_;
   FixedVector<const char *> types_;
 
  private:

esphome/components/ezo/ezo.cpp

@@ -160,7 +160,7 @@ void EZOSensor::loop() {
   this->commands_.pop_front();
 }
 
-void EZOSensor::add_command_(const std::string &command, EzoCommandType command_type, uint16_t delay_ms) {
+void EZOSensor::add_command_(const char *command, EzoCommandType command_type, uint16_t delay_ms) {
   std::unique_ptr<EzoCommand> ezo_command(new EzoCommand);
   ezo_command->command = command;
   ezo_command->command_type = command_type;
@@ -169,13 +169,17 @@ void EZOSensor::add_command_(const std::string &command, EzoCommandType command_
 }
 
 void EZOSensor::set_calibration_point_(EzoCalibrationType type, float value) {
-  std::string payload = str_sprintf("Cal,%s,%0.2f", EZO_CALIBRATION_TYPE_STRINGS[type], value);
+  // max 21: "Cal,"(4) + type(4) + ","(1) + float(11) + null; use 24 for safety
+  char payload[24];
+  snprintf(payload, sizeof(payload), "Cal,%s,%0.2f", EZO_CALIBRATION_TYPE_STRINGS[type], value);
   this->add_command_(payload, EzoCommandType::EZO_CALIBRATION, 900);
 }
 
 void EZOSensor::set_address(uint8_t address) {
   if (address > 0 && address < 128) {
-    std::string payload = str_sprintf("I2C,%u", address);
+    // max 8: "I2C,"(4) + uint8(3) + null
+    char payload[8];
+    snprintf(payload, sizeof(payload), "I2C,%u", address);
     this->new_address_ = address;
     this->add_command_(payload, EzoCommandType::EZO_I2C);
   } else {
@@ -194,7 +198,9 @@ void EZOSensor::get_slope() { this->add_command_("Slope,?", EzoCommandType::EZO_
 void EZOSensor::get_t() { this->add_command_("T,?", EzoCommandType::EZO_T); }
 
 void EZOSensor::set_t(float value) {
-  std::string payload = str_sprintf("T,%0.2f", value);
+  // max 14 bytes: "T,"(2) + float with "%0.2f" (up to 11 chars) + null(1); use 16 for alignment
+  char payload[16];
+  snprintf(payload, sizeof(payload), "T,%0.2f", value);
   this->add_command_(payload, EzoCommandType::EZO_T);
 }
 
@@ -215,7 +221,9 @@ void EZOSensor::set_calibration_point_high(float value) {
 }
 
 void EZOSensor::set_calibration_generic(float value) {
-  std::string payload = str_sprintf("Cal,%0.2f", value);
+  // exact 16 bytes: "Cal," (4) + float with "%0.2f" (up to 11 chars, e.g. "-9999999.99") + null (1) = 16
+  char payload[16];
+  snprintf(payload, sizeof(payload), "Cal,%0.2f", value);
   this->add_command_(payload, EzoCommandType::EZO_CALIBRATION, 900);
 }
 
@@ -223,13 +231,11 @@ void EZOSensor::clear_calibration() { this->add_command_("Cal,clear", EzoCommand
 
 void EZOSensor::get_led_state() { this->add_command_("L,?", EzoCommandType::EZO_LED); }
 
-void EZOSensor::set_led_state(bool on) {
-  std::string to_send = "L,";
-  to_send += on ? "1" : "0";
-  this->add_command_(to_send, EzoCommandType::EZO_LED);
-}
+void EZOSensor::set_led_state(bool on) { this->add_command_(on ? "L,1" : "L,0", EzoCommandType::EZO_LED); }
 
-void EZOSensor::send_custom(const std::string &to_send) { this->add_command_(to_send, EzoCommandType::EZO_CUSTOM); }
+void EZOSensor::send_custom(const std::string &to_send) {
+  this->add_command_(to_send.c_str(), EzoCommandType::EZO_CUSTOM);
+}
 
 }  // namespace ezo
 }  // namespace esphome

esphome/components/ezo/ezo.h

@@ -92,7 +92,7 @@ class EZOSensor : public sensor::Sensor, public PollingComponent, public i2c::I2
   std::deque<std::unique_ptr<EzoCommand>> commands_;
   int new_address_;
 
-  void add_command_(const std::string &command, EzoCommandType command_type, uint16_t delay_ms = 300);
+  void add_command_(const char *command, EzoCommandType command_type, uint16_t delay_ms = 300);
 
   void set_calibration_point_(EzoCalibrationType type, float value);
 

esphome/components/ezo_pmp/ezo_pmp.cpp

@@ -318,90 +318,93 @@ void EzoPMP::send_next_command_() {
   switch (this->next_command_) {
     // Read Commands
     case EZO_PMP_COMMAND_READ_DOSING:  // Page 54
-      command_buffer_length = sprintf((char *) command_buffer, "D,?");
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "D,?");
       break;
 
     case EZO_PMP_COMMAND_READ_SINGLE_REPORT:  // Single Report (page 53)
-      command_buffer_length = sprintf((char *) command_buffer, "R");
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "R");
       break;
 
     case EZO_PMP_COMMAND_READ_MAX_FLOW_RATE:
-      command_buffer_length = sprintf((char *) command_buffer, "DC,?");
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "DC,?");
       break;
 
     case EZO_PMP_COMMAND_READ_PAUSE_STATUS:
-      command_buffer_length = sprintf((char *) command_buffer, "P,?");
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "P,?");
       break;
 
     case EZO_PMP_COMMAND_READ_TOTAL_VOLUME_DOSED:
-      command_buffer_length = sprintf((char *) command_buffer, "TV,?");
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "TV,?");
       break;
 
     case EZO_PMP_COMMAND_READ_ABSOLUTE_TOTAL_VOLUME_DOSED:
-      command_buffer_length = sprintf((char *) command_buffer, "ATV,?");
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "ATV,?");
       break;
 
     case EZO_PMP_COMMAND_READ_CALIBRATION_STATUS:
-      command_buffer_length = sprintf((char *) command_buffer, "Cal,?");
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "Cal,?");
       break;
 
     case EZO_PMP_COMMAND_READ_PUMP_VOLTAGE:
-      command_buffer_length = sprintf((char *) command_buffer, "PV,?");
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "PV,?");
       break;
 
       // Non-Read Commands
 
     case EZO_PMP_COMMAND_FIND:  // Find (page 52)
-      command_buffer_length = sprintf((char *) command_buffer, "Find");
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "Find");
       wait_time_for_command = 60000;  // This command will block all updates for a minute
       break;
 
     case EZO_PMP_COMMAND_DOSE_CONTINUOUSLY:  // Continuous Dispensing (page 54)
-      command_buffer_length = sprintf((char *) command_buffer, "D,*");
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "D,*");
       break;
 
     case EZO_PMP_COMMAND_CLEAR_TOTAL_VOLUME_DOSED:  // Clear Total Volume Dosed (page 64)
-      command_buffer_length = sprintf((char *) command_buffer, "Clear");
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "Clear");
       break;
 
     case EZO_PMP_COMMAND_CLEAR_CALIBRATION:  // Clear Calibration (page 65)
-      command_buffer_length = sprintf((char *) command_buffer, "Cal,clear");
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "Cal,clear");
       break;
 
     case EZO_PMP_COMMAND_PAUSE_DOSING:  // Pause (page 61)
-      command_buffer_length = sprintf((char *) command_buffer, "P");
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "P");
       break;
 
     case EZO_PMP_COMMAND_STOP_DOSING:  // Stop (page 62)
-      command_buffer_length = sprintf((char *) command_buffer, "X");
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "X");
       break;
 
