bot concerns

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

@@ -1,96 +0,0 @@
----
-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@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+      uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
       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@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         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@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache/save@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         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: ${{ needs.common.outputs.cache-key }}
       - name: Restore components graph cache
-        uses: actions/cache/restore@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         with:
           path: .temp/components_graph.json
           key: components-graph-${{ hashFiles('esphome/components/**/*.py') }}
@@ -223,7 +223,7 @@ jobs:
           echo "component-test-batches=$(echo "$output" | jq -c '.component_test_batches')" >> $GITHUB_OUTPUT
       - name: Save components graph cache
         if: github.ref == 'refs/heads/dev'
-        uses: actions/cache/save@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache/save@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         with:
           path: .temp/components_graph.json
           key: components-graph-${{ hashFiles('esphome/components/**/*.py') }}
@@ -245,7 +245,7 @@ jobs:
           python-version: "3.13"
       - name: Restore Python virtual environment
         id: cache-venv
-        uses: actions/cache@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         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@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         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@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         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@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         with:
           path: ~/.platformio
           key: platformio-tidyesp32-${{ hashFiles('platformio.ini') }}
 
       - name: Cache platformio
         if: github.ref != 'refs/heads/dev'
-        uses: actions/cache/restore@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         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@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         with:
           path: ~/.platformio
           key: platformio-tidyesp32-${{ hashFiles('platformio.ini') }}
 
       - name: Cache platformio
         if: github.ref != 'refs/heads/dev'
-        uses: actions/cache/restore@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         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@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         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@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         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@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache/save@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         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: ${{ needs.common.outputs.cache-key }}
       - name: Cache platformio
-        uses: actions/cache/restore@8b402f58fbc84540c8b491a91e594a4576fec3d7 # v5.0.2
+        uses: actions/cache/restore@9255dc7a253b0ccc959486e2bca901246202afeb # v5.0.1
         with:
           path: ~/.platformio
           key: platformio-memory-${{ 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: v0.14.13
+    rev: v0.14.11
     hooks:
       # Run the linter.
       - id: ruff

esphome/__main__.py

@@ -1,6 +1,5 @@
 # PYTHON_ARGCOMPLETE_OK
 import argparse
-from collections.abc import Callable
 from datetime import datetime
 import functools
 import getpass
@@ -223,13 +222,8 @@ 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. "
-                f"Is the device connected to the network? {hint}"
+                f"All specified devices {defaults} could not be resolved. Is the device connected to the network?"
             )
         return resolved
 
@@ -937,21 +931,11 @@ def command_dashboard(args: ArgsProtocol) -> int | None:
     return dashboard.start_dashboard(args)
 
 
-def run_multiple_configs(
-    files: list, command_builder: Callable[[str], list[str]]
-) -> int:
-    """Run a command for each configuration file in a subprocess.
-
-    Args:
-        files: List of configuration files to process.
-        command_builder: Callable that takes a file path and returns a command list.
-
-    Returns:
-        Number of failed files.
-    """
+def command_update_all(args: ArgsProtocol) -> int | None:
     import click
 
     success = {}
+    files = list_yaml_files(args.configuration)
     twidth = 60
 
     def print_bar(middle_text):
@@ -961,19 +945,17 @@ def run_multiple_configs(
         safe_print(f"{half_line}{middle_text}{half_line}")
 
     for f in files:
-        f_path = Path(f) if not isinstance(f, Path) else f
-
-        if any(f_path.name == x for x in SECRETS_FILES):
-            _LOGGER.warning("Skipping secrets file %s", f_path)
-            continue
-
-        safe_print(f"Processing {color(AnsiFore.CYAN, str(f))}")
+        safe_print(f"Updating {color(AnsiFore.CYAN, str(f))}")
         safe_print("-" * twidth)
         safe_print()
-
-        cmd = command_builder(f)
-        rc = run_external_process(*cmd)
-
+        if CORE.dashboard:
+            rc = run_external_process(
+                "esphome", "--dashboard", "run", f, "--no-logs", "--device", "OTA"
+            )
+        else:
+            rc = run_external_process(
+                "esphome", "run", f, "--no-logs", "--device", "OTA"
+            )
         if rc == 0:
             print_bar(f"[{color(AnsiFore.BOLD_GREEN, 'SUCCESS')}] {str(f)}")
             success[f] = True
@@ -988,8 +970,6 @@ def run_multiple_configs(
     print_bar(f"[{color(AnsiFore.BOLD_WHITE, 'SUMMARY')}]")
     failed = 0
     for f in files:
-        if f not in success:
-            continue  # Skipped file
         if success[f]:
             safe_print(f"  - {str(f)}: {color(AnsiFore.GREEN, 'SUCCESS')}")
         else:
@@ -998,17 +978,6 @@ def run_multiple_configs(
     return failed
 
 
-def command_update_all(args: ArgsProtocol) -> int | None:
-    files = list_yaml_files(args.configuration)
-
-    def build_command(f):
-        if CORE.dashboard:
-            return ["esphome", "--dashboard", "run", f, "--no-logs", "--device", "OTA"]
-        return ["esphome", "run", f, "--no-logs", "--device", "OTA"]
-
-    return run_multiple_configs(files, build_command)
-
-
 def command_idedata(args: ArgsProtocol, config: ConfigType) -> int:
     import json
 
@@ -1559,48 +1528,38 @@ def run_esphome(argv):
 
     _LOGGER.info("ESPHome %s", const.__version__)
 
-    # Multiple configurations: use subprocesses to avoid state leakage
-    # between compilations (e.g., LVGL touchscreen state in module globals)
-    if len(args.configuration) > 1:
-        # Build command by reusing argv, replacing all configs with single file
-        # argv[0] is the program path, skip it since we prefix with "esphome"
-        def build_command(f):
-            return (
-                ["esphome"]
-                + [arg for arg in argv[1:] if arg not in args.configuration]
-                + [str(f)]
-            )
+    for conf_path in args.configuration:
+        conf_path = Path(conf_path)
+        if any(conf_path.name == x for x in SECRETS_FILES):
+            _LOGGER.warning("Skipping secrets file %s", conf_path)
+            continue
 
-        return run_multiple_configs(args.configuration, build_command)
+        CORE.config_path = conf_path
+        CORE.dashboard = args.dashboard
 
-    # Single configuration
-    conf_path = Path(args.configuration[0])
-    if any(conf_path.name == x for x in SECRETS_FILES):
-        _LOGGER.warning("Skipping secrets file %s", conf_path)
-        return 0
+        # For logs command, skip updating external components
+        skip_external = args.command == "logs"
+        config = read_config(
+            dict(args.substitution) if args.substitution else {},
+            skip_external_update=skip_external,
+        )
+        if config is None:
+            return 2
+        CORE.config = config
 
-    CORE.config_path = conf_path
-    CORE.dashboard = args.dashboard
+        if args.command not in POST_CONFIG_ACTIONS:
+            safe_print(f"Unknown command {args.command}")
 
-    # For logs command, skip updating external components
-    skip_external = args.command == "logs"
-    config = read_config(
-        dict(args.substitution) if args.substitution else {},
-        skip_external_update=skip_external,
-    )
-    if config is None:
-        return 2
-    CORE.config = config
+        try:
+            rc = POST_CONFIG_ACTIONS[args.command](args, config)
+        except EsphomeError as e:
+            _LOGGER.error(e, exc_info=args.verbose)
+            return 1
+        if rc != 0:
+            return rc
 
-    if args.command not in POST_CONFIG_ACTIONS:
-        safe_print(f"Unknown command {args.command}")
-        return 1
-
-    try:
-        return POST_CONFIG_ACTIONS[args.command](args, config)
-    except EsphomeError as e:
-        _LOGGER.error(e, exc_info=args.verbose)
-        return 1
+        CORE.reset()
+    return 0
 
 
 def main():

esphome/codegen.py

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

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;
-  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), "%s", CMD_READ_DEVICE_STATUS);
+  sprintf((char *) 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;
-  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), "%s", CMD_READ_TARGET_TEMP);
+  sprintf((char *) 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;
-  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), "%s", CMD_READ_CURRENT_TEMP);
+  sprintf((char *) this->packet_.data, "%s", CMD_READ_CURRENT_TEMP);
   return this->clean_packet_();
 }
 
 AnovaPacket *AnovaCodec::get_read_unit_request() {
   this->current_query_ = READ_UNIT;
-  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), "%s", CMD_READ_UNIT);
+  sprintf((char *) this->packet_.data, "%s", CMD_READ_UNIT);
   return this->clean_packet_();
 }
 
 AnovaPacket *AnovaCodec::get_read_data_request() {
   this->current_query_ = READ_DATA;
-  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), "%s", CMD_READ_DATA);
+  sprintf((char *) 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);
-  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), CMD_SET_TARGET_TEMP, temperature);
+  sprintf((char *) 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;
-  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), CMD_SET_TEMP_UNIT, unit);
+  sprintf((char *) this->packet_.data, CMD_SET_TEMP_UNIT, unit);
   return this->clean_packet_();
 }
 
 AnovaPacket *AnovaCodec::get_start_request() {
   this->current_query_ = START;
-  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), "%s", CMD_START);
+  sprintf((char *) this->packet_.data, CMD_START);
   return this->clean_packet_();
 }
 
 AnovaPacket *AnovaCodec::get_stop_request() {
   this->current_query_ = STOP;
-  snprintf((char *) this->packet_.data, sizeof(this->packet_.data), "%s", CMD_STOP);
+  sprintf((char *) this->packet_.data, CMD_STOP);
   return this->clean_packet_();
 }
 

esphome/components/api/api_connection.cpp

@@ -1712,16 +1712,17 @@ void APIConnection::on_home_assistant_state_response(const HomeAssistantStateRes
     }
 
     // Create null-terminated state for callback (parse_number needs null-termination)
-    // 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<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);
+    // HA state max length is 255, so 256 byte buffer covers all cases
+    char state_buf[256];
+    size_t copy_len = msg.state.size();
+    if (copy_len >= sizeof(state_buf)) {
+      copy_len = sizeof(state_buf) - 1;  // Truncate to leave space for null terminator
     }
-    state_buf[state_len] = '\0';
-    it.callback(StringRef(state_buf, state_len));
+    if (copy_len > 0) {
+      memcpy(state_buf, msg.state.c_str(), copy_len);
+    }
+    state_buf[copy_len] = '\0';
+    it.callback(StringRef(state_buf, copy_len));
   }
 }
 #endif

esphome/components/api/proto.cpp

@@ -48,14 +48,14 @@ uint32_t ProtoDecodableMessage::count_repeated_field(const uint8_t *buffer, size
         }
         uint32_t field_length = res->as_uint32();
         ptr += consumed;
-        if (field_length > static_cast<size_t>(end - ptr)) {
+        if (ptr + field_length > end) {
           return count;  // Out of bounds
         }
         ptr += field_length;
         break;
       }
       case WIRE_TYPE_FIXED32: {  // 32-bit - skip 4 bytes
-        if (end - ptr < 4) {
+        if (ptr + 4 > end) {
           return count;
         }
         ptr += 4;
@@ -110,7 +110,7 @@ void ProtoDecodableMessage::decode(const uint8_t *buffer, size_t length) {
         }
         uint32_t field_length = res->as_uint32();
         ptr += consumed;
-        if (field_length > static_cast<size_t>(end - ptr)) {
+        if (ptr + field_length > end) {
           ESP_LOGV(TAG, "Out-of-bounds Length Delimited at offset %ld", (long) (ptr - buffer));
           return;
         }
@@ -121,7 +121,7 @@ void ProtoDecodableMessage::decode(const uint8_t *buffer, size_t length) {
         break;
       }
       case WIRE_TYPE_FIXED32: {  // 32-bit
-        if (end - ptr < 4) {
+        if (ptr + 4 > end) {
           ESP_LOGV(TAG, "Out-of-bounds Fixed32-bit at offset %ld", (long) (ptr - buffer));
           return;
         }

esphome/components/atm90e32/atm90e32.cpp

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

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

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
-    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);
+    sprintf(version, "%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 buf_append_printf(buffer, len, 0, "EXIO%u via CH422G", this->pin_);
+  return snprintf(buffer, len, "EXIO%u via CH422G", this->pin_);
 }
 void CH422GGPIOPin::set_flags(gpio::Flags flags) {
   flags_ = flags;

esphome/components/cse7766/cse7766.cpp

@@ -207,24 +207,20 @@ void CSE7766Component::parse_data_() {
 
 #if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERY_VERBOSE
   {
-    // 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:");
+    std::string buf = "Parsed:";
     if (have_voltage) {
-      pos = buf_append_printf(buf, sizeof(buf), pos, " V=%.4fV", voltage);
+      buf += str_sprintf(" V=%fV", voltage);
     }
     if (have_current) {
-      pos = buf_append_printf(buf, sizeof(buf), pos, " I=%.4fmA (~%.4fmA)", current * 1000.0f,
-                              calculated_current * 1000.0f);
+      buf += str_sprintf(" I=%fmA (~%fmA)", current * 1000.0f, calculated_current * 1000.0f);
     }
     if (have_power) {
-      pos = buf_append_printf(buf, sizeof(buf), pos, " P=%.4fW", power);
+      buf += str_sprintf(" P=%fW", power);
     }
     if (energy != 0.0f) {
-      buf_append_printf(buf, sizeof(buf), pos, " E=%.4fkWh (%u)", energy, cf_pulses);
+      buf += str_sprintf(" E=%fkWh (%u)", energy, cf_pulses);
     }
-    ESP_LOGVV(TAG, "%s", buf);
+    ESP_LOGVV(TAG, "%s", buf.c_str());
   }
 #endif
 }

esphome/components/daikin_arc/daikin_arc.cpp

@@ -258,9 +258,8 @@ 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++) {
-    pos = buf_append_printf(buf, sizeof(buf), pos, "%02x ", frame[i]);
+    sprintf(buf, "%s%02x ", buf, frame[i]);
   }
   ESP_LOGD(TAG, "FRAME %s", buf);
 