       // Non-Read commands with parameters
 
     case EZO_PMP_COMMAND_DOSE_VOLUME:  // Volume Dispensing (page 55)
-      command_buffer_length = sprintf((char *) command_buffer, "D,%0.1f", this->next_command_volume_);
+      command_buffer_length =
+          snprintf((char *) command_buffer, sizeof(command_buffer), "D,%0.1f", this->next_command_volume_);
       break;
 
     case EZO_PMP_COMMAND_DOSE_VOLUME_OVER_TIME:  // Dose over time (page 56)
-      command_buffer_length =
-          sprintf((char *) command_buffer, "D,%0.1f,%i", this->next_command_volume_, this->next_command_duration_);
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "D,%0.1f,%i",
+                                       this->next_command_volume_, this->next_command_duration_);
       break;
 
     case EZO_PMP_COMMAND_DOSE_WITH_CONSTANT_FLOW_RATE:  // Constant Flow Rate (page 57)
-      command_buffer_length =
-          sprintf((char *) command_buffer, "DC,%0.1f,%i", this->next_command_volume_, this->next_command_duration_);
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "DC,%0.1f,%i",
+                                       this->next_command_volume_, this->next_command_duration_);
       break;
 
     case EZO_PMP_COMMAND_SET_CALIBRATION_VOLUME:  // Set Calibration Volume (page 65)
-      command_buffer_length = sprintf((char *) command_buffer, "Cal,%0.2f", this->next_command_volume_);
+      command_buffer_length =
+          snprintf((char *) command_buffer, sizeof(command_buffer), "Cal,%0.2f", this->next_command_volume_);
       break;
 
     case EZO_PMP_COMMAND_CHANGE_I2C_ADDRESS:  // Change I2C Address (page 73)
-      command_buffer_length = sprintf((char *) command_buffer, "I2C,%i", this->next_command_duration_);
+      command_buffer_length =
+          snprintf((char *) command_buffer, sizeof(command_buffer), "I2C,%i", this->next_command_duration_);
       break;
 
     case EZO_PMP_COMMAND_EXEC_ARBITRARY_COMMAND_ADDRESS:  // Run an arbitrary command
-      command_buffer_length = sprintf((char *) command_buffer, this->arbitrary_command_, this->next_command_duration_);
+      command_buffer_length = snprintf((char *) command_buffer, sizeof(command_buffer), "%s", this->arbitrary_command_);
       ESP_LOGI(TAG, "Sending arbitrary command: %s", (char *) command_buffer);
       break;
 

esphome/components/fan/__init__.py

@@ -77,7 +77,7 @@ FanSpeedSetTrigger = fan_ns.class_(
     "FanSpeedSetTrigger", automation.Trigger.template(cg.int_)
 )
 FanPresetSetTrigger = fan_ns.class_(
-    "FanPresetSetTrigger", automation.Trigger.template(cg.std_string)
+    "FanPresetSetTrigger", automation.Trigger.template(cg.StringRef)
 )
 
 FanIsOnCondition = fan_ns.class_("FanIsOnCondition", automation.Condition.template())
@@ -287,7 +287,7 @@ async def setup_fan_core_(var, config):
         await automation.build_automation(trigger, [(cg.int_, "x")], conf)
     for conf in config.get(CONF_ON_PRESET_SET, []):
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(trigger, [(cg.std_string, "x")], conf)
+        await automation.build_automation(trigger, [(cg.StringRef, "x")], conf)
 
 
 async def register_fan(var, config):

esphome/components/fan/automation.h

@@ -208,7 +208,7 @@ class FanSpeedSetTrigger : public Trigger<int> {
   int last_speed_;
 };
 
-class FanPresetSetTrigger : public Trigger<std::string> {
+class FanPresetSetTrigger : public Trigger<StringRef> {
  public:
   FanPresetSetTrigger(Fan *state) {
     state->add_on_state_callback([this, state]() {
@@ -216,7 +216,7 @@ class FanPresetSetTrigger : public Trigger<std::string> {
       auto should_trigger = preset_mode != this->last_preset_mode_;
       this->last_preset_mode_ = preset_mode;
       if (should_trigger) {
-        this->trigger(std::string(preset_mode));
+        this->trigger(preset_mode);
       }
     });
     this->last_preset_mode_ = state->get_preset_mode();

esphome/components/gdk101/gdk101.cpp

@@ -163,9 +163,10 @@ bool GDK101Component::read_fw_version_(uint8_t *data) {
       return false;
     }
 
-    const std::string fw_version_str = str_sprintf("%d.%d", data[0], data[1]);
-
-    this->fw_version_text_sensor_->publish_state(fw_version_str);
+    // max 8: "255.255" (7 chars) + null
+    char buf[8];
+    snprintf(buf, sizeof(buf), "%d.%d", data[0], data[1]);
+    this->fw_version_text_sensor_->publish_state(buf);
   }
 #endif  // USE_TEXT_SENSOR
   return true;

esphome/components/homeassistant/number/homeassistant_number.cpp

@@ -97,7 +97,7 @@ void HomeassistantNumber::control(float value) {
   entity_value.key = VALUE_KEY;
   // Stack buffer - no heap allocation; %g produces shortest representation
   char value_buf[16];
-  snprintf(value_buf, sizeof(value_buf), "%g", value);
+  buf_append_printf(value_buf, sizeof(value_buf), 0, "%g", value);
   entity_value.value = StringRef(value_buf);
 
   api::global_api_server->send_homeassistant_action(resp);

esphome/components/infrared/infrared.cpp

@@ -18,7 +18,15 @@ InfraredCall &InfraredCall::set_carrier_frequency(uint32_t frequency) {
 
 InfraredCall &InfraredCall::set_raw_timings(const std::vector<int32_t> &timings) {
   this->raw_timings_ = &timings;
-  this->packed_data_ = nullptr;  // Clear packed if vector is set
+  this->packed_data_ = nullptr;
+  this->base64url_ptr_ = nullptr;
+  return *this;
+}
+
+InfraredCall &InfraredCall::set_raw_timings_base64url(const std::string &base64url) {
+  this->base64url_ptr_ = &base64url;
+  this->raw_timings_ = nullptr;
+  this->packed_data_ = nullptr;
   return *this;
 }
 
@@ -26,7 +34,8 @@ InfraredCall &InfraredCall::set_raw_timings_packed(const uint8_t *data, uint16_t
   this->packed_data_ = data;
   this->packed_length_ = length;
   this->packed_count_ = count;
-  this->raw_timings_ = nullptr;  // Clear vector if packed is set
+  this->raw_timings_ = nullptr;
+  this->base64url_ptr_ = nullptr;
   return *this;
 }
 
@@ -92,6 +101,23 @@ void Infrared::control(const InfraredCall &call) {
                                                call.get_packed_count());
     ESP_LOGD(TAG, "Transmitting packed raw timings: count=%u, repeat=%u", call.get_packed_count(),
              call.get_repeat_count());
+  } else if (call.is_base64url()) {
+    // Decode base64url (URL-safe) into transmit buffer
+    if (!transmit_data->set_data_from_base64url(call.get_base64url_data())) {
+      ESP_LOGE(TAG, "Invalid base64url data");
+      return;
+    }
+    // Sanity check: validate timing values are within reasonable bounds
+    constexpr int32_t max_timing_us = 500000;  // 500ms absolute max
+    for (int32_t timing : transmit_data->get_data()) {
+      int32_t abs_timing = timing < 0 ? -timing : timing;
+      if (abs_timing > max_timing_us) {
+        ESP_LOGE(TAG, "Invalid timing value: %d µs (max %d)", timing, max_timing_us);
+        return;
+      }
+    }
+    ESP_LOGD(TAG, "Transmitting base64url raw timings: count=%zu, repeat=%u", transmit_data->get_data().size(),
+             call.get_repeat_count());
   } else {
     // From vector (lambdas/automations)
     transmit_data->set_data(call.get_raw_timings());

esphome/components/infrared/infrared.h

@@ -28,12 +28,29 @@ class InfraredCall {
 
   /// Set the carrier frequency in Hz
   InfraredCall &set_carrier_frequency(uint32_t frequency);
-  /// Set the raw timings (positive = mark, negative = space)
-  /// Note: The timings vector must outlive the InfraredCall (zero-copy reference)
+
+  // ===== Raw Timings Methods =====
+  // All set_raw_timings_* methods store pointers/references to external data.
+  // The referenced data must remain valid until perform() completes.
+  // Safe pattern:   call.set_raw_timings_xxx(data); call.perform();  // synchronous
+  // Unsafe pattern: call.set_raw_timings_xxx(data); defer([call]() { call.perform(); });  // data may be gone!
+
+  /// Set the raw timings from a vector (positive = mark, negative = space)
+  /// @note Lifetime: Stores a pointer to the vector. The vector must outlive perform().
+  /// @note Usage: Primarily for lambdas/automations where the vector is in scope.
   InfraredCall &set_raw_timings(const std::vector<int32_t> &timings);
-  /// Set the raw timings from packed protobuf sint32 data (zero-copy from wire)
-  /// Note: The data must outlive the InfraredCall
+
+  /// Set the raw timings from base64url-encoded little-endian int32 data
+  /// @note Lifetime: Stores a pointer to the string. The string must outlive perform().
+  /// @note Usage: For web_server - base64url is fully URL-safe (uses '-' and '_').
+  /// @note Decoding happens at perform() time, directly into the transmit buffer.
+  InfraredCall &set_raw_timings_base64url(const std::string &base64url);
+
+  /// Set the raw timings from packed protobuf sint32 data (zigzag + varint encoded)
+  /// @note Lifetime: Stores a pointer to the buffer. The buffer must outlive perform().
+  /// @note Usage: For API component where data comes directly from the protobuf message.
   InfraredCall &set_raw_timings_packed(const uint8_t *data, uint16_t length, uint16_t count);
+
   /// Set the number of times to repeat transmission (1 = transmit once, 2 = transmit twice, etc.)
   InfraredCall &set_repeat_count(uint32_t count);
 
@@ -42,12 +59,18 @@ class InfraredCall {
 
   /// Get the carrier frequency
   const optional<uint32_t> &get_carrier_frequency() const { return this->carrier_frequency_; }
-  /// Get the raw timings (only valid if set via set_raw_timings, not packed)
+  /// Get the raw timings (only valid if set via set_raw_timings)
   const std::vector<int32_t> &get_raw_timings() const { return *this->raw_timings_; }
-  /// Check if raw timings have been set (either vector or packed)
-  bool has_raw_timings() const { return this->raw_timings_ != nullptr || this->packed_data_ != nullptr; }
+  /// Check if raw timings have been set (any format)
+  bool has_raw_timings() const {
+    return this->raw_timings_ != nullptr || this->packed_data_ != nullptr || this->base64url_ptr_ != nullptr;
+  }
   /// Check if using packed data format
   bool is_packed() const { return this->packed_data_ != nullptr; }
+  /// Check if using base64url data format
+  bool is_base64url() const { return this->base64url_ptr_ != nullptr; }
+  /// Get the base64url data string
+  const std::string &get_base64url_data() const { return *this->base64url_ptr_; }
   /// Get packed data (only valid if set via set_raw_timings_packed)
   const uint8_t *get_packed_data() const { return this->packed_data_; }
   uint16_t get_packed_length() const { return this->packed_length_; }
@@ -59,9 +82,11 @@ class InfraredCall {
   uint32_t repeat_count_{1};
   Infrared *parent_;
   optional<uint32_t> carrier_frequency_;
-  // Vector-based timings (for lambdas/automations)
+  // Pointer to vector-based timings (caller-owned, must outlive perform())
   const std::vector<int32_t> *raw_timings_{nullptr};
-  // Packed protobuf timings (for API zero-copy)
+  // Pointer to base64url-encoded string (caller-owned, must outlive perform())
+  const std::string *base64url_ptr_{nullptr};
+  // Pointer to packed protobuf buffer (caller-owned, must outlive perform())
   const uint8_t *packed_data_{nullptr};
   uint16_t packed_length_{0};
   uint16_t packed_count_{0};

esphome/components/json/__init__.py

@@ -1,6 +1,6 @@
 import esphome.codegen as cg
 import esphome.config_validation as cv
-from esphome.core import CoroPriority, coroutine_with_priority
+from esphome.core import CORE, CoroPriority, coroutine_with_priority
 
 CODEOWNERS = ["@esphome/core"]
 json_ns = cg.esphome_ns.namespace("json")
@@ -12,6 +12,11 @@ CONFIG_SCHEMA = cv.All(
 
 @coroutine_with_priority(CoroPriority.BUS)
 async def to_code(config):
-    cg.add_library("bblanchon/ArduinoJson", "7.4.2")
+    if CORE.is_esp32:
+        from esphome.components.esp32 import add_idf_component
+
+        add_idf_component(name="bblanchon/arduinojson", ref="7.4.2")
+    else:
+        cg.add_library("bblanchon/ArduinoJson", "7.4.2")
     cg.add_define("USE_JSON")
     cg.add_global(json_ns.using)

esphome/components/libretiny/__init__.py

@@ -382,4 +382,11 @@ async def component_to_code(config):
             "custom_options.sys_config#h", _BK7231N_SYS_CONFIG_OPTIONS
         )
 
+    # Disable LWIP statistics to save RAM - not needed in production
+    # Must explicitly disable all sub-stats to avoid redefinition warnings
+    cg.add_platformio_option(
+        "custom_options.lwip",
+        ["LWIP_STATS=0", "MEM_STATS=0", "MEMP_STATS=0"],
+    )
+
     await cg.register_component(var, config)

esphome/components/libretiny/preferences.cpp

@@ -166,8 +166,8 @@ class LibreTinyPreferences : public ESPPreferences {
       return true;
     }
 
-    // Allocate buffer on heap to avoid stack allocation for large data
-    auto stored_data = std::make_unique<uint8_t[]>(kv.value_len);
+    // Most preferences are small, use stack buffer with heap fallback for large ones
+    SmallBufferWithHeapFallback<256> stored_data(kv.value_len);
     fdb_blob_make(&this->blob, stored_data.get(), kv.value_len);
     size_t actual_len = fdb_kv_get_blob(db, key_str, &this->blob);
     if (actual_len != kv.value_len) {

esphome/components/light/light_json_schema.cpp

@@ -1,4 +1,5 @@
 #include "light_json_schema.h"
+#include "color_mode.h"
 #include "light_output.h"
 #include "esphome/core/progmem.h"
 
@@ -8,29 +9,32 @@ namespace esphome::light {
 
 // See https://www.home-assistant.io/integrations/light.mqtt/#json-schema for documentation on the schema
 