@@ -350,9 +349,8 @@ 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;
-    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;
+    std::unique_ptr<char[]> buf(new char[bytes_count * 3 + 1]);
+    buf[0] = '\0';
     for (size_t i = 0; i < bytes_count; i++) {
       uint8_t byte = 0;
       for (int8_t bit = 0; bit < 8; bit++) {
@@ -363,19 +361,19 @@ bool DaikinArcClimate::on_receive(remote_base::RemoteReceiveData data) {
           break;
         }
       }
-      buf_pos = buf_append_printf(buf.get(), buf_size, buf_pos, "%02x ", byte);
+      sprintf(buf.get(), "%s%02x ", buf.get(), byte);
     }
     ESP_LOGD(TAG, "WHOLE FRAME %s  size: %d", buf.get(), data.size());
   }
   if (!valid_daikin_frame) {
-    char sbuf[16 * 10 + 1] = {0};
-    size_t sbuf_pos = 0;
+    char sbuf[16 * 10 + 1];
+    sbuf[0] = '\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_pos = 0;
+        sbuf[0] = '\0';
       }
       char type_ch = ' ';
       // debug_tolerance = 25%
@@ -403,10 +401,9 @@ bool DaikinArcClimate::on_receive(remote_base::RemoteReceiveData data) {
         type_ch = '0';
 
       if (abs(data[j]) > 100000) {
-        sbuf_pos = buf_append_printf(sbuf, sizeof(sbuf), sbuf_pos, "%-5d[%c] ", data[j] > 0 ? 99999 : -99999, type_ch);
+        sprintf(sbuf, "%s%-5d[%c] ", sbuf, data[j] > 0 ? 99999 : -99999, type_ch);
       } else {
-        sbuf_pos =
-            buf_append_printf(sbuf, sizeof(sbuf), sbuf_pos, "%-5d[%c] ", (int) (round(data[j] / 10.) * 10), type_ch);
+        sprintf(sbuf, "%s%-5d[%c] ", sbuf, (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/dfrobot_sen0395/commands.cpp

@@ -127,9 +127,7 @@ 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;
 
-    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;
+    this->cmd_ = str_sprintf("detRangeCfg -1 %.0f %.0f", min1 / 0.15, max1 / 0.15);
   } else if (min3 < 0 || max3 < 0) {
     this->min1_ = min1 = round(min1 / 0.15) * 0.15;
     this->max1_ = max1 = round(max1 / 0.15) * 0.15;
@@ -137,10 +135,7 @@ 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;
 
-    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;
+    this->cmd_ = str_sprintf("detRangeCfg -1 %.0f %.0f %.0f %.0f", min1 / 0.15, max1 / 0.15, min2 / 0.15, max2 / 0.15);
   } else if (min4 < 0 || max4 < 0) {
     this->min1_ = min1 = round(min1 / 0.15) * 0.15;
     this->max1_ = max1 = round(max1 / 0.15) * 0.15;
@@ -150,10 +145,9 @@ 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;
 
-    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;
+    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);
   } else {
     this->min1_ = min1 = round(min1 / 0.15) * 0.15;
     this->max1_ = max1 = round(max1 / 0.15) * 0.15;
@@ -164,10 +158,10 @@ 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;
 
-    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->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);
   }
 
   this->min1_ = min1;
@@ -209,10 +203,7 @@ 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);
-  // 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;
+  this->cmd_ = str_sprintf("setLatency %.03f %.03f", this->delay_after_detection_, this->delay_after_disappear_);
 };
 
 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];  // "sensorCfgStart " (15) + "0/1" (1) + null = 17
-    buf_append_printf(tmp_cmd, sizeof(tmp_cmd), 0, "sensorCfgStart %d", startup_mode);
+    char tmp_cmd[20] = {0};
+    sprintf(tmp_cmd, "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];  // "setSensitivity " (15) + "0-9" (1) + null = 17
-    buf_append_printf(tmp_cmd, sizeof(tmp_cmd), 0, "setSensitivity %d", sensitivity);
+    char tmp_cmd[20] = {0};
+    sprintf(tmp_cmd, "setSensitivity %d", sensitivity);
     cmd_ = std::string(tmp_cmd);
   };
   uint8_t on_message(std::string &message) override;

esphome/components/esp32/preferences.cpp

@@ -19,16 +19,7 @@ static constexpr size_t KEY_BUFFER_SIZE = 12;
 
 struct NVSData {
   uint32_t key;
-  std::unique_ptr<uint8_t[]> data;
-  size_t len;
-
-  void set_data(const uint8_t *src, size_t size) {
-    if (!this->data || this->len != size) {
-      this->data = std::make_unique<uint8_t[]>(size);
-      this->len = size;
-    }
-    memcpy(this->data.get(), src, size);
-  }
+  SmallInlineBuffer<8> data;  // Most prefs fit in 8 bytes (covers fan, cover, select, etc.)
 };
 
 static std::vector<NVSData> s_pending_save;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
@@ -41,14 +32,14 @@ class ESP32PreferenceBackend : public ESPPreferenceBackend {
     // try find in pending saves and update that
     for (auto &obj : s_pending_save) {
       if (obj.key == this->key) {
-        obj.set_data(data, len);
+        obj.data.set(data, len);
         return true;
       }
     }
     NVSData save{};
     save.key = this->key;
-    save.set_data(data, len);
-    s_pending_save.emplace_back(std::move(save));
+    save.data.set(data, len);
+    s_pending_save.push_back(std::move(save));
     ESP_LOGVV(TAG, "s_pending_save: key: %" PRIu32 ", len: %zu", this->key, len);
     return true;
   }
@@ -56,11 +47,11 @@ class ESP32PreferenceBackend : public ESPPreferenceBackend {
     // try find in pending saves and load from that
     for (auto &obj : s_pending_save) {
       if (obj.key == this->key) {
-        if (obj.len != len) {
+        if (obj.data.size() != len) {
           // size mismatch
           return false;
         }
-        memcpy(data, obj.data.get(), len);
+        memcpy(data, obj.data.data(), len);
         return true;
       }
     }
@@ -136,10 +127,10 @@ class ESP32Preferences : public ESPPreferences {
       snprintf(key_str, sizeof(key_str), "%" PRIu32, save.key);
       ESP_LOGVV(TAG, "Checking if NVS data %s has changed", key_str);
       if (this->is_changed_(this->nvs_handle, save, key_str)) {
-        esp_err_t err = nvs_set_blob(this->nvs_handle, key_str, save.data.get(), save.len);
-        ESP_LOGV(TAG, "sync: key: %s, len: %zu", key_str, save.len);
+        esp_err_t err = nvs_set_blob(this->nvs_handle, key_str, save.data.data(), save.data.size());
+        ESP_LOGV(TAG, "sync: key: %s, len: %zu", key_str, save.data.size());
         if (err != 0) {
-          ESP_LOGV(TAG, "nvs_set_blob('%s', len=%zu) failed: %s", key_str, save.len, esp_err_to_name(err));
+          ESP_LOGV(TAG, "nvs_set_blob('%s', len=%zu) failed: %s", key_str, save.data.size(), esp_err_to_name(err));
           failed++;
           last_err = err;
           last_key = save.key;
@@ -147,7 +138,7 @@ class ESP32Preferences : public ESPPreferences {
         }
         written++;
       } else {
-        ESP_LOGV(TAG, "NVS data not changed skipping %" PRIu32 "  len=%zu", save.key, save.len);
+        ESP_LOGV(TAG, "NVS data not changed skipping %" PRIu32 "  len=%zu", save.key, save.data.size());
         cached++;
       }
       s_pending_save.erase(s_pending_save.begin() + i);
@@ -178,7 +169,7 @@ class ESP32Preferences : public ESPPreferences {
       return true;
     }
     // Check size first before allocating memory
-    if (actual_len != to_save.len) {
+    if (actual_len != to_save.data.size()) {
       return true;
     }
     auto stored_data = std::make_unique<uint8_t[]>(actual_len);
@@ -187,7 +178,7 @@ class ESP32Preferences : public ESPPreferences {
       ESP_LOGV(TAG, "nvs_get_blob('%s') failed: %s", key_str, esp_err_to_name(err));
       return true;
     }
-    return memcmp(to_save.data.get(), stored_data.get(), to_save.len) != 0;
+    return memcmp(to_save.data.data(), stored_data.get(), to_save.data.size()) != 0;
   }
 
   bool reset() override {

esphome/components/esp32_hosted/update/esp32_hosted_update.cpp

@@ -69,10 +69,7 @@ void Esp32HostedUpdate::setup() {
   // Get coprocessor version
   esp_hosted_coprocessor_fwver_t ver_info;
   if (esp_hosted_get_coprocessor_fwversion(&ver_info) == ESP_OK) {
-    // 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;
+    this->update_info_.current_version = str_sprintf("%d.%d.%d", ver_info.major1, ver_info.minor1, ver_info.patch1);
   } else {
     this->update_info_.current_version = "unknown";
   }

esphome/components/esp8266/core.cpp

@@ -6,11 +6,7 @@
 #include "esphome/core/helpers.h"
 #include "preferences.h"
 #include <Arduino.h>
-#include <core_esp8266_features.h>
-
-extern "C" {
-#include <user_interface.h>
-}
+#include <Esp.h>
 
 namespace esphome {
 
@@ -20,19 +16,23 @@ 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() {
-  system_restart();
+  ESP.restart();  // NOLINT(readability-static-accessed-through-instance)
   // restart() doesn't always end execution
   while (true) {  // NOLINT(clang-diagnostic-unreachable-code)
     yield();
   }
 }
 void arch_init() {}
-void IRAM_ATTR HOT arch_feed_wdt() { system_soft_wdt_feed(); }
+void IRAM_ATTR HOT arch_feed_wdt() {
+  ESP.wdtFeed();  // NOLINT(readability-static-accessed-through-instance)
+}
 