-// Get JSON string for color mode using linear search (avoids large switch jump table)
-static const char *get_color_mode_json_str(ColorMode mode) {
-  // Parallel arrays: mode values and their corresponding strings
-  // Uses less RAM than a switch jump table on sparse enum values
-  static constexpr ColorMode MODES[] = {
-      ColorMode::ON_OFF,
-      ColorMode::BRIGHTNESS,
-      ColorMode::WHITE,
-      ColorMode::COLOR_TEMPERATURE,
-      ColorMode::COLD_WARM_WHITE,
-      ColorMode::RGB,
-      ColorMode::RGB_WHITE,
-      ColorMode::RGB_COLOR_TEMPERATURE,
-      ColorMode::RGB_COLD_WARM_WHITE,
-  };
-  static constexpr const char *STRINGS[] = {
-      "onoff", "brightness", "white", "color_temp", "cwww", "rgb", "rgbw", "rgbct", "rgbww",
-  };
-  for (size_t i = 0; i < sizeof(MODES) / sizeof(MODES[0]); i++) {
-    if (MODES[i] == mode)
-      return STRINGS[i];
+// Get JSON string for color mode.
+// ColorMode enum values are sparse bitmasks (0, 1, 3, 7, 11, 19, 35, 39, 47, 51) which would
+// generate a large jump table. Converting to bit index (0-9) allows a compact switch.
+static ProgmemStr get_color_mode_json_str(ColorMode mode) {
+  switch (ColorModeBitPolicy::to_bit(mode)) {
+    case 1:
+      return ESPHOME_F("onoff");
+    case 2:
+      return ESPHOME_F("brightness");
+    case 3:
+      return ESPHOME_F("white");
+    case 4:
+      return ESPHOME_F("color_temp");
+    case 5:
+      return ESPHOME_F("cwww");
+    case 6:
+      return ESPHOME_F("rgb");
+    case 7:
+      return ESPHOME_F("rgbw");
+    case 8:
+      return ESPHOME_F("rgbct");
+    case 9:
+      return ESPHOME_F("rgbww");
+    default:
+      return nullptr;
   }
-  return nullptr;
 }
 
 void LightJSONSchema::dump_json(LightState &state, JsonObject root) {
@@ -44,7 +48,7 @@ void LightJSONSchema::dump_json(LightState &state, JsonObject root) {
   auto values = state.remote_values;
 
   const auto color_mode = values.get_color_mode();
-  const char *mode_str = get_color_mode_json_str(color_mode);
+  const auto *mode_str = get_color_mode_json_str(color_mode);
   if (mode_str != nullptr) {
     root[ESPHOME_F("color_mode")] = mode_str;
   }

esphome/components/lightwaverf/lightwaverf.cpp

@@ -1,3 +1,4 @@
+#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
 #ifdef USE_ESP8266
@@ -44,13 +45,16 @@ void LightWaveRF::send_rx(const std::vector<uint8_t> &msg, uint8_t repeats, bool
 }
 
 void LightWaveRF::print_msg_(uint8_t *msg, uint8_t len) {
-  char buffer[65];
+#if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_DEBUG
+  char buffer[65];  // max 10 entries * 6 chars + null
   ESP_LOGD(TAG, " Received code (len:%i): ", len);
 
+  size_t pos = 0;
   for (int i = 0; i < len; i++) {
-    sprintf(&buffer[i * 6], "0x%02x, ", msg[i]);
+    pos = buf_append_printf(buffer, sizeof(buffer), pos, "0x%02x, ", msg[i]);
   }
   ESP_LOGD(TAG, "[%s]", buffer);
+#endif
 }
 
 void LightWaveRF::dump_config() {

esphome/components/lock/lock.cpp

@@ -28,16 +28,14 @@ const LogString *lock_state_to_string(LockState state) {
 Lock::Lock() : state(LOCK_STATE_NONE) {}
 LockCall Lock::make_call() { return LockCall(this); }
 
-void Lock::lock() {
+void Lock::set_state_(LockState state) {
   auto call = this->make_call();
-  call.set_state(LOCK_STATE_LOCKED);
-  this->control(call);
-}
-void Lock::unlock() {
-  auto call = this->make_call();
-  call.set_state(LOCK_STATE_UNLOCKED);
+  call.set_state(state);
   this->control(call);
 }
+
+void Lock::lock() { this->set_state_(LOCK_STATE_LOCKED); }
+void Lock::unlock() { this->set_state_(LOCK_STATE_UNLOCKED); }
 void Lock::open() {
   if (traits.get_supports_open()) {
     ESP_LOGD(TAG, "'%s' Opening.", this->get_name().c_str());

esphome/components/lock/lock.h

@@ -156,6 +156,9 @@ class Lock : public EntityBase {
  protected:
   friend LockCall;
 
+  /// Helper for lock/unlock convenience methods
+  void set_state_(LockState state);
+
   /** Perform the open latch action with hardware. This method is optional to implement
    * when creating a new lock.
    *

esphome/components/logger/logger.cpp

@@ -1,8 +1,5 @@
 #include "logger.h"
 #include <cinttypes>
-#ifdef USE_ESPHOME_TASK_LOG_BUFFER
-#include <memory>  // For unique_ptr
-#endif
 
 #include "esphome/core/application.h"
 #include "esphome/core/hal.h"
@@ -199,7 +196,8 @@ inline uint8_t Logger::level_for(const char *tag) {
 
 Logger::Logger(uint32_t baud_rate, size_t tx_buffer_size) : baud_rate_(baud_rate), tx_buffer_size_(tx_buffer_size) {
   // add 1 to buffer size for null terminator
-  this->tx_buffer_ = new char[this->tx_buffer_size_ + 1];  // NOLINT
+  // NOLINTNEXTLINE(cppcoreguidelines-owning-memory) - allocated once, never freed
+  this->tx_buffer_ = new char[this->tx_buffer_size_ + 1];
 #if defined(USE_ESP32) || defined(USE_LIBRETINY)
   this->main_task_ = xTaskGetCurrentTaskHandle();
 #elif defined(USE_ZEPHYR)
@@ -212,11 +210,14 @@ Logger::Logger(uint32_t baud_rate, size_t tx_buffer_size) : baud_rate_(baud_rate
 void Logger::init_log_buffer(size_t total_buffer_size) {
 #ifdef USE_HOST
   // Host uses slot count instead of byte size
-  this->log_buffer_ = esphome::make_unique<logger::TaskLogBufferHost>(total_buffer_size);
+  // NOLINTNEXTLINE(cppcoreguidelines-owning-memory) - allocated once, never freed
+  this->log_buffer_ = new logger::TaskLogBufferHost(total_buffer_size);
 #elif defined(USE_ESP32)
-  this->log_buffer_ = esphome::make_unique<logger::TaskLogBuffer>(total_buffer_size);
+  // NOLINTNEXTLINE(cppcoreguidelines-owning-memory) - allocated once, never freed
+  this->log_buffer_ = new logger::TaskLogBuffer(total_buffer_size);
 #elif defined(USE_LIBRETINY)
-  this->log_buffer_ = esphome::make_unique<logger::TaskLogBufferLibreTiny>(total_buffer_size);
+  // NOLINTNEXTLINE(cppcoreguidelines-owning-memory) - allocated once, never freed
+  this->log_buffer_ = new logger::TaskLogBufferLibreTiny(total_buffer_size);
 #endif
 
 #if defined(USE_ESP32) || defined(USE_LIBRETINY)

esphome/components/logger/logger.h

@@ -412,11 +412,11 @@ class Logger : public Component {
 #endif
 #ifdef USE_ESPHOME_TASK_LOG_BUFFER
 #ifdef USE_HOST
-  std::unique_ptr<logger::TaskLogBufferHost> log_buffer_;  // Will be initialized with init_log_buffer
+  logger::TaskLogBufferHost *log_buffer_{nullptr};  // Allocated once, never freed
 #elif defined(USE_ESP32)
-  std::unique_ptr<logger::TaskLogBuffer> log_buffer_;  // Will be initialized with init_log_buffer
+  logger::TaskLogBuffer *log_buffer_{nullptr};  // Allocated once, never freed
 #elif defined(USE_LIBRETINY)
-  std::unique_ptr<logger::TaskLogBufferLibreTiny> log_buffer_;  // Will be initialized with init_log_buffer
+  logger::TaskLogBufferLibreTiny *log_buffer_{nullptr};  // Allocated once, never freed
 #endif
 #endif
 

esphome/components/lvgl/lv_validation.py

@@ -413,6 +413,7 @@ class TextValidator(LValidator):
                 str_args = [str(x) for x in value[CONF_ARGS]]
                 arg_expr = cg.RawExpression(",".join(str_args))
                 format_str = cpp_string_escape(format_str)
+                # str_sprintf justified: user-defined format, can't optimize without permanent RAM cost
                 sprintf_str = f"str_sprintf({format_str}, {arg_expr}).c_str()"
                 if nanval := value.get(CONF_IF_NAN):
                     nanval = cpp_string_escape(nanval)

esphome/components/lvgl/lvgl_esphome.cpp

@@ -65,7 +65,10 @@ std::string lv_event_code_name_for(uint8_t event_code) {
   if (event_code < sizeof(EVENT_NAMES) / sizeof(EVENT_NAMES[0])) {
     return EVENT_NAMES[event_code];
   }
-  return str_sprintf("%2d", event_code);
+  // max 4 bytes: "%u" with uint8_t (max 255, 3 digits) + null
+  char buf[4];
+  snprintf(buf, sizeof(buf), "%u", event_code);
+  return buf;
 }
 
 static void rounder_cb(lv_disp_drv_t *disp_drv, lv_area_t *area) {

esphome/components/mapping/mapping.h

@@ -2,6 +2,7 @@
 
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
+#include <cinttypes>
 #include <map>
 #include <string>
 