 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_get_cycle_count(); }
+uint32_t IRAM_ATTR HOT arch_get_cpu_cycle_count() {
+  return ESP.getCycleCount();  // NOLINT(readability-static-accessed-through-instance)
+}
 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 buf_append_printf(buffer, len, 0, "GPIO%u", this->pin_);
+  return snprintf(buffer, len, "GPIO%u", this->pin_);
 }
 
 bool ESP8266GPIOPin::digital_read() {

esphome/components/event/__init__.py

@@ -90,7 +90,9 @@ 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.StringRef, "event_type")], conf)
+        await automation.build_automation(
+            trigger, [(cg.std_string, "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<StringRef> {
+class EventTrigger : public Trigger<std::string> {
  public:
   EventTrigger(Event *event) {
-    event->add_on_event_callback([this](StringRef event_type) { this->trigger(event_type); });
+    event->add_on_event_callback([this](const std::string &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(StringRef(found));
+  this->event_callback_.call(event_type);
 #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(StringRef event_type)> &&callback) {
+void Event::add_on_event_callback(std::function<void(const std::string &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(StringRef event_type)> &&callback);
+  void add_on_event_callback(std::function<void(const std::string &event_type)> &&callback);
 
  protected:
-  LazyCallbackManager<void(StringRef event_type)> event_callback_;
+  LazyCallbackManager<void(const std::string &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 char *command, EzoCommandType command_type, uint16_t delay_ms) {
+void EZOSensor::add_command_(const std::string &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;
@@ -169,17 +169,13 @@ void EZOSensor::add_command_(const char *command, EzoCommandType command_type, u
 }
 
 void EZOSensor::set_calibration_point_(EzoCalibrationType type, float 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);
+  std::string payload = str_sprintf("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) {
-    // max 8: "I2C,"(4) + uint8(3) + null
-    char payload[8];
-    snprintf(payload, sizeof(payload), "I2C,%u", address);
+    std::string payload = str_sprintf("I2C,%u", address);
     this->new_address_ = address;
     this->add_command_(payload, EzoCommandType::EZO_I2C);
   } else {
@@ -198,9 +194,7 @@ 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) {
-  // 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);
+  std::string payload = str_sprintf("T,%0.2f", value);
   this->add_command_(payload, EzoCommandType::EZO_T);
 }
 
@@ -221,9 +215,7 @@ void EZOSensor::set_calibration_point_high(float value) {
 }
 
 void EZOSensor::set_calibration_generic(float 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);
+  std::string payload = str_sprintf("Cal,%0.2f", value);
   this->add_command_(payload, EzoCommandType::EZO_CALIBRATION, 900);
 }
 
@@ -231,11 +223,13 @@ 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) { 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.c_str(), EzoCommandType::EZO_CUSTOM);
+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::send_custom(const std::string &to_send) { this->add_command_(to_send, 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 char *command, EzoCommandType command_type, uint16_t delay_ms = 300);
+  void add_command_(const std::string &command, EzoCommandType command_type, uint16_t delay_ms = 300);
 
   void set_calibration_point_(EzoCalibrationType type, float value);
 

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.StringRef)
+    "FanPresetSetTrigger", automation.Trigger.template(cg.std_string)
 )
 
 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.StringRef, "x")], conf)
+        await automation.build_automation(trigger, [(cg.std_string, "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<StringRef> {
+class FanPresetSetTrigger : public Trigger<std::string> {
  public:
   FanPresetSetTrigger(Fan *state) {
     state->add_on_state_callback([this, state]() {
@@ -216,7 +216,7 @@ class FanPresetSetTrigger : public Trigger<StringRef> {
       auto should_trigger = preset_mode != this->last_preset_mode_;
       this->last_preset_mode_ = preset_mode;
       if (should_trigger) {
-        this->trigger(preset_mode);
+        this->trigger(std::string(preset_mode));
       }
     });
     this->last_preset_mode_ = state->get_preset_mode();

esphome/components/gdk101/gdk101.cpp

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

esphome/components/hmac_sha256/hmac_sha256.cpp

@@ -1,3 +1,4 @@
+#include <cstdio>
 #include <cstring>
 #include "hmac_sha256.h"
 #if defined(USE_ESP32) || defined(USE_ESP8266) || defined(USE_RP2040) || defined(USE_LIBRETINY) || defined(USE_HOST)
@@ -25,7 +26,9 @@ void HmacSHA256::calculate() { mbedtls_md_hmac_finish(&this->ctx_, this->digest_
 void HmacSHA256::get_bytes(uint8_t *output) { memcpy(output, this->digest_, SHA256_DIGEST_SIZE); }
 
 void HmacSHA256::get_hex(char *output) {
-  format_hex_to(output, SHA256_DIGEST_SIZE * 2 + 1, this->digest_, SHA256_DIGEST_SIZE);
+  for (size_t i = 0; i < SHA256_DIGEST_SIZE; i++) {
+    sprintf(output + (i * 2), "%02x", this->digest_[i]);
+  }
 }
 
 bool HmacSHA256::equals_bytes(const uint8_t *expected) {

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];
-  buf_append_printf(value_buf, sizeof(value_buf), 0, "%g", value);
+  snprintf(value_buf, sizeof(value_buf), "%g", value);
   entity_value.value = StringRef(value_buf);
 
   api::global_api_server->send_homeassistant_action(resp);

esphome/components/http_request/http_request.h

@@ -242,7 +242,9 @@ template<typename... Ts> class HttpRequestSendAction : public Action<Ts...> {
       return;
     }
 
-    size_t max_length = this->max_response_buffer_size_;
+    size_t content_length = container->content_length;
+    size_t max_length = std::min(content_length, this->max_response_buffer_size_);
+
 #ifdef USE_HTTP_REQUEST_RESPONSE
     if (this->capture_response_.value(x...)) {
       std::string response_body;

esphome/components/http_request/http_request_idf.cpp

@@ -213,12 +213,18 @@ int HttpContainerIDF::read(uint8_t *buf, size_t max_len) {
   const uint32_t start = millis();
   watchdog::WatchdogManager wdm(this->parent_->get_watchdog_timeout());
 
-  this->feed_wdt();
-  int read_len = esp_http_client_read(this->client_, (char *) buf, max_len);
-  this->feed_wdt();
-  if (read_len > 0) {
-    this->bytes_read_ += read_len;
+  int bufsize = std::min(max_len, this->content_length - this->bytes_read_);
+
+  if (bufsize == 0) {
+    this->duration_ms += (millis() - start);
+    return 0;
   }
+
+  this->feed_wdt();
+  int read_len = esp_http_client_read(this->client_, (char *) buf, bufsize);
+  this->feed_wdt();
+  this->bytes_read_ += read_len;
+
   this->duration_ms += (millis() - start);
 
   return read_len;

esphome/components/hub75/display.py

@@ -1,4 +1,3 @@
-import logging
 from typing import Any
 
 from esphome import automation, pins
@@ -19,16 +18,13 @@ from esphome.const import (
     CONF_ROTATION,
     CONF_UPDATE_INTERVAL,
 )
-from esphome.core import ID, EnumValue
+from esphome.core import ID
 from esphome.cpp_generator import MockObj, TemplateArgsType
 import esphome.final_validate as fv
-from esphome.helpers import add_class_to_obj
 from esphome.types import ConfigType
 
 from . import boards, hub75_ns
 
-_LOGGER = logging.getLogger(__name__)
-
 DEPENDENCIES = ["esp32"]
 CODEOWNERS = ["@stuartparmenter"]
 
@@ -124,51 +120,13 @@ PANEL_LAYOUTS = {
 }
 
 Hub75ScanWiring = cg.global_ns.enum("Hub75ScanWiring", is_class=True)
-SCAN_WIRINGS = {
+SCAN_PATTERNS = {
     "STANDARD_TWO_SCAN": Hub75ScanWiring.STANDARD_TWO_SCAN,
-    "SCAN_1_4_16PX_HIGH": Hub75ScanWiring.SCAN_1_4_16PX_HIGH,
-    "SCAN_1_8_32PX_HIGH": Hub75ScanWiring.SCAN_1_8_32PX_HIGH,
-    "SCAN_1_8_40PX_HIGH": Hub75ScanWiring.SCAN_1_8_40PX_HIGH,
-    "SCAN_1_8_64PX_HIGH": Hub75ScanWiring.SCAN_1_8_64PX_HIGH,
+    "FOUR_SCAN_16PX_HIGH": Hub75ScanWiring.FOUR_SCAN_16PX_HIGH,
+    "FOUR_SCAN_32PX_HIGH": Hub75ScanWiring.FOUR_SCAN_32PX_HIGH,
+    "FOUR_SCAN_64PX_HIGH": Hub75ScanWiring.FOUR_SCAN_64PX_HIGH,
 }
 
-# Deprecated scan wiring names - mapped to new names
-DEPRECATED_SCAN_WIRINGS = {
-    "FOUR_SCAN_16PX_HIGH": "SCAN_1_4_16PX_HIGH",
-    "FOUR_SCAN_32PX_HIGH": "SCAN_1_8_32PX_HIGH",
-    "FOUR_SCAN_64PX_HIGH": "SCAN_1_8_64PX_HIGH",
-}
-
-
-def _validate_scan_wiring(value):
-    """Validate scan_wiring with deprecation warnings for old names."""
-    value = cv.string(value).upper().replace(" ", "_")
-
-    # Check if using deprecated name
-    # Remove deprecated names in 2026.7.0
-    if value in DEPRECATED_SCAN_WIRINGS:
-        new_name = DEPRECATED_SCAN_WIRINGS[value]
-        _LOGGER.warning(
-            "Scan wiring '%s' is deprecated and will be removed in ESPHome 2026.7.0. "
-            "Please use '%s' instead.",
-            value,
-            new_name,
-        )
-        value = new_name
-
-    # Validate against allowed values
-    if value not in SCAN_WIRINGS:
-        raise cv.Invalid(
-            f"Unknown scan wiring '{value}'. "
-            f"Valid options are: {', '.join(sorted(SCAN_WIRINGS.keys()))}"
-        )
-
-    # Return as EnumValue like cv.enum does
-    result = add_class_to_obj(value, EnumValue)
-    result.enum_value = SCAN_WIRINGS[value]
-    return result
-
-
 Hub75ClockSpeed = cg.global_ns.enum("Hub75ClockSpeed", is_class=True)
 CLOCK_SPEEDS = {
     "8MHZ": Hub75ClockSpeed.HZ_8M,
@@ -424,7 +382,9 @@ CONFIG_SCHEMA = cv.All(
             cv.Optional(CONF_LAYOUT_COLS): cv.positive_int,
             cv.Optional(CONF_LAYOUT): cv.enum(PANEL_LAYOUTS, upper=True, space="_"),
             # Panel hardware configuration
-            cv.Optional(CONF_SCAN_WIRING): _validate_scan_wiring,
+            cv.Optional(CONF_SCAN_WIRING): cv.enum(
+                SCAN_PATTERNS, upper=True, space="_"
+            ),
             cv.Optional(CONF_SHIFT_DRIVER): cv.enum(SHIFT_DRIVERS, upper=True),
             # Display configuration
             cv.Optional(CONF_DOUBLE_BUFFER): cv.boolean,
@@ -587,7 +547,7 @@ def _build_config_struct(
 async def to_code(config: ConfigType) -> None:
     add_idf_component(
         name="esphome/esp-hub75",
-        ref="0.3.0",
+        ref="0.2.2",
     )
 
     # Set compile-time configuration via build flags (so external library sees them)

esphome/components/i2c/i2c.cpp

@@ -42,8 +42,8 @@ ErrorCode I2CDevice::read_register16(uint16_t a_register, uint8_t *data, size_t
 }
 
 ErrorCode I2CDevice::write_register(uint8_t a_register, const uint8_t *data, size_t len) const {
-  SmallBufferWithHeapFallback<17> buffer_alloc(len + 1);  // Most I2C writes are <= 16 bytes
-  uint8_t *buffer = buffer_alloc.get();
+  SmallBufferWithHeapFallback<17> buffer_alloc;  // Most I2C writes are <= 16 bytes
+  uint8_t *buffer = buffer_alloc.get(len + 1);
 
   buffer[0] = a_register;
   std::copy(data, data + len, buffer + 1);
@@ -51,8 +51,8 @@ ErrorCode I2CDevice::write_register(uint8_t a_register, const uint8_t *data, siz
 }
 
 ErrorCode I2CDevice::write_register16(uint16_t a_register, const uint8_t *data, size_t len) const {
-  SmallBufferWithHeapFallback<18> buffer_alloc(len + 2);  // Most I2C writes are <= 16 bytes + 2 for register
-  uint8_t *buffer = buffer_alloc.get();
+  SmallBufferWithHeapFallback<18> buffer_alloc;  // Most I2C writes are <= 16 bytes + 2 for register
+  uint8_t *buffer = buffer_alloc.get(len + 2);
 
   buffer[0] = a_register >> 8;
   buffer[1] = a_register;

esphome/components/i2c/i2c_bus.h

@@ -11,6 +11,22 @@
 namespace esphome {
 namespace i2c {
 
+/// @brief Helper class for efficient buffer allocation - uses stack for small sizes, heap for large
+template<size_t STACK_SIZE> class SmallBufferWithHeapFallback {
+ public:
+  uint8_t *get(size_t size) {
+    if (size <= STACK_SIZE) {
+      return this->stack_buffer_;
+    }
+    this->heap_buffer_ = std::unique_ptr<uint8_t[]>(new uint8_t[size]);
+    return this->heap_buffer_.get();
+  }
+
+ private:
+  uint8_t stack_buffer_[STACK_SIZE];
+  std::unique_ptr<uint8_t[]> heap_buffer_;
+};
+
 /// @brief Error codes returned by I2CBus and I2CDevice methods
 enum ErrorCode {
   NO_ERROR = 0,                ///< No error found during execution of method
@@ -76,8 +92,8 @@ class I2CBus {
       total_len += read_buffers[i].len;
     }
 
-    SmallBufferWithHeapFallback<128> buffer_alloc(total_len);  // Most I2C reads are small
-    uint8_t *buffer = buffer_alloc.get();
+    SmallBufferWithHeapFallback<128> buffer_alloc;  // Most I2C reads are small
+    uint8_t *buffer = buffer_alloc.get(total_len);
 
     auto err = this->write_readv(address, nullptr, 0, buffer, total_len);
     if (err != ERROR_OK)
@@ -100,8 +116,8 @@ class I2CBus {
       total_len += write_buffers[i].len;
     }
 
-    SmallBufferWithHeapFallback<128> buffer_alloc(total_len);  // Most I2C writes are small
-    uint8_t *buffer = buffer_alloc.get();
+    SmallBufferWithHeapFallback<128> buffer_alloc;  // Most I2C writes are small
+    uint8_t *buffer = buffer_alloc.get(total_len);
 
     size_t pos = 0;
     for (size_t i = 0; i != count; i++) {

esphome/components/infrared/infrared.cpp

@@ -19,12 +19,12 @@ 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;
-  this->base64url_ptr_ = nullptr;
+  this->base85_ptr_ = nullptr;
   return *this;
 }
 
-InfraredCall &InfraredCall::set_raw_timings_base64url(const std::string &base64url) {
-  this->base64url_ptr_ = &base64url;
+InfraredCall &InfraredCall::set_raw_timings_base85(const std::string &base85) {
+  this->base85_ptr_ = &base85;
   this->raw_timings_ = nullptr;
   this->packed_data_ = nullptr;
   return *this;
@@ -35,7 +35,7 @@ InfraredCall &InfraredCall::set_raw_timings_packed(const uint8_t *data, uint16_t
   this->packed_length_ = length;
   this->packed_count_ = count;
   this->raw_timings_ = nullptr;
-  this->base64url_ptr_ = nullptr;
+  this->base85_ptr_ = nullptr;
   return *this;
 }
 
@@ -101,22 +101,13 @@ 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");
+  } else if (call.is_base85()) {
+    // Decode base85 directly into transmit buffer (zero heap allocations)
+    if (!transmit_data->set_data_from_base85(call.get_base85_data())) {
+      ESP_LOGE(TAG, "Invalid base85 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(),
+    ESP_LOGD(TAG, "Transmitting base85 raw timings: count=%zu, repeat=%u", transmit_data->get_data().size(),
              call.get_repeat_count());
   } else {
     // From vector (lambdas/automations)

esphome/components/infrared/infrared.h

@@ -40,11 +40,11 @@ class InfraredCall {
   /// @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 base64url-encoded little-endian int32 data
+  /// Set the raw timings from base85-encoded 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 Usage: For web_server where the encoded string is on the stack.
   /// @note Decoding happens at perform() time, directly into the transmit buffer.
-  InfraredCall &set_raw_timings_base64url(const std::string &base64url);
+  InfraredCall &set_raw_timings_base85(const std::string &base85);
 
   /// 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().
@@ -59,18 +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)
+  /// Get the raw timings (only valid if set via set_raw_timings, not packed or base85)
   const std::vector<int32_t> &get_raw_timings() const { return *this->raw_timings_; }
-  /// Check if raw timings have been set (any format)
+  /// Check if raw timings have been set (vector, packed, or base85)
   bool has_raw_timings() const {
-    return this->raw_timings_ != nullptr || this->packed_data_ != nullptr || this->base64url_ptr_ != nullptr;
+    return this->raw_timings_ != nullptr || this->packed_data_ != nullptr || this->base85_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_; }
+  /// Check if using base85 data format
+  bool is_base85() const { return this->base85_ptr_ != nullptr; }
+  /// Get the base85 data string
+  const std::string &get_base85_data() const { return *this->base85_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_; }
@@ -84,8 +84,8 @@ class InfraredCall {
   optional<uint32_t> carrier_frequency_;
   // Pointer to vector-based timings (caller-owned, must outlive perform())
   const std::vector<int32_t> *raw_timings_{nullptr};
-  // Pointer to base64url-encoded string (caller-owned, must outlive perform())
-  const std::string *base64url_ptr_{nullptr};
+  // Pointer to base85-encoded string (caller-owned, must outlive perform())
+  const std::string *base85_ptr_{nullptr};
   // Pointer to packed protobuf buffer (caller-owned, must outlive perform())
   const uint8_t *packed_data_{nullptr};
   uint16_t packed_length_{0};

esphome/components/libretiny/preferences.cpp

@@ -18,16 +18,7 @@ static constexpr size_t KEY_BUFFER_SIZE = 12;
 
 struct NVSData {
   uint32_t key;
-  std::unique_ptr<uint8_t[]> data;
-  size_t len;
-
-  void set_data(const uint8_t *src, size_t size) {
-    if (!this->data || this->len != size) {
-      this->data = std::make_unique<uint8_t[]>(size);
-      this->len = size;
-    }
-    memcpy(this->data.get(), src, size);
-  }
+  SmallInlineBuffer<8> data;  // Most prefs fit in 8 bytes (covers fan, cover, select, etc.)
 };
 
 static std::vector<NVSData> s_pending_save;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
@@ -42,14 +33,14 @@ class LibreTinyPreferenceBackend : public ESPPreferenceBackend {
     // try find in pending saves and update that
     for (auto &obj : s_pending_save) {
       if (obj.key == this->key) {
-        obj.set_data(data, len);
+        obj.data.set(data, len);
         return true;
       }
     }
     NVSData save{};
     save.key = this->key;
-    save.set_data(data, len);
-    s_pending_save.emplace_back(std::move(save));
+    save.data.set(data, len);
+    s_pending_save.push_back(std::move(save));
     ESP_LOGVV(TAG, "s_pending_save: key: %" PRIu32 ", len: %zu", this->key, len);
     return true;
   }
@@ -58,11 +49,11 @@ class LibreTinyPreferenceBackend : public ESPPreferenceBackend {
     // try find in pending saves and load from that
     for (auto &obj : s_pending_save) {
       if (obj.key == this->key) {
-        if (obj.len != len) {
+        if (obj.data.size() != len) {
           // size mismatch
           return false;
         }
-        memcpy(data, obj.data.get(), len);
+        memcpy(data, obj.data.data(), len);
         return true;
       }
     }
@@ -126,11 +117,11 @@ class LibreTinyPreferences : public ESPPreferences {
       snprintf(key_str, sizeof(key_str), "%" PRIu32, save.key);
       ESP_LOGVV(TAG, "Checking if FDB data %s has changed", key_str);
       if (this->is_changed_(&this->db, save, key_str)) {
-        ESP_LOGV(TAG, "sync: key: %s, len: %zu", key_str, save.len);
-        fdb_blob_make(&this->blob, save.data.get(), save.len);
+        ESP_LOGV(TAG, "sync: key: %s, len: %zu", key_str, save.data.size());
+        fdb_blob_make(&this->blob, save.data.data(), save.data.size());
         fdb_err_t err = fdb_kv_set_blob(&this->db, key_str, &this->blob);
         if (err != FDB_NO_ERR) {
-          ESP_LOGV(TAG, "fdb_kv_set_blob('%s', len=%zu) failed: %d", key_str, save.len, err);
+          ESP_LOGV(TAG, "fdb_kv_set_blob('%s', len=%zu) failed: %d", key_str, save.data.size(), err);
           failed++;
           last_err = err;
           last_key = save.key;
@@ -138,7 +129,7 @@ class LibreTinyPreferences : public ESPPreferences {
         }
         written++;
       } else {
-        ESP_LOGD(TAG, "FDB data not changed; skipping %" PRIu32 "  len=%zu", save.key, save.len);
+        ESP_LOGD(TAG, "FDB data not changed; skipping %" PRIu32 "  len=%zu", save.key, save.data.size());
         cached++;
       }
       s_pending_save.erase(s_pending_save.begin() + i);
@@ -162,7 +153,7 @@ class LibreTinyPreferences : public ESPPreferences {
     }
 
     // Check size first - if different, data has changed
-    if (kv.value_len != to_save.len) {
+    if (kv.value_len != to_save.data.size()) {
       return true;
     }
 
@@ -176,7 +167,7 @@ class LibreTinyPreferences : public ESPPreferences {
     }
 
     // Compare the actual data
-    return memcmp(to_save.data.get(), stored_data.get(), kv.value_len) != 0;
+    return memcmp(to_save.data.data(), stored_data.get(), kv.value_len) != 0;
   }
 
   bool reset() override {

esphome/components/light/light_json_schema.cpp

@@ -1,5 +1,4 @@
 #include "light_json_schema.h"
-#include "color_mode.h"
 #include "light_output.h"
 #include "esphome/core/progmem.h"
 
@@ -9,32 +8,29 @@ 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.
-// 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;
+// 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];
   }
+  return nullptr;
 }
 
 void LightJSONSchema::dump_json(LightState &state, JsonObject root) {
@@ -48,7 +44,7 @@ void LightJSONSchema::dump_json(LightState &state, JsonObject root) {
   auto values = state.remote_values;
 
   const auto color_mode = values.get_color_mode();
-  const auto *mode_str = get_color_mode_json_str(color_mode);
+  const char *mode_str = get_color_mode_json_str(color_mode);
   if (mode_str != nullptr) {
     root[ESPHOME_F("color_mode")] = mode_str;
   }

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 buf_append_printf(buffer, len, 0, "%u via Max6956", this->pin_);
+  return snprintf(buffer, len, "%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 buf_append_printf(buffer, len, 0, "%u via MCP23016", this->pin_);
+  return snprintf(buffer, len, "%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 buf_append_printf(buffer, len, 0, "%u via MCP23XXX", this->pin_);
+  return snprintf(buffer, len, "%u via MCP23XXX", this->pin_);
 }
 
 template class MCP23XXXGPIOPin<8>;

esphome/components/mipi_dsi/models/guition.py

@@ -101,225 +101,4 @@ 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

@@ -224,9 +224,12 @@ 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());
-    log_pin(TAG, "  CS Pin: ", this->cs_);
-    log_pin(TAG, "  Reset Pin: ", this->reset_pin_);
-    log_pin(TAG, "  DC Pin: ", this->dc_pin_);
+    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());
     esph_log_config(TAG,
                     "  SPI Mode: %d\n"
                     "  SPI Data rate: %dMHz\n"

esphome/components/mipi_spi/models/adafruit.py

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

esphome/components/mipi_spi/models/amoled.py

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

esphome/components/mipi_spi/models/cyd.py

@@ -1,45 +1,10 @@
-from .ili import ILI9341, ILI9342, ST7789V
+from .ili import ILI9341
 
 ILI9341.extend(
-    # ESP32-2432S028 CYD board with Micro USB, has ILI9341 controller
     "ESP32-2432S028",
     data_rate="40MHz",
-    cs_pin={"number": 15, "ignore_strapping_warning": True},
-    dc_pin={"number": 2, "ignore_strapping_warning": True},
+    cs_pin=15,
+    dc_pin=2,
 )
 