@@ -43,8 +44,17 @@ template<typename K, typename V> class Mapping {
       esph_log_e(TAG, "Key '%p' not found in mapping", key);
     } else if constexpr (std::is_same_v<K, std::string>) {
       esph_log_e(TAG, "Key '%s' not found in mapping", key.c_str());
+    } else if constexpr (std::is_integral_v<K>) {
+      char buf[24];  // enough for 64-bit integer
+      if constexpr (std::is_unsigned_v<K>) {
+        buf_append_printf(buf, sizeof(buf), 0, "%" PRIu64, static_cast<uint64_t>(key));
+      } else {
+        buf_append_printf(buf, sizeof(buf), 0, "%" PRId64, static_cast<int64_t>(key));
+      }
+      esph_log_e(TAG, "Key '%s' not found in mapping", buf);
     } else {
-      esph_log_e(TAG, "Key '%s' not found in mapping", to_string(key).c_str());
+      // All supported key types are handled above - this should never be reached
+      static_assert(sizeof(K) == 0, "Unsupported key type for Mapping error logging");
     }
     return {};
   }

esphome/components/max6956/max6956.cpp

@@ -162,7 +162,7 @@ void MAX6956GPIOPin::pin_mode(gpio::Flags flags) { this->parent_->pin_mode(this-
 bool MAX6956GPIOPin::digital_read() { return this->parent_->digital_read(this->pin_) != this->inverted_; }
 void MAX6956GPIOPin::digital_write(bool value) { this->parent_->digital_write(this->pin_, value != this->inverted_); }
 size_t MAX6956GPIOPin::dump_summary(char *buffer, size_t len) const {
-  return snprintf(buffer, len, "%u via Max6956", this->pin_);
+  return buf_append_printf(buffer, len, 0, "%u via Max6956", this->pin_);
 }
 
 }  // namespace max6956

esphome/components/mcp23016/mcp23016.cpp

@@ -100,7 +100,7 @@ void MCP23016GPIOPin::pin_mode(gpio::Flags flags) { this->parent_->pin_mode(this
 bool MCP23016GPIOPin::digital_read() { return this->parent_->digital_read(this->pin_) != this->inverted_; }
 void MCP23016GPIOPin::digital_write(bool value) { this->parent_->digital_write(this->pin_, value != this->inverted_); }
 size_t MCP23016GPIOPin::dump_summary(char *buffer, size_t len) const {
-  return snprintf(buffer, len, "%u via MCP23016", this->pin_);
+  return buf_append_printf(buffer, len, 0, "%u via MCP23016", this->pin_);
 }
 
 }  // namespace mcp23016

esphome/components/mcp23xxx_base/mcp23xxx_base.cpp

@@ -17,7 +17,7 @@ template<uint8_t N> void MCP23XXXGPIOPin<N>::digital_write(bool value) {
   this->parent_->digital_write(this->pin_, value != this->inverted_);
 }
 template<uint8_t N> size_t MCP23XXXGPIOPin<N>::dump_summary(char *buffer, size_t len) const {
-  return snprintf(buffer, len, "%u via MCP23XXX", this->pin_);
+  return buf_append_printf(buffer, len, 0, "%u via MCP23XXX", this->pin_);
 }
 
 template class MCP23XXXGPIOPin<8>;

esphome/components/mdns/mdns_esp32.cpp

@@ -24,13 +24,14 @@ static void register_esp32(MDNSComponent *comp, StaticVector<MDNSService, MDNS_S
   mdns_instance_name_set(hostname);
 
   for (const auto &service : services) {
-    auto txt_records = std::make_unique<mdns_txt_item_t[]>(service.txt_records.size());
+    // Stack buffer for up to 16 txt records, heap fallback for more
+    SmallBufferWithHeapFallback<16, mdns_txt_item_t> txt_records(service.txt_records.size());
     for (size_t i = 0; i < service.txt_records.size(); i++) {
       const auto &record = service.txt_records[i];
       // key and value are either compile-time string literals in flash or pointers to dynamic_txt_values_
       // Both remain valid for the lifetime of this function, and ESP-IDF makes internal copies
-      txt_records[i].key = MDNS_STR_ARG(record.key);
-      txt_records[i].value = MDNS_STR_ARG(record.value);
+      txt_records.get()[i].key = MDNS_STR_ARG(record.key);
+      txt_records.get()[i].value = MDNS_STR_ARG(record.value);
     }
     uint16_t port = const_cast<TemplatableValue<uint16_t> &>(service.port).value();
     err = mdns_service_add(nullptr, MDNS_STR_ARG(service.service_type), MDNS_STR_ARG(service.proto), port,