-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
-    )
-)
+models = {}

esphome/components/mipi_spi/models/ili.py

@@ -148,34 +148,6 @@ 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",
@@ -786,3 +758,5 @@ ST7796.extend(
     dc_pin=0,
     invert_colors=True,
 )
+
+models = {}

esphome/components/mipi_spi/models/jc.py

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

esphome/components/mipi_spi/models/lanbon.py

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

esphome/components/mipi_spi/models/lilygo.py

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

esphome/components/modbus_controller/modbus_controller.h

@@ -271,31 +271,24 @@ 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:
-        buf_append_printf(buf, sizeof(buf), 0, "%" PRIu64, static_cast<uint64_t>(value));
-        return buf;
+        return std::to_string(static_cast<uint64_t>(value));
       case SensorValueType::S_WORD:
       case SensorValueType::S_DWORD:
       case SensorValueType::S_DWORD_R:
       case SensorValueType::S_QWORD:
       case SensorValueType::S_QWORD_R:
-        buf_append_printf(buf, sizeof(buf), 0, "%" PRId64, value);
-        return buf;
+        return std::to_string(value);
       case SensorValueType::FP32_R:
       case SensorValueType::FP32:
-        buf_append_printf(buf, sizeof(buf), 0, "%.1f", bit_cast<float>(static_cast<uint32_t>(value)));
-        return buf;
+        return str_sprintf("%.1f", bit_cast<float>(static_cast<uint32_t>(value)));
       default:
-        buf_append_printf(buf, sizeof(buf), 0, "%" PRId64, value);
-        return buf;
+        return std::to_string(value);
     }
   }
 

esphome/components/modbus_controller/text_sensor/modbus_textsensor.cpp

@@ -16,20 +16,12 @@ 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: {
-        // max 3: 2 hex digits + null
-        char hex_buf[3];
-        snprintf(hex_buf, sizeof(hex_buf), "%02x", b);
-        output_str += hex_buf;
+      case RawEncoding::HEXBYTES:
+        output_str += str_snprintf("%02x", 2, b);
         break;
-      }
-      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;
+      case RawEncoding::COMMA:
+        output_str += str_sprintf(index != this->offset ? ",%d" : "%d", b);
         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 buf_append_printf(buffer, len, 0, "ELE%u on MPR121", this->pin_);
+  return snprintf(buffer, len, "ELE%u on MPR121", this->pin_);
 }
 
 }  // namespace mpr121

esphome/components/mqtt/mqtt_client.cpp

@@ -5,7 +5,6 @@
 #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"
@@ -67,13 +66,10 @@ void MQTTClientComponent::setup() {
         "esphome/discover", [this](const std::string &topic, const std::string &payload) { this->send_device_info_(); },
         2);
 
-    // 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());
+    std::string topic = "esphome/ping/";
+    topic.append(App.get_name());
     this->subscribe(
-        ping_topic, [this](const std::string &topic, const std::string &payload) { this->send_device_info_(); }, 2);
+        topic, [this](const std::string &topic, const std::string &payload) { this->send_device_info_(); }, 2);
   }
 
   if (this->enable_on_boot_) {
@@ -85,11 +81,8 @@ void MQTTClientComponent::send_device_info_() {
   if (!this->is_connected() or !this->is_discovery_ip_enabled()) {
     return;
   }
-  // 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());
+  std::string topic = "esphome/discover/";
+  topic.append(App.get_name());
 
   // NOLINTBEGIN(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
   this->publish_json(
@@ -507,49 +500,39 @@ 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 this->publish(topic.c_str(), payload, payload_length, qos, retain);
+  return publish({.topic = topic, .payload = std::string(payload, payload_length), .qos = qos, .retain = 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;
   }
-  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);
+  bool logging_topic = this->log_message_.topic == message.topic;
+  bool ret = this->mqtt_backend_.publish(message);
   delay(0);
   if (!ret && !logging_topic && this->is_connected()) {
     delay(0);
-    ret = this->mqtt_backend_.publish(topic, payload, payload_length, qos, retain);
+    ret = this->mqtt_backend_.publish(message);
     delay(0);
   }
 
   if (!logging_topic) {
     if (ret) {
-      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);
+      ESP_LOGV(TAG, "Publish(topic='%s' payload='%s' retain=%d qos=%d)", message.topic.c_str(), message.payload.c_str(),
+               message.retain, message.qos);
     } else {
-      ESP_LOGV(TAG, "Publish failed for topic='%s' (len=%u). Will retry", topic, payload_length);
+      ESP_LOGV(TAG, "Publish failed for topic='%s' (len=%u). Will retry", message.topic.c_str(),
+               message.payload.length());
       this->status_momentary_warning("publish", 1000);
     }
   }
   return ret != 0;
 }
-
-bool MQTTClientComponent::publish_json(const char *topic, const json::json_build_t &f, uint8_t qos, bool retain) {
+bool MQTTClientComponent::publish_json(const std::string &topic, const json::json_build_t &f, uint8_t qos,
+                                       bool retain) {
   std::string message = json::build_json(f);
-  return this->publish(topic, message.c_str(), message.length(), qos, retain);
+  return this->publish(topic, message, qos, retain);
 }
 
 void MQTTClientComponent::enable() {
@@ -652,8 +635,7 @@ 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)) {
-    char buf[ESPHOME_DEVICE_NAME_MAX_LEN + 1];
-    this->topic_prefix_ = str_sanitize_to(buf, App.get_name().c_str());
+    this->topic_prefix_ = str_sanitize(App.get_name());
   } else {
     this->topic_prefix_ = topic_prefix;
   }

esphome/components/mqtt/mqtt_client.h

@@ -229,9 +229,6 @@ class MQTTClientComponent : public Component
   bool publish(const std::string &topic, const char *payload, size_t payload_length, uint8_t qos = 0,
                bool retain = false);
 
-  /// Publish directly without creating MQTTMessage (avoids heap allocation for topic)
-  bool publish(const char *topic, const char *payload, size_t payload_length, uint8_t qos = 0, bool retain = false);
-
   /** Construct and send a JSON MQTT message.
    *
    * @param topic The topic.
@@ -240,9 +237,6 @@ class MQTTClientComponent : public Component
    */
   bool publish_json(const std::string &topic, const json::json_build_t &f, uint8_t qos = 0, bool retain = false);
 
-  /// Publish JSON directly without heap allocation for topic
-  bool publish_json(const char *topic, const json::json_build_t &f, uint8_t qos = 0, bool retain = false);
-
   /// Setup the MQTT client, registering a bunch of callbacks and attempting to connect.
   void setup() override;
   void dump_config() override;

esphome/components/mqtt/mqtt_component.cpp

@@ -48,8 +48,7 @@ void MQTTComponent::set_subscribe_qos(uint8_t qos) { this->subscribe_qos_ = qos;
 void MQTTComponent::set_retain(bool retain) { this->retain_ = retain; }
 
 std::string MQTTComponent::get_discovery_topic_(const MQTTDiscoveryInfo &discovery_info) const {
-  char sanitized_name[ESPHOME_DEVICE_NAME_MAX_LEN + 1];
-  str_sanitize_to(sanitized_name, App.get_name().c_str());
+  std::string sanitized_name = str_sanitize(App.get_name());
   const char *comp_type = this->component_type();
   char object_id_buf[OBJECT_ID_MAX_LEN];
   StringRef object_id = this->get_default_object_id_to_(object_id_buf);
@@ -61,7 +60,7 @@ std::string MQTTComponent::get_discovery_topic_(const MQTTDiscoveryInfo &discove
   p = append_char(p, '/');
   p = append_str(p, comp_type, strlen(comp_type));
   p = append_char(p, '/');
-  p = append_str(p, sanitized_name, strlen(sanitized_name));
+  p = append_str(p, sanitized_name.data(), sanitized_name.size());
   p = append_char(p, '/');
   p = append_str(p, object_id.c_str(), object_id.size());
   p = append_str(p, "/config", 7);
@@ -190,7 +189,8 @@ bool MQTTComponent::send_discovery_() {
         StringRef object_id = this->get_default_object_id_to_(object_id_buf);
         if (discovery_info.unique_id_generator == MQTT_MAC_ADDRESS_UNIQUE_ID_GENERATOR) {
           char friendly_name_hash[9];
-          snprintf(friendly_name_hash, sizeof(friendly_name_hash), "%08" PRIx32, fnv1_hash(this->friendly_name_()));
+          sprintf(friendly_name_hash, "%08" PRIx32, fnv1_hash(this->friendly_name_()));
+          friendly_name_hash[8] = 0;  // ensure the hash-string ends with null
           // Format: mac-component_type-hash (e.g. "aabbccddeeff-sensor-12345678")
           // MAC (12) + "-" (1) + domain (max 20) + "-" (1) + hash (8) + null (1) = 43
           char unique_id[MAC_ADDRESS_BUFFER_SIZE + ESPHOME_DOMAIN_MAX_LEN + 11];

esphome/components/network/ip_address.h

@@ -43,14 +43,6 @@ namespace network {
 /// Buffer size for IP address string (IPv6 max: 39 chars + null)
 static constexpr size_t IP_ADDRESS_BUFFER_SIZE = 40;
 
-/// Lowercase hex digits in IP address string (A-F -> a-f for IPv6 per RFC 5952)
-inline void lowercase_ip_str(char *buf) {
-  for (char *p = buf; *p; ++p) {
-    if (*p >= 'A' && *p <= 'F')
-      *p += 32;
-  }
-}
-
 struct IPAddress {
  public:
 #ifdef USE_HOST
@@ -60,15 +52,10 @@ struct IPAddress {
   }
   IPAddress(const std::string &in_address) { inet_aton(in_address.c_str(), &ip_addr_); }
   IPAddress(const ip_addr_t *other_ip) { ip_addr_ = *other_ip; }
-  std::string str() const {
-    char buf[IP_ADDRESS_BUFFER_SIZE];
-    this->str_to(buf);
-    return buf;
-  }
+  std::string str() const { return str_lower_case(inet_ntoa(ip_addr_)); }
   /// Write IP address to buffer. Buffer must be at least IP_ADDRESS_BUFFER_SIZE bytes.
   char *str_to(char *buf) const {
-    inet_ntop(AF_INET, &ip_addr_, buf, IP_ADDRESS_BUFFER_SIZE);
-    return buf;  // IPv4 only, no hex letters to lowercase
+    return const_cast<char *>(inet_ntop(AF_INET, &ip_addr_, buf, IP_ADDRESS_BUFFER_SIZE));
   }
 #else
   IPAddress() { ip_addr_set_zero(&ip_addr_); }
@@ -147,18 +134,9 @@ struct IPAddress {
   bool is_ip4() const { return IP_IS_V4(&ip_addr_); }
   bool is_ip6() const { return IP_IS_V6(&ip_addr_); }
   bool is_multicast() const { return ip_addr_ismulticast(&ip_addr_); }
-  std::string str() const {
-    char buf[IP_ADDRESS_BUFFER_SIZE];
-    this->str_to(buf);
-    return buf;
-  }
+  std::string str() const { return str_lower_case(ipaddr_ntoa(&ip_addr_)); }
   /// Write IP address to buffer. Buffer must be at least IP_ADDRESS_BUFFER_SIZE bytes.
-  /// Output is lowercased per RFC 5952 (IPv6 hex digits a-f).
-  char *str_to(char *buf) const {
-    ipaddr_ntoa_r(&ip_addr_, buf, IP_ADDRESS_BUFFER_SIZE);
-    lowercase_ip_str(buf);
-    return buf;
-  }
+  char *str_to(char *buf) const { return ipaddr_ntoa_r(&ip_addr_, buf, IP_ADDRESS_BUFFER_SIZE); }
   bool operator==(const IPAddress &other) const { return ip_addr_cmp(&ip_addr_, &other.ip_addr_); }
   bool operator!=(const IPAddress &other) const { return !ip_addr_cmp(&ip_addr_, &other.ip_addr_); }
   IPAddress &operator+=(uint8_t increase) {

esphome/components/nextion/nextion.cpp

@@ -1,7 +1,6 @@
 #include "nextion.h"
 #include <cinttypes>
 #include "esphome/core/application.h"
-#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include "esphome/core/util.h"
 
@@ -1284,9 +1283,8 @@ void Nextion::check_pending_waveform_() {
   size_t buffer_to_send = component->get_wave_buffer_size() < 255 ? component->get_wave_buffer_size()
                                                                   : 255;  // ADDT command can only send 255
 
-  char command[24];  // "addt " + uint8 + "," + uint8 + "," + uint8 + null = max 17 chars
-  buf_append_printf(command, sizeof(command), 0, "addt %u,%u,%zu", component->get_component_id(),
-                    component->get_wave_channel_id(), buffer_to_send);
+  std::string command = "addt " + to_string(component->get_component_id()) + "," +
+                        to_string(component->get_wave_channel_id()) + "," + to_string(buffer_to_send);
   if (!this->send_command_(command)) {
     delete nb;  // NOLINT(cppcoreguidelines-owning-memory)
     this->waveform_queue_.pop_front();

esphome/components/nextion/nextion_upload_arduino.cpp

@@ -34,7 +34,7 @@ int Nextion::upload_by_chunks_(HTTPClient &http_client, uint32_t &range_start) {
   }
 
   char range_header[32];
-  buf_append_printf(range_header, sizeof(range_header), 0, "bytes=%" PRIu32 "-%" PRIu32, range_start, range_end);
+  sprintf(range_header, "bytes=%" PRIu32 "-%" PRIu32, range_start, range_end);
   ESP_LOGV(TAG, "Range: %s", range_header);
   http_client.addHeader("Range", range_header);
   int code = http_client.GET();

esphome/components/nextion/nextion_upload_esp32.cpp

@@ -36,7 +36,7 @@ int Nextion::upload_by_chunks_(esp_http_client_handle_t http_client, uint32_t &r
   }
 
   char range_header[32];
-  buf_append_printf(range_header, sizeof(range_header), 0, "bytes=%" PRIu32 "-%" PRIu32, range_start, range_end);
+  sprintf(range_header, "bytes=%" PRIu32 "-%" PRIu32, range_start, range_end);
   ESP_LOGV(TAG, "Range: %s", range_header);
   esp_http_client_set_header(http_client, "Range", range_header);
   ESP_LOGV(TAG, "Open HTTP");

esphome/components/ntc/ntc.cpp

@@ -23,7 +23,7 @@ void NTC::process_(float value) {
   double v = this->a_ + this->b_ * lr + this->c_ * lr * lr * lr;
   auto temp = float(1.0 / v - 273.15);
 
-  ESP_LOGV(TAG, "'%s' - Temperature: %.1f°C", this->name_.c_str(), temp);
+  ESP_LOGD(TAG, "'%s' - Temperature: %.1f°C", this->name_.c_str(), temp);
   this->publish_state(temp);
 }
 

esphome/components/opentherm/opentherm.cpp

@@ -561,9 +561,8 @@ const char *OpenTherm::message_id_to_str(MessageId id) {
 }
 
 void OpenTherm::debug_data(OpenthermData &data) {
-  char type_buf[9], id_buf[9], hb_buf[9], lb_buf[9];
-  ESP_LOGD(TAG, "%s %s %s %s", format_bin_to(type_buf, data.type), format_bin_to(id_buf, data.id),
-           format_bin_to(hb_buf, data.valueHB), format_bin_to(lb_buf, data.valueLB));
+  ESP_LOGD(TAG, "%s %s %s %s", format_bin(data.type).c_str(), format_bin(data.id).c_str(),
+           format_bin(data.valueHB).c_str(), format_bin(data.valueLB).c_str());
   ESP_LOGD(TAG, "type: %s; id: %u; HB: %u; LB: %u; uint_16: %u; float: %f",
            this->message_type_to_str((MessageType) data.type), data.id, data.valueHB, data.valueLB, data.u16(),
            data.f88());

esphome/components/pca6416a/pca6416a.cpp

@@ -181,7 +181,7 @@ void PCA6416AGPIOPin::pin_mode(gpio::Flags flags) { this->parent_->pin_mode(this
 bool PCA6416AGPIOPin::digital_read() { return this->parent_->digital_read(this->pin_) != this->inverted_; }
 void PCA6416AGPIOPin::digital_write(bool value) { this->parent_->digital_write(this->pin_, value != this->inverted_); }
 size_t PCA6416AGPIOPin::dump_summary(char *buffer, size_t len) const {
-  return buf_append_printf(buffer, len, 0, "%u via PCA6416A", this->pin_);
+  return snprintf(buffer, len, "%u via PCA6416A", this->pin_);
 }
 
 }  // namespace pca6416a

esphome/components/pca9554/pca9554.cpp

@@ -130,7 +130,7 @@ void PCA9554GPIOPin::pin_mode(gpio::Flags flags) { this->parent_->pin_mode(this-
 bool PCA9554GPIOPin::digital_read() { return this->parent_->digital_read(this->pin_) != this->inverted_; }
 void PCA9554GPIOPin::digital_write(bool value) { this->parent_->digital_write(this->pin_, value != this->inverted_); }
 size_t PCA9554GPIOPin::dump_summary(char *buffer, size_t len) const {
-  return buf_append_printf(buffer, len, 0, "%u via PCA9554", this->pin_);
+  return snprintf(buffer, len, "%u via PCA9554", this->pin_);
 }
 
 }  // namespace pca9554

esphome/components/pcf8574/pcf8574.cpp

@@ -107,7 +107,7 @@ void PCF8574GPIOPin::pin_mode(gpio::Flags flags) { this->parent_->pin_mode(this-
 bool PCF8574GPIOPin::digital_read() { return this->parent_->digital_read(this->pin_) != this->inverted_; }
 void PCF8574GPIOPin::digital_write(bool value) { this->parent_->digital_write(this->pin_, value != this->inverted_); }
 size_t PCF8574GPIOPin::dump_summary(char *buffer, size_t len) const {
-  return buf_append_printf(buffer, len, 0, "%u via PCF8574", this->pin_);
+  return snprintf(buffer, len, "%u via PCF8574", this->pin_);
 }
 
 }  // namespace pcf8574

esphome/components/pi4ioe5v6408/pi4ioe5v6408.cpp

@@ -165,7 +165,7 @@ void PI4IOE5V6408GPIOPin::digital_write(bool value) {
   this->parent_->digital_write(this->pin_, value != this->inverted_);
 }
 size_t PI4IOE5V6408GPIOPin::dump_summary(char *buffer, size_t len) const {
-  return buf_append_printf(buffer, len, 0, "%u via PI4IOE5V6408", this->pin_);
+  return snprintf(buffer, len, "%u via PI4IOE5V6408", this->pin_);
 }
 
 }  // namespace pi4ioe5v6408

esphome/components/pipsolar/output/pipsolar_output.cpp

@@ -8,8 +8,8 @@ namespace pipsolar {
 static const char *const TAG = "pipsolar.output";
 
 void PipsolarOutput::write_state(float state) {
-  char tmp[16];
-  snprintf(tmp, sizeof(tmp), this->set_command_, state);
+  char tmp[10];
+  sprintf(tmp, this->set_command_.c_str(), state);
 
   if (std::find(this->possible_values_.begin(), this->possible_values_.end(), state) != this->possible_values_.end()) {
     ESP_LOGD(TAG, "Will write: %s out of value %f / %02.0f", tmp, state, state);

esphome/components/pipsolar/output/pipsolar_output.h

@@ -15,15 +15,13 @@ class PipsolarOutput : public output::FloatOutput {
  public:
   PipsolarOutput() {}
   void set_parent(Pipsolar *parent) { this->parent_ = parent; }
-  void set_set_command(const char *command) { this->set_command_ = command; }
-  /// Prevent accidental use of std::string which would dangle
-  void set_set_command(const std::string &command) = delete;
+  void set_set_command(const std::string &command) { this->set_command_ = command; };
   void set_possible_values(std::vector<float> possible_values) { this->possible_values_ = std::move(possible_values); }
-  void set_value(float value) { this->write_state(value); }
+  void set_value(float value) { this->write_state(value); };
 
  protected:
   void write_state(float state) override;
-  const char *set_command_{nullptr};
+  std::string set_command_;
   Pipsolar *parent_;
   std::vector<float> possible_values_;
 };

esphome/components/pipsolar/switch/pipsolar_switch.cpp

@@ -9,9 +9,14 @@ static const char *const TAG = "pipsolar.switch";
 
 void PipsolarSwitch::dump_config() { LOG_SWITCH("", "Pipsolar Switch", this); }
 void PipsolarSwitch::write_state(bool state) {
-  const char *command = state ? this->on_command_ : this->off_command_;
-  if (command != nullptr) {
-    this->parent_->queue_command(command);
+  if (state) {
+    if (!this->on_command_.empty()) {
+      this->parent_->queue_command(this->on_command_);
+    }
+  } else {
+    if (!this->off_command_.empty()) {
+      this->parent_->queue_command(this->off_command_);
+    }
   }
 }
 

esphome/components/pipsolar/switch/pipsolar_switch.h

@@ -9,18 +9,15 @@ namespace pipsolar {
 class Pipsolar;
 class PipsolarSwitch : public switch_::Switch, public Component {
  public:
-  void set_parent(Pipsolar *parent) { this->parent_ = parent; }
-  void set_on_command(const char *command) { this->on_command_ = command; }
-  void set_off_command(const char *command) { this->off_command_ = command; }
-  /// Prevent accidental use of std::string which would dangle
-  void set_on_command(const std::string &command) = delete;
-  void set_off_command(const std::string &command) = delete;
+  void set_parent(Pipsolar *parent) { this->parent_ = parent; };
+  void set_on_command(const std::string &command) { this->on_command_ = command; };
+  void set_off_command(const std::string &command) { this->off_command_ = command; };
   void dump_config() override;
 
  protected:
   void write_state(bool state) override;
-  const char *on_command_{nullptr};
-  const char *off_command_{nullptr};
+  std::string on_command_;
+  std::string off_command_;
   Pipsolar *parent_;
 };
 

esphome/components/rc522_spi/rc522_spi.cpp

@@ -1,5 +1,4 @@
 #include "rc522_spi.h"
-#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
 // Based on:
@@ -71,7 +70,7 @@ void RC522Spi::pcd_read_register(PcdRegister reg,  ///< The register to read fro
     index++;
 
 #ifdef ESPHOME_LOG_HAS_VERY_VERBOSE
-    buf_append_printf(cstrb, sizeof(cstrb), 0, " %x", values[0]);
+    sprintf(cstrb, " %x", values[0]);
     buf.append(cstrb);
 #endif
   }
@@ -79,7 +78,7 @@ void RC522Spi::pcd_read_register(PcdRegister reg,  ///< The register to read fro
     values[index] = transfer_byte(address);  // Read value and tell that we want to read the same address again.
 
 #ifdef ESPHOME_LOG_HAS_VERY_VERBOSE
-    buf_append_printf(cstrb, sizeof(cstrb), 0, " %x", values[index]);
+    sprintf(cstrb, " %x", values[index]);
     buf.append(cstrb);
 #endif
 
@@ -89,7 +88,7 @@ void RC522Spi::pcd_read_register(PcdRegister reg,  ///< The register to read fro
 
 #ifdef ESPHOME_LOG_HAS_VERY_VERBOSE
   buf = buf + " ";
-  buf_append_printf(cstrb, sizeof(cstrb), 0, "%x", values[index]);
+  sprintf(cstrb, "%x", values[index]);
   buf.append(cstrb);
 
   ESP_LOGVV(TAG, "read_register_array_(%x, %d, , %d) -> %s", reg, count, rx_align, buf.c_str());
@@ -128,7 +127,7 @@ void RC522Spi::pcd_write_register(PcdRegister reg,  ///< The register to write t
     transfer_byte(values[index]);
 
 #ifdef ESPHOME_LOG_HAS_VERY_VERBOSE
-    buf_append_printf(cstrb, sizeof(cstrb), 0, " %x", values[index]);
+    sprintf(cstrb, " %x", values[index]);
     buf.append(cstrb);
 #endif
   }

esphome/components/remote_base/aeha_protocol.cpp

@@ -85,8 +85,8 @@ optional<AEHAData> AEHAProtocol::decode(RemoteReceiveData src) {
 std::string AEHAProtocol::format_data_(const std::vector<uint8_t> &data) {
   std::string out;
   for (uint8_t byte : data) {
-    char buf[8];  // "0x%02X," = 5 chars + null + margin
-    snprintf(buf, sizeof(buf), "0x%02X,", byte);
+    char buf[6];
+    sprintf(buf, "0x%02X,", byte);
     out += buf;
   }
   out.pop_back();

esphome/components/remote_base/raw_protocol.cpp

@@ -1,5 +1,4 @@
 #include "raw_protocol.h"
-#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
 namespace esphome {
@@ -9,30 +8,36 @@ static const char *const TAG = "remote.raw";
 
 bool RawDumper::dump(RemoteReceiveData src) {
   char buffer[256];
-  size_t pos = buf_append_printf(buffer, sizeof(buffer), 0, "Received Raw: ");
+  uint32_t buffer_offset = 0;
+  buffer_offset += sprintf(buffer, "Received Raw: ");
 
   for (int32_t i = 0; i < src.size() - 1; i++) {
     const int32_t value = src[i];
-    size_t prev_pos = pos;
+    const uint32_t remaining_length = sizeof(buffer) - buffer_offset;
+    int written;
 
     if (i + 1 < src.size() - 1) {
-      pos = buf_append_printf(buffer, sizeof(buffer), pos, "%" PRId32 ", ", value);
+      written = snprintf(buffer + buffer_offset, remaining_length, "%" PRId32 ", ", value);
     } else {
-      pos = buf_append_printf(buffer, sizeof(buffer), pos, "%" PRId32, value);
+      written = snprintf(buffer + buffer_offset, remaining_length, "%" PRId32, value);
     }
 