esphome/components/mipi_dsi/models/guition.py

@@ -101,4 +101,225 @@ DriverChip(
         (0xFF, 0x77, 0x01, 0x00, 0x00, 0x00),
     ]
 )
+
+# jc8012P4A1 Driver Configuration (jd9365)
+# Using parameters from esp_lcd_jd9365.h and the working full init sequence
+# ----------------------------------------------------------------------------------------------------------------------
+# * Resolution: 800x1280
+# * PCLK Frequency: 60 MHz
+# * DSI Lane Bit Rate: 1 Gbps (using 2-Lane DSI configuration)
+# * Horizontal Timing (hsync_pulse_width=20, hsync_back_porch=20, hsync_front_porch=40)
+# * Vertical Timing (vsync_pulse_width=4, vsync_back_porch=8, vsync_front_porch=20)
+# ----------------------------------------------------------------------------------------------------------------------
+DriverChip(
+    "JC8012P4A1",
+    width=800,
+    height=1280,
+    hsync_back_porch=20,
+    hsync_pulse_width=20,
+    hsync_front_porch=40,
+    vsync_back_porch=8,
+    vsync_pulse_width=4,
+    vsync_front_porch=20,
+    pclk_frequency="60MHz",
+    lane_bit_rate="1Gbps",
+    swap_xy=cv.UNDEFINED,
+    color_order="RGB",
+    reset_pin=27,
+    initsequence=[
+        (0xE0, 0x00),
+        (0xE1, 0x93),
+        (0xE2, 0x65),
+        (0xE3, 0xF8),
+        (0x80, 0x01),
+        (0xE0, 0x01),
+        (0x00, 0x00),
+        (0x01, 0x39),
+        (0x03, 0x10),
+        (0x04, 0x41),
+        (0x0C, 0x74),
+        (0x17, 0x00),
+        (0x18, 0xD7),
+        (0x19, 0x00),
+        (0x1A, 0x00),
+        (0x1B, 0xD7),
+        (0x1C, 0x00),
+        (0x24, 0xFE),
+        (0x35, 0x26),
+        (0x37, 0x69),
+        (0x38, 0x05),
+        (0x39, 0x06),
+        (0x3A, 0x08),
+        (0x3C, 0x78),
+        (0x3D, 0xFF),
+        (0x3E, 0xFF),
+        (0x3F, 0xFF),
+        (0x40, 0x06),
+        (0x41, 0xA0),
+        (0x43, 0x14),
+        (0x44, 0x0B),
+        (0x45, 0x30),
+        (0x4B, 0x04),
+        (0x55, 0x02),
+        (0x57, 0x89),
+        (0x59, 0x0A),
+        (0x5A, 0x28),
+        (0x5B, 0x15),
+        (0x5D, 0x50),
+        (0x5E, 0x37),
+        (0x5F, 0x29),
+        (0x60, 0x1E),
+        (0x61, 0x1D),
+        (0x62, 0x12),
+        (0x63, 0x1A),
+        (0x64, 0x08),
+        (0x65, 0x25),
+        (0x66, 0x26),
+        (0x67, 0x28),
+        (0x68, 0x49),
+        (0x69, 0x3A),
+        (0x6A, 0x43),
+        (0x6B, 0x3A),
+        (0x6C, 0x3B),
+        (0x6D, 0x32),
+        (0x6E, 0x1F),
+        (0x6F, 0x0E),
+        (0x70, 0x50),
+        (0x71, 0x37),
+        (0x72, 0x29),
+        (0x73, 0x1E),
+        (0x74, 0x1D),
+        (0x75, 0x12),
+        (0x76, 0x1A),
+        (0x77, 0x08),
+        (0x78, 0x25),
+        (0x79, 0x26),
+        (0x7A, 0x28),
+        (0x7B, 0x49),
+        (0x7C, 0x3A),
+        (0x7D, 0x43),
+        (0x7E, 0x3A),
+        (0x7F, 0x3B),
+        (0x80, 0x32),
+        (0x81, 0x1F),
+        (0x82, 0x0E),
+        (0xE0, 0x02),
+        (0x00, 0x1F),
+        (0x01, 0x1F),
+        (0x02, 0x52),
+        (0x03, 0x51),
+        (0x04, 0x50),
+        (0x05, 0x4B),
+        (0x06, 0x4A),
+        (0x07, 0x49),
+        (0x08, 0x48),
+        (0x09, 0x47),
+        (0x0A, 0x46),
+        (0x0B, 0x45),
+        (0x0C, 0x44),
+        (0x0D, 0x40),
+        (0x0E, 0x41),
+        (0x0F, 0x1F),
+        (0x10, 0x1F),
+        (0x11, 0x1F),
+        (0x12, 0x1F),
+        (0x13, 0x1F),
+        (0x14, 0x1F),
+        (0x15, 0x1F),
+        (0x16, 0x1F),
+        (0x17, 0x1F),
+        (0x18, 0x52),
+        (0x19, 0x51),
+        (0x1A, 0x50),
+        (0x1B, 0x4B),
+        (0x1C, 0x4A),
+        (0x1D, 0x49),
+        (0x1E, 0x48),
+        (0x1F, 0x47),
+        (0x20, 0x46),
+        (0x21, 0x45),
+        (0x22, 0x44),
+        (0x23, 0x40),
+        (0x24, 0x41),
+        (0x25, 0x1F),
+        (0x26, 0x1F),
+        (0x27, 0x1F),
+        (0x28, 0x1F),
+        (0x29, 0x1F),
+        (0x2A, 0x1F),
+        (0x2B, 0x1F),
+        (0x2C, 0x1F),
+        (0x2D, 0x1F),
+        (0x2E, 0x52),
+        (0x2F, 0x40),
+        (0x30, 0x41),
+        (0x31, 0x48),
+        (0x32, 0x49),
+        (0x33, 0x4A),
+        (0x34, 0x4B),
+        (0x35, 0x44),
+        (0x36, 0x45),
+        (0x37, 0x46),
+        (0x38, 0x47),
+        (0x39, 0x51),
+        (0x3A, 0x50),
+        (0x3B, 0x1F),
+        (0x3C, 0x1F),
+        (0x3D, 0x1F),
+        (0x3E, 0x1F),
+        (0x3F, 0x1F),
+        (0x40, 0x1F),
+        (0x41, 0x1F),
+        (0x42, 0x1F),
+        (0x43, 0x1F),
+        (0x44, 0x52),
+        (0x45, 0x40),
+        (0x46, 0x41),
+        (0x47, 0x48),
+        (0x48, 0x49),
+        (0x49, 0x4A),
+        (0x4A, 0x4B),
+        (0x4B, 0x44),
+        (0x4C, 0x45),
+        (0x4D, 0x46),
+        (0x4E, 0x47),
+        (0x4F, 0x51),
+        (0x50, 0x50),
+        (0x51, 0x1F),
+        (0x52, 0x1F),
+        (0x53, 0x1F),
+        (0x54, 0x1F),
+        (0x55, 0x1F),
+        (0x56, 0x1F),
+        (0x57, 0x1F),
+        (0x58, 0x40),
+        (0x59, 0x00),
+        (0x5A, 0x00),
+        (0x5B, 0x10),
+        (0x5C, 0x05),
+        (0x5D, 0x50),
+        (0x5E, 0x01),
+        (0x5F, 0x02),
+        (0x60, 0x50),
+        (0x61, 0x06),
+        (0x62, 0x04),
+        (0x63, 0x03),
+        (0x64, 0x64),
+        (0x65, 0x65),
+        (0x66, 0x0B),
+        (0x67, 0x73),
+        (0x68, 0x07),
+        (0x69, 0x06),
+        (0x6A, 0x64),
+        (0x6B, 0x08),
+        (0x6C, 0x00),
+        (0x6D, 0x32),
+        (0x6E, 0x08),
+        (0xE0, 0x04),
+        (0x2C, 0x6B),
+        (0x35, 0x08),
+        (0x37, 0x00),
+        (0xE0, 0x00),
+    ]
+)
 # fmt: on

esphome/components/mipi_spi/mipi_spi.h

@@ -224,12 +224,9 @@ class MipiSpi : public display::Display,
                     this->madctl_ & MADCTL_BGR ? "BGR" : "RGB", DISPLAYPIXEL * 8, IS_BIG_ENDIAN ? "Big" : "Little");
     if (this->brightness_.has_value())
       esph_log_config(TAG, "  Brightness: %u", this->brightness_.value());
-    if (this->cs_ != nullptr)
-      esph_log_config(TAG, "  CS Pin: %s", this->cs_->dump_summary().c_str());
-    if (this->reset_pin_ != nullptr)
-      esph_log_config(TAG, "  Reset Pin: %s", this->reset_pin_->dump_summary().c_str());
-    if (this->dc_pin_ != nullptr)
-      esph_log_config(TAG, "  DC Pin: %s", this->dc_pin_->dump_summary().c_str());
+    log_pin(TAG, "  CS Pin: ", this->cs_);
+    log_pin(TAG, "  Reset Pin: ", this->reset_pin_);
+    log_pin(TAG, "  DC Pin: ", this->dc_pin_);
     esph_log_config(TAG,
                     "  SPI Mode: %d\n"
                     "  SPI Data rate: %dMHz\n"

esphome/components/mipi_spi/models/adafruit.py

@@ -26,5 +26,3 @@ ST7789V.extend(
     reset_pin=40,
     invert_colors=True,
 )
-
-models = {}

esphome/components/mipi_spi/models/amoled.py

@@ -105,6 +105,3 @@ CO5300 = DriverChip(
         (WCE, 0x00),
     ),
 )
-
-
-models = {}

esphome/components/mipi_spi/models/cyd.py

@@ -1,10 +1,45 @@
-from .ili import ILI9341
+from .ili import ILI9341, ILI9342, ST7789V
 
 ILI9341.extend(
+    # ESP32-2432S028 CYD board with Micro USB, has ILI9341 controller
     "ESP32-2432S028",
     data_rate="40MHz",
-    cs_pin=15,
-    dc_pin=2,
+    cs_pin={"number": 15, "ignore_strapping_warning": True},
+    dc_pin={"number": 2, "ignore_strapping_warning": True},
 )
 