-    if (pos >= sizeof(buffer) - 1) {
-      // buffer full, flush and continue
-      buffer[prev_pos] = '\0';
+    if (written < 0 || written >= int(remaining_length)) {
+      // write failed, flush...
+      buffer[buffer_offset] = '\0';
       ESP_LOGI(TAG, "%s", buffer);
+      buffer_offset = 0;
+      written = sprintf(buffer, "  ");
       if (i + 1 < src.size() - 1) {
-        pos = buf_append_printf(buffer, sizeof(buffer), 0, "  %" PRId32 ", ", value);
+        written += sprintf(buffer + written, "%" PRId32 ", ", value);
       } else {
-        pos = buf_append_printf(buffer, sizeof(buffer), 0, "  %" PRId32, value);
+        written += sprintf(buffer + written, "%" PRId32, value);
       }
     }
+
+    buffer_offset += written;
   }
-  if (pos != 0) {
+  if (buffer_offset != 0) {
     ESP_LOGI(TAG, "%s", buffer);
   }
   return true;

esphome/components/remote_base/remote_base.cpp

@@ -1,7 +1,8 @@
 #include "remote_base.h"
-#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
+#include <cinttypes>
+
 namespace esphome {
 namespace remote_base {
 
@@ -158,8 +159,8 @@ void RemoteTransmitData::set_data_from_packed_sint32(const uint8_t *data, size_t
   }
 }
 
-bool RemoteTransmitData::set_data_from_base64url(const std::string &base64url) {
-  return base64_decode_int32_vector(base64url, this->data_);
+bool RemoteTransmitData::set_data_from_base85(const std::string &base85) {
+  return base85_decode_int32_vector(base85, this->data_);
 }
 
 /* RemoteTransmitterBase */
@@ -168,31 +169,36 @@ void RemoteTransmitterBase::send_(uint32_t send_times, uint32_t send_wait) {
 #ifdef ESPHOME_LOG_HAS_VERY_VERBOSE
   const auto &vec = this->temp_.get_data();
   char buffer[256];
-  size_t pos = buf_append_printf(buffer, sizeof(buffer), 0,
-                                 "Sending times=%" PRIu32 " wait=%" PRIu32 "ms: ", send_times, send_wait);
+  uint32_t buffer_offset = 0;
+  buffer_offset += sprintf(buffer, "Sending times=%" PRIu32 " wait=%" PRIu32 "ms: ", send_times, send_wait);
 
   for (size_t i = 0; i < vec.size(); i++) {
     const int32_t value = vec[i];
-    size_t prev_pos = pos;
+    const uint32_t remaining_length = sizeof(buffer) - buffer_offset;
+    int written;
 
     if (i + 1 < vec.size()) {
-      pos = buf_append_printf(buffer, sizeof(buffer), pos, "%" PRId32 ", ", value);
+      written = snprintf(buffer + buffer_offset, remaining_length, "%" PRId32 ", ", value);
     } else {
-      pos = buf_append_printf(buffer, sizeof(buffer), pos, "%" PRId32, value);
+      written = snprintf(buffer + buffer_offset, remaining_length, "%" PRId32, value);
     }
 
-    if (pos >= sizeof(buffer) - 1) {
-      // buffer full, flush and continue
-      buffer[prev_pos] = '\0';
+    if (written < 0 || written >= int(remaining_length)) {
+      // write failed, flush...
+      buffer[buffer_offset] = '\0';
       ESP_LOGVV(TAG, "%s", buffer);
+      buffer_offset = 0;
+      written = sprintf(buffer, "  ");
       if (i + 1 < vec.size()) {
-        pos = buf_append_printf(buffer, sizeof(buffer), 0, "  %" PRId32 ", ", value);
+        written += sprintf(buffer + written, "%" PRId32 ", ", value);
       } else {
-        pos = buf_append_printf(buffer, sizeof(buffer), 0, "  %" PRId32, value);
+        written += sprintf(buffer + written, "%" PRId32, value);
       }
     }
+
+    buffer_offset += written;
   }
-  if (pos != 0) {
+  if (buffer_offset != 0) {
     ESP_LOGVV(TAG, "%s", buffer);
   }
 #endif

esphome/components/remote_base/remote_base.h

@@ -36,11 +36,11 @@ class RemoteTransmitData {
   /// @param len Length of the buffer in bytes
   /// @param count Number of values (for reserve optimization)
   void set_data_from_packed_sint32(const uint8_t *data, size_t len, size_t count);
-  /// Set data from base64url-encoded little-endian int32 values
-  /// Base64url is URL-safe: uses '-' instead of '+', '_' instead of '/'
-  /// @param base64url Base64url-encoded string of little-endian int32 values
+  /// Set data from base85-encoded int32 values
+  /// Decodes directly into internal buffer (zero heap allocations)
+  /// @param base85 Base85-encoded string (5 chars per int32 value)
   /// @return true if successful, false if decode failed or invalid size
-  bool set_data_from_base64url(const std::string &base64url);
+  bool set_data_from_base85(const std::string &base85);
   void reset() {
     this->data_.clear();
     this->carrier_frequency_ = 0;

esphome/components/resistance/resistance_sensor.cpp

@@ -39,7 +39,7 @@ void ResistanceSensor::process_(float value) {
   }
 
   res *= this->resistor_;
-  ESP_LOGV(TAG, "'%s' - Resistance %.1fΩ", this->name_.c_str(), res);
+  ESP_LOGD(TAG, "'%s' - Resistance %.1fΩ", this->name_.c_str(), res);
   this->publish_state(res);
 }
 

esphome/components/select/__init__.py

@@ -8,20 +8,17 @@ from esphome.const import (
     CONF_ICON,
     CONF_ID,
     CONF_INDEX,
-    CONF_LAMBDA,
     CONF_MODE,
     CONF_MQTT_ID,
     CONF_ON_VALUE,
     CONF_OPERATION,
     CONF_OPTION,
-    CONF_OPTIONS,
     CONF_TRIGGER_ID,
     CONF_WEB_SERVER,
 )
-from esphome.core import CORE, ID, CoroPriority, coroutine_with_priority
+from esphome.core import CORE, CoroPriority, coroutine_with_priority
 from esphome.core.entity_helpers import entity_duplicate_validator, setup_entity
-from esphome.cpp_generator import MockObjClass, TemplateArguments
-from esphome.cpp_types import global_ns
+from esphome.cpp_generator import MockObjClass
 
 CODEOWNERS = ["@esphome/core"]
 IS_PLATFORM_COMPONENT = True
@@ -33,7 +30,7 @@ SelectPtr = Select.operator("ptr")
 # Triggers
 SelectStateTrigger = select_ns.class_(
     "SelectStateTrigger",
-    automation.Trigger.template(cg.StringRef, cg.size_t),
+    automation.Trigger.template(cg.std_string, cg.size_t),
 )
 
 # Actions
@@ -41,9 +38,6 @@ SelectSetAction = select_ns.class_("SelectSetAction", automation.Action)
 SelectSetIndexAction = select_ns.class_("SelectSetIndexAction", automation.Action)
 SelectOperationAction = select_ns.class_("SelectOperationAction", automation.Action)
 
-# Conditions
-SelectIsCondition = select_ns.class_("SelectIsCondition", automation.Condition)
-
 # Enums
 SelectOperation = select_ns.enum("SelectOperation")
 SELECT_OPERATION_OPTIONS = {
@@ -100,7 +94,7 @@ async def setup_select_core_(var, config, *, options: list[str]):
     for conf in config.get(CONF_ON_VALUE, []):
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
         await automation.build_automation(
-            trigger, [(cg.StringRef, "x"), (cg.size_t, "i")], conf
+            trigger, [(cg.std_string, "x"), (cg.size_t, "i")], conf
         )
 
     if (mqtt_id := config.get(CONF_MQTT_ID)) is not None:
@@ -171,41 +165,6 @@ async def select_set_index_to_code(config, action_id, template_arg, args):
     return var
 
 
-@automation.register_condition(
-    "select.is",
-    SelectIsCondition,
-    OPERATION_BASE_SCHEMA.extend(
-        {
-            cv.Optional(CONF_OPTIONS): cv.All(
-                cv.ensure_list(cv.string_strict), cv.Length(min=1)
-            ),
-            cv.Optional(CONF_LAMBDA): cv.returning_lambda,
-        }
-    ).add_extra(cv.has_exactly_one_key(CONF_OPTIONS, CONF_LAMBDA)),
-)
-async def select_is_to_code(config, condition_id, template_arg, args):
-    paren = await cg.get_variable(config[CONF_ID])
-    if options := config.get(CONF_OPTIONS):
-        # List of constant options
-        # Create a constexpr and pass that with a template length
-        arr_id = ID(
-            f"{condition_id}_data",
-            is_declaration=True,
-            type=global_ns.namespace("constexpr char * const"),
-        )
-        arg = cg.static_const_array(arr_id, cg.ArrayInitializer(*options))
-        template_arg = TemplateArguments(len(options), *template_arg)
-    else:
-        # Lambda
-        arg = await cg.process_lambda(
-            config[CONF_LAMBDA],
-            [(global_ns.namespace("StringRef &").operator("const"), "current")] + args,
-            return_type=cg.bool_,
-        )
-        template_arg = TemplateArguments(0, *template_arg)
-    return cg.new_Pvariable(condition_id, template_arg, paren, arg)
-
-
 @automation.register_action(
     "select.operation",
     SelectOperationAction,

esphome/components/select/automation.h

@@ -6,11 +6,11 @@
 
 namespace esphome::select {
 
-class SelectStateTrigger : public Trigger<StringRef, size_t> {
+class SelectStateTrigger : public Trigger<std::string, size_t> {
  public:
   explicit SelectStateTrigger(Select *parent) : parent_(parent) {
     parent->add_on_state_callback(
-        [this](size_t index) { this->trigger(StringRef(this->parent_->option_at(index)), index); });
+        [this](size_t index) { this->trigger(std::string(this->parent_->option_at(index)), index); });
   }
 
  protected:
@@ -66,34 +66,4 @@ template<typename... Ts> class SelectOperationAction : public Action<Ts...> {
   Select *select_;
 };
 
-template<size_t N, typename... Ts> class SelectIsCondition : public Condition<Ts...> {
- public:
-  SelectIsCondition(Select *parent, const char *const *option_list) : parent_(parent), option_list_(option_list) {}
-
-  bool check(const Ts &...x) override {
-    auto current = this->parent_->current_option();
-    for (size_t i = 0; i != N; i++) {
-      if (current == this->option_list_[i]) {
-        return true;
-      }
-    }
-    return false;
-  }
-
- protected:
-  Select *parent_;
-  const char *const *option_list_;
-};
-
-template<typename... Ts> class SelectIsCondition<0, Ts...> : public Condition<Ts...> {
- public:
-  SelectIsCondition(Select *parent, std::function<bool(const StringRef &, const Ts &...)> &&f)
-      : parent_(parent), f_(f) {}
-
-  bool check(const Ts &...x) override { return this->f_(this->parent_->current_option(), x...); }
-
- protected:
-  Select *parent_;
-  std::function<bool(const StringRef &, const Ts &...)> f_;
-};
 }  // namespace esphome::select

esphome/components/sim800l/sim800l.cpp

@@ -1,5 +1,4 @@
 #include "sim800l.h"
-#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include <cstring>
 