-models = {}
+ST7789V.extend(
+    # ESP32-2432S028 CYD board with USB C + Micro USB, has ST7789V controller
+    "ESP32-2432S028-7789",
+    data_rate="40MHz",
+    cs_pin={"number": 15, "ignore_strapping_warning": True},
+    dc_pin={"number": 2, "ignore_strapping_warning": True},
+)
+
+# fmt: off
+
+ILI9342.extend(
+    # ESP32-2432S028 CYD board with USB C + Micro USB, has ILI9342 controller
+    "ESP32-2432S028-9342",
+    data_rate="40MHz",
+    cs_pin={"number": 15, "ignore_strapping_warning": True},
+    dc_pin={"number": 2, "ignore_strapping_warning": True},
+    initsequence=(
+        (0xCB, 0x39, 0x2C, 0x00, 0x34, 0x02),  # Power Control A
+        (0xCF, 0x00, 0xC1, 0x30),  # Power Control B
+        (0xE8, 0x85, 0x00, 0x78),  # Driver timing control A
+        (0xEA, 0x00, 0x00),  # Driver timing control B
+        (0xED, 0x64, 0x03, 0x12, 0x81),  # Power on sequence control
+        (0xF7, 0x20),  # Pump ratio control
+        (0xC0, 0x23),  # Power Control 1
+        (0xC1, 0x10),  # Power Control 2
+        (0xC5, 0x3E, 0x28),  # VCOM Control 1
+        (0xC7, 0x86),  # VCOM Control 2
+        (0xB1, 0x00, 0x1B),  # Frame Rate Control
+        (0xB6, 0x0A, 0xA2, 0x27, 0x00),  # Display Function Control
+        (0xF2, 0x00),  # Enable 3G
+        (0x26, 0x01),  # Gamma Set
+        (0xE0, 0x00, 0x0C, 0x11, 0x04, 0x11, 0x08, 0x37, 0x89, 0x4C, 0x06, 0x0C, 0x0A, 0x2E, 0x34, 0x0F),  # Positive Gamma Correction
+        (0xE1, 0x00, 0x0B, 0x11, 0x05, 0x13, 0x09, 0x33, 0x67, 0x48, 0x07, 0x0E, 0x0B, 0x23, 0x33, 0x0F),  # Negative Gamma Correction
+    )
+)

esphome/components/mipi_spi/models/ili.py

@@ -148,6 +148,34 @@ ILI9341 = DriverChip(
         ),
     ),
 )
+
+# fmt: off
+
+ILI9342 = DriverChip(
+    "ILI9342",
+    width=320,
+    height=240,
+    mirror_x=True,
+    initsequence=(
+        (0xCB, 0x39, 0x2C, 0x00, 0x34, 0x02),  # Power Control A
+        (0xCF, 0x00, 0xC1, 0x30),  # Power Control B
+        (0xE8, 0x85, 0x00, 0x78),  # Driver timing control A
+        (0xEA, 0x00, 0x00),  # Driver timing control B
+        (0xED, 0x64, 0x03, 0x12, 0x81),  # Power on sequence control
+        (0xF7, 0x20),  # Pump ratio control
+        (0xC0, 0x23),  # Power Control 1
+        (0xC1, 0x10),  # Power Control 2
+        (0xC5, 0x3E, 0x28),  # VCOM Control 1
+        (0xC7, 0x86),  # VCOM Control 2
+        (0xB1, 0x00, 0x1B),  # Frame Rate Control
+        (0xB6, 0x0A, 0xA2, 0x27, 0x00),  # Display Function Control
+        (0xF2, 0x00),  # Enable 3G
+        (0x26, 0x01),  # Gamma Set
+        (0xE0, 0x0F, 0x1F, 0x1C, 0x0C, 0x0F, 0x08, 0x48, 0x98, 0x37, 0x0A, 0x13, 0x04, 0x11, 0x0D, 0x00),  # Positive Gamma
+        (0xE1, 0x0F, 0x32, 0x2E, 0x0B, 0x0D, 0x05, 0x47, 0x75, 0x37, 0x06, 0x10, 0x03, 0x24, 0x20, 0x00),  # Negative Gamma
+    ),
+)
+
 # M5Stack Core2 uses ILI9341 chip - mirror_x disabled for correct orientation
 ILI9341.extend(
     "M5CORE2",
@@ -758,5 +786,3 @@ ST7796.extend(
     dc_pin=0,
     invert_colors=True,
 )
-
-models = {}

esphome/components/mipi_spi/models/jc.py

@@ -588,5 +588,3 @@ DriverChip(
         (0x29, 0x00),
     ),
 )
-
-models = {}

esphome/components/mipi_spi/models/lanbon.py

@@ -11,5 +11,3 @@ ST7789V.extend(
     dc_pin=21,
     reset_pin=18,
 )
-
-models = {}

esphome/components/mipi_spi/models/lilygo.py

@@ -56,5 +56,3 @@ ST7796.extend(
     backlight_pin=48,
     invert_colors=True,
 )
-
-models = {}

esphome/components/modbus_controller/modbus_controller.h

@@ -271,24 +271,31 @@ class ServerRegister {
 
   // Formats a raw value into a string representation based on the value type for debugging
   std::string format_value(int64_t value) const {
+    // max 44: float with %.1f can be up to 42 chars (3.4e38 → 39 integer digits + sign + decimal + 1 digit)
+    // plus null terminator = 43, rounded to 44 for 4-byte alignment
+    char buf[44];
     switch (this->value_type) {
       case SensorValueType::U_WORD:
       case SensorValueType::U_DWORD:
       case SensorValueType::U_DWORD_R:
       case SensorValueType::U_QWORD:
       case SensorValueType::U_QWORD_R:
-        return std::to_string(static_cast<uint64_t>(value));
+        buf_append_printf(buf, sizeof(buf), 0, "%" PRIu64, static_cast<uint64_t>(value));
+        return buf;
       case SensorValueType::S_WORD:
       case SensorValueType::S_DWORD:
       case SensorValueType::S_DWORD_R:
       case SensorValueType::S_QWORD:
       case SensorValueType::S_QWORD_R:
-        return std::to_string(value);
+        buf_append_printf(buf, sizeof(buf), 0, "%" PRId64, value);
+        return buf;
       case SensorValueType::FP32_R:
       case SensorValueType::FP32:
-        return str_sprintf("%.1f", bit_cast<float>(static_cast<uint32_t>(value)));
+        buf_append_printf(buf, sizeof(buf), 0, "%.1f", bit_cast<float>(static_cast<uint32_t>(value)));
+        return buf;
       default:
-        return std::to_string(value);
+        buf_append_printf(buf, sizeof(buf), 0, "%" PRId64, value);
+        return buf;
     }
   }
 

esphome/components/modbus_controller/text_sensor/modbus_textsensor.cpp

@@ -16,12 +16,20 @@ void ModbusTextSensor::parse_and_publish(const std::vector<uint8_t> &data) {
   while ((items_left > 0) && index < data.size()) {
     uint8_t b = data[index];
     switch (this->encode_) {
-      case RawEncoding::HEXBYTES:
-        output_str += str_snprintf("%02x", 2, b);
+      case RawEncoding::HEXBYTES: {
+        // max 3: 2 hex digits + null
+        char hex_buf[3];
+        snprintf(hex_buf, sizeof(hex_buf), "%02x", b);
+        output_str += hex_buf;
         break;
-      case RawEncoding::COMMA:
-        output_str += str_sprintf(index != this->offset ? ",%d" : "%d", b);
+      }
+      case RawEncoding::COMMA: {
+        // max 5: optional ','(1) + uint8(3) + null, for both ",%d" and "%d"
+        char dec_buf[5];
+        snprintf(dec_buf, sizeof(dec_buf), index != this->offset ? ",%d" : "%d", b);
+        output_str += dec_buf;
         break;
+      }
       case RawEncoding::ANSI:
         if (b < 0x20)
           break;

esphome/components/mpr121/mpr121.cpp

@@ -154,7 +154,7 @@ void MPR121GPIOPin::digital_write(bool value) {
 }
 
 size_t MPR121GPIOPin::dump_summary(char *buffer, size_t len) const {
-  return snprintf(buffer, len, "ELE%u on MPR121", this->pin_);
+  return buf_append_printf(buffer, len, 0, "ELE%u on MPR121", this->pin_);
 }
 
 }  // namespace mpr121

esphome/components/mqtt/mqtt_client.cpp

@@ -5,6 +5,7 @@
 #include <utility>
 #include "esphome/components/network/util.h"
 #include "esphome/core/application.h"
+#include "esphome/core/entity_base.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include "esphome/core/version.h"
@@ -66,10 +67,13 @@ void MQTTClientComponent::setup() {
         "esphome/discover", [this](const std::string &topic, const std::string &payload) { this->send_device_info_(); },
         2);
 
-    std::string topic = "esphome/ping/";
-    topic.append(App.get_name());
+    // Format topic on stack - subscribe() copies it
+    // "esphome/ping/" (13) + name (ESPHOME_DEVICE_NAME_MAX_LEN) + null (1)
+    constexpr size_t ping_topic_buffer_size = 13 + ESPHOME_DEVICE_NAME_MAX_LEN + 1;
+    char ping_topic[ping_topic_buffer_size];
+    buf_append_printf(ping_topic, sizeof(ping_topic), 0, "esphome/ping/%s", App.get_name().c_str());
     this->subscribe(
-        topic, [this](const std::string &topic, const std::string &payload) { this->send_device_info_(); }, 2);
+        ping_topic, [this](const std::string &topic, const std::string &payload) { this->send_device_info_(); }, 2);
   }
 
   if (this->enable_on_boot_) {
@@ -81,8 +85,11 @@ void MQTTClientComponent::send_device_info_() {
   if (!this->is_connected() or !this->is_discovery_ip_enabled()) {
     return;
   }
-  std::string topic = "esphome/discover/";
-  topic.append(App.get_name());
+  // Format topic on stack to avoid heap allocation
+  // "esphome/discover/" (17) + name (ESPHOME_DEVICE_NAME_MAX_LEN) + null (1)
+  constexpr size_t topic_buffer_size = 17 + ESPHOME_DEVICE_NAME_MAX_LEN + 1;
+  char topic[topic_buffer_size];
+  buf_append_printf(topic, sizeof(topic), 0, "esphome/discover/%s", App.get_name().c_str());
 
   // NOLINTBEGIN(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
   this->publish_json(
@@ -396,6 +403,12 @@ void MQTTClientComponent::loop() {
 
         this->last_connected_ = now;
         this->resubscribe_subscriptions_();
+
+        // Process pending resends for all MQTT components centrally
+        // This is more efficient than each component polling in its own loop
+        for (MQTTComponent *component : this->children_) {
+          component->process_resend();
+        }
       }
       break;
   }
@@ -500,39 +513,49 @@ bool MQTTClientComponent::publish(const std::string &topic, const std::string &p
 
 bool MQTTClientComponent::publish(const std::string &topic, const char *payload, size_t payload_length, uint8_t qos,
                                   bool retain) {
-  return publish({.topic = topic, .payload = std::string(payload, payload_length), .qos = qos, .retain = retain});
+  return this->publish(topic.c_str(), payload, payload_length, qos, retain);
 }
 
 bool MQTTClientComponent::publish(const MQTTMessage &message) {
+  return this->publish(message.topic.c_str(), message.payload.c_str(), message.payload.length(), message.qos,
+                       message.retain);
+}
+bool MQTTClientComponent::publish_json(const std::string &topic, const json::json_build_t &f, uint8_t qos,
+                                       bool retain) {
+  return this->publish_json(topic.c_str(), f, qos, retain);
+}
+
+bool MQTTClientComponent::publish(const char *topic, const char *payload, size_t payload_length, uint8_t qos,
+                                  bool retain) {
   if (!this->is_connected()) {
-    // critical components will re-transmit their messages
     return false;
   }
-  bool logging_topic = this->log_message_.topic == message.topic;
-  bool ret = this->mqtt_backend_.publish(message);
+  size_t topic_len = strlen(topic);
+  bool logging_topic = (topic_len == this->log_message_.topic.size()) &&
+                       (memcmp(this->log_message_.topic.c_str(), topic, topic_len) == 0);
+  bool ret = this->mqtt_backend_.publish(topic, payload, payload_length, qos, retain);
   delay(0);
   if (!ret && !logging_topic && this->is_connected()) {
     delay(0);
-    ret = this->mqtt_backend_.publish(message);
+    ret = this->mqtt_backend_.publish(topic, payload, payload_length, qos, retain);
     delay(0);
   }
 
   if (!logging_topic) {
     if (ret) {
-      ESP_LOGV(TAG, "Publish(topic='%s' payload='%s' retain=%d qos=%d)", message.topic.c_str(), message.payload.c_str(),
-               message.retain, message.qos);
+      ESP_LOGV(TAG, "Publish(topic='%s' retain=%d qos=%d)", topic, retain, qos);
+      ESP_LOGVV(TAG, "Publish payload (len=%u): '%.*s'", payload_length, static_cast<int>(payload_length), payload);
     } else {
-      ESP_LOGV(TAG, "Publish failed for topic='%s' (len=%u). Will retry", message.topic.c_str(),
-               message.payload.length());
+      ESP_LOGV(TAG, "Publish failed for topic='%s' (len=%u). Will retry", topic, payload_length);
       this->status_momentary_warning("publish", 1000);
     }
   }
   return ret != 0;
 }
-bool MQTTClientComponent::publish_json(const std::string &topic, const json::json_build_t &f, uint8_t qos,
-                                       bool retain) {
+
+bool MQTTClientComponent::publish_json(const char *topic, const json::json_build_t &f, uint8_t qos, bool retain) {
   std::string message = json::build_json(f);
-  return this->publish(topic, message, qos, retain);
+  return this->publish(topic, message.c_str(), message.length(), qos, retain);
 }
 
 void MQTTClientComponent::enable() {
@@ -610,18 +633,10 @@ static bool topic_match(const char *message, const char *subscription) {
 }
 
 void MQTTClientComponent::on_message(const std::string &topic, const std::string &payload) {
-#ifdef USE_ESP8266
-  // on ESP8266, this is called in lwIP/AsyncTCP task; some components do not like running
-  // from a different task.
-  this->defer([this, topic, payload]() {
-#endif
-    for (auto &subscription : this->subscriptions_) {
-      if (topic_match(topic.c_str(), subscription.topic.c_str()))
-        subscription.callback(topic, payload);
-    }
-#ifdef USE_ESP8266
-  });
-#endif
+  for (auto &subscription : this->subscriptions_) {
+    if (topic_match(topic.c_str(), subscription.topic.c_str()))
+      subscription.callback(topic, payload);
+  }
 }
 
 // Setters
@@ -635,7 +650,8 @@ void MQTTClientComponent::set_log_message_template(MQTTMessage &&message) { this
 const MQTTDiscoveryInfo &MQTTClientComponent::get_discovery_info() const { return this->discovery_info_; }
 void MQTTClientComponent::set_topic_prefix(const std::string &topic_prefix, const std::string &check_topic_prefix) {
   if (App.is_name_add_mac_suffix_enabled() && (topic_prefix == check_topic_prefix)) {
-    this->topic_prefix_ = str_sanitize(App.get_name());
+    char buf[ESPHOME_DEVICE_NAME_MAX_LEN + 1];
+    this->topic_prefix_ = str_sanitize_to(buf, App.get_name().c_str());
   } else {
     this->topic_prefix_ = topic_prefix;
   }