@@ -51,8 +50,8 @@ void Sim800LComponent::update() {
   } else if (state_ == STATE_RECEIVED_SMS) {
     // Serial Buffer should have flushed.
     // Send cmd to delete received sms
-    char delete_cmd[20];  // "AT+CMGD=" (8) + uint8_t (max 3) + null = 12 <= 20
-    buf_append_printf(delete_cmd, sizeof(delete_cmd), 0, "AT+CMGD=%d", this->parse_index_);
+    char delete_cmd[20];
+    sprintf(delete_cmd, "AT+CMGD=%d", this->parse_index_);
     this->send_cmd_(delete_cmd);
     this->state_ = STATE_CHECK_SMS;
     this->expect_ack_ = true;

esphome/components/sml/sml_parser.cpp

@@ -104,10 +104,7 @@ std::vector<ObisInfo> SmlFile::get_obis_info() {
 std::string bytes_repr(const BytesView &buffer) {
   std::string repr;
   for (auto const value : buffer) {
-    // max 3: 2 hex digits + null
-    char hex_buf[3];
-    snprintf(hex_buf, sizeof(hex_buf), "%02x", static_cast<unsigned int>(value));
-    repr += hex_buf;
+    repr += str_sprintf("%02x", value & 0xff);
   }
   return repr;
 }
@@ -149,11 +146,7 @@ ObisInfo::ObisInfo(const BytesView &server_id, const SmlNode &val_list_entry) :
 }
 
 std::string ObisInfo::code_repr() const {
-  // max 20: "255-255:255.255.255" (19 chars) + null
-  char buf[20];
-  snprintf(buf, sizeof(buf), "%d-%d:%d.%d.%d", this->code[0], this->code[1], this->code[2], this->code[3],
-           this->code[4]);
-  return buf;
+  return str_sprintf("%d-%d:%d.%d.%d", this->code[0], this->code[1], this->code[2], this->code[3], this->code[4]);
 }
 
 }  // namespace sml

esphome/components/sn74hc165/sn74hc165.cpp

@@ -65,7 +65,7 @@ float SN74HC165Component::get_setup_priority() const { return setup_priority::IO
 bool SN74HC165GPIOPin::digital_read() { return this->parent_->digital_read_(this->pin_) != this->inverted_; }
 
 size_t SN74HC165GPIOPin::dump_summary(char *buffer, size_t len) const {
-  return buf_append_printf(buffer, len, 0, "%u via SN74HC165", this->pin_);
+  return snprintf(buffer, len, "%u via SN74HC165", this->pin_);
 }
 
 }  // namespace sn74hc165

esphome/components/sn74hc595/sn74hc595.cpp

@@ -94,7 +94,7 @@ void SN74HC595GPIOPin::digital_write(bool value) {
   this->parent_->digital_write_(this->pin_, value != this->inverted_);
 }
 size_t SN74HC595GPIOPin::dump_summary(char *buffer, size_t len) const {
-  return buf_append_printf(buffer, len, 0, "%u via SN74HC595", this->pin_);
+  return snprintf(buffer, len, "%u via SN74HC595", this->pin_);
 }
 
 }  // namespace sn74hc595

esphome/components/socket/socket.cpp

@@ -107,9 +107,9 @@ std::unique_ptr<Socket> socket_ip_loop_monitored(int type, int protocol) {
 #endif /* USE_NETWORK_IPV6 */
 }
 
-socklen_t set_sockaddr(struct sockaddr *addr, socklen_t addrlen, const char *ip_address, uint16_t port) {
+socklen_t set_sockaddr(struct sockaddr *addr, socklen_t addrlen, const std::string &ip_address, uint16_t port) {
 #if USE_NETWORK_IPV6
-  if (strchr(ip_address, ':') != nullptr) {
+  if (ip_address.find(':') != std::string::npos) {
     if (addrlen < sizeof(sockaddr_in6)) {
       errno = EINVAL;
       return 0;
@@ -121,14 +121,14 @@ socklen_t set_sockaddr(struct sockaddr *addr, socklen_t addrlen, const char *ip_
 
 #ifdef USE_SOCKET_IMPL_BSD_SOCKETS
     // Use standard inet_pton for BSD sockets
-    if (inet_pton(AF_INET6, ip_address, &server->sin6_addr) != 1) {
+    if (inet_pton(AF_INET6, ip_address.c_str(), &server->sin6_addr) != 1) {
       errno = EINVAL;
       return 0;
     }
 #else
     // Use LWIP-specific functions
     ip6_addr_t ip6;
-    inet6_aton(ip_address, &ip6);
+    inet6_aton(ip_address.c_str(), &ip6);
     memcpy(server->sin6_addr.un.u32_addr, ip6.addr, sizeof(ip6.addr));
 #endif
     return sizeof(sockaddr_in6);
@@ -141,7 +141,7 @@ socklen_t set_sockaddr(struct sockaddr *addr, socklen_t addrlen, const char *ip_
   auto *server = reinterpret_cast<sockaddr_in *>(addr);
   memset(server, 0, sizeof(sockaddr_in));
   server->sin_family = AF_INET;
-  server->sin_addr.s_addr = inet_addr(ip_address);
+  server->sin_addr.s_addr = inet_addr(ip_address.c_str());
   server->sin_port = htons(port);
   return sizeof(sockaddr_in);
 }

esphome/components/socket/socket.h

@@ -87,17 +87,7 @@ std::unique_ptr<Socket> socket_loop_monitored(int domain, int type, int protocol
 std::unique_ptr<Socket> socket_ip_loop_monitored(int type, int protocol);
 
 /// Set a sockaddr to the specified address and port for the IP version used by socket_ip().
-/// @param addr Destination sockaddr structure
-/// @param addrlen Size of the addr buffer
-/// @param ip_address Null-terminated IP address string (IPv4 or IPv6)
-/// @param port Port number in host byte order
-/// @return Size of the sockaddr structure used, or 0 on error
-socklen_t set_sockaddr(struct sockaddr *addr, socklen_t addrlen, const char *ip_address, uint16_t port);
-
-/// Convenience overload for std::string (backward compatible).
-inline socklen_t set_sockaddr(struct sockaddr *addr, socklen_t addrlen, const std::string &ip_address, uint16_t port) {
-  return set_sockaddr(addr, addrlen, ip_address.c_str(), port);
-}
+socklen_t set_sockaddr(struct sockaddr *addr, socklen_t addrlen, const std::string &ip_address, uint16_t port);
 
 /// Set a sockaddr to the any address and specified port for the IP version used by socket_ip().
 socklen_t set_sockaddr_any(struct sockaddr *addr, socklen_t addrlen, uint16_t port);

esphome/components/status/binary_sensor.py

@@ -7,14 +7,14 @@ DEPENDENCIES = ["network"]
 
 status_ns = cg.esphome_ns.namespace("status")
 StatusBinarySensor = status_ns.class_(
-    "StatusBinarySensor", binary_sensor.BinarySensor, cg.PollingComponent
+    "StatusBinarySensor", binary_sensor.BinarySensor, cg.Component
 )
 
 CONFIG_SCHEMA = binary_sensor.binary_sensor_schema(
     StatusBinarySensor,
     device_class=DEVICE_CLASS_CONNECTIVITY,
     entity_category=ENTITY_CATEGORY_DIAGNOSTIC,
-).extend(cv.polling_component_schema("1s"))
+).extend(cv.COMPONENT_SCHEMA)
 
 
 async def to_code(config):

esphome/components/status/status_binary_sensor.cpp

@@ -10,11 +10,12 @@
 #include "esphome/components/api/api_server.h"
 #endif
 
-namespace esphome::status {
+namespace esphome {
+namespace status {
 
 static const char *const TAG = "status";
 
-void StatusBinarySensor::update() {
+void StatusBinarySensor::loop() {
   bool status = network::is_connected();
 #ifdef USE_MQTT
   if (mqtt::global_mqtt_client != nullptr) {
@@ -32,4 +33,5 @@ void StatusBinarySensor::update() {
 void StatusBinarySensor::setup() { this->publish_initial_state(false); }
 void StatusBinarySensor::dump_config() { LOG_BINARY_SENSOR("", "Status Binary Sensor", this); }
 
-}  // namespace esphome::status
+}  // namespace status
+}  // namespace esphome

esphome/components/status/status_binary_sensor.h

@@ -3,11 +3,12 @@
 #include "esphome/core/component.h"
 #include "esphome/components/binary_sensor/binary_sensor.h"
 
-namespace esphome::status {
+namespace esphome {
+namespace status {
 
-class StatusBinarySensor : public binary_sensor::BinarySensor, public PollingComponent {
+class StatusBinarySensor : public binary_sensor::BinarySensor, public Component {
  public:
-  void update() override;
+  void loop() override;
 
   void setup() override;
   void dump_config() override;
@@ -15,4 +16,5 @@ class StatusBinarySensor : public binary_sensor::BinarySensor, public PollingCom
   bool is_status_binary_sensor() const override { return true; }
 };
 
-}  // namespace esphome::status
+}  // namespace status
+}  // namespace esphome

esphome/components/sun/text_sensor/sun_text_sensor.h

@@ -14,9 +14,7 @@ class SunTextSensor : public text_sensor::TextSensor, public PollingComponent {
   void set_parent(Sun *parent) { parent_ = parent; }
   void set_elevation(double elevation) { elevation_ = elevation; }
   void set_sunrise(bool sunrise) { sunrise_ = sunrise; }
-  void set_format(const char *format) { this->format_ = format; }
-  /// Prevent accidental use of std::string which would dangle
-  void set_format(const std::string &format) = delete;
+  void set_format(const std::string &format) { format_ = format; }
 
   void update() override {
     optional<ESPTime> res;
@@ -31,14 +29,14 @@ class SunTextSensor : public text_sensor::TextSensor, public PollingComponent {
     }
 
     char buf[ESPTime::STRFTIME_BUFFER_SIZE];
-    size_t len = res->strftime_to(buf, this->format_);
+    size_t len = res->strftime_to(buf, this->format_.c_str());
     this->publish_state(buf, len);
   }
 
   void dump_config() override;
 
  protected:
-  const char *format_{nullptr};
+  std::string format_{};
   Sun *parent_;
   double elevation_;
   bool sunrise_;

esphome/components/sx1509/sx1509_gpio_pin.cpp

@@ -13,7 +13,7 @@ void SX1509GPIOPin::pin_mode(gpio::Flags flags) { this->parent_->pin_mode(this->
 bool SX1509GPIOPin::digital_read() { return this->parent_->digital_read(this->pin_) != this->inverted_; }
 void SX1509GPIOPin::digital_write(bool value) { this->parent_->digital_write(this->pin_, value != this->inverted_); }
 size_t SX1509GPIOPin::dump_summary(char *buffer, size_t len) const {
-  return buf_append_printf(buffer, len, 0, "%u via sx1509", this->pin_);
+  return snprintf(buffer, len, "%u via sx1509", this->pin_);
 }
 
 }  // namespace sx1509

esphome/components/syslog/esphome_syslog.cpp

@@ -47,27 +47,29 @@ void Syslog::log_(const int level, const char *tag, const char *message, size_t
   size_t remaining = sizeof(packet);
 
   // Write PRI - abort if this fails as packet would be malformed
-  offset = buf_append_printf(packet, sizeof(packet), 0, "<%d>", pri);
-  if (offset == 0) {
-    return;  // PRI always produces at least "<0>" (3 chars), so 0 means error
+  int ret = snprintf(packet, remaining, "<%d>", pri);
+  if (ret <= 0 || static_cast<size_t>(ret) >= remaining) {
+    return;
   }
-  remaining -= offset;
+  offset = ret;
+  remaining -= ret;
 
   // Write timestamp directly into packet (RFC 5424: use "-" if time not valid or strftime fails)
   auto now = this->time_->now();
   size_t ts_written = now.is_valid() ? now.strftime(packet + offset, remaining, "%b %e %H:%M:%S") : 0;
   if (ts_written > 0) {
     offset += ts_written;
+    remaining -= ts_written;
   } else if (remaining > 0) {
     packet[offset++] = '-';
+    remaining--;
   }
 
   // Write hostname, tag, and message
-  offset = buf_append_printf(packet, sizeof(packet), offset, " %s %s: %.*s", App.get_name().c_str(), tag, (int) len,
-                             message);
-  // Clamp to exclude null terminator position if buffer was filled
-  if (offset >= sizeof(packet)) {
-    offset = sizeof(packet) - 1;
+  ret = snprintf(packet + offset, remaining, " %s %s: %.*s", App.get_name().c_str(), tag, (int) len, message);
+  if (ret > 0) {
+    // snprintf returns chars that would be written; clamp to actual buffer space
+    offset += std::min(static_cast<size_t>(ret), remaining > 0 ? remaining - 1 : 0);
   }
 
   if (offset > 0) {

esphome/components/tca9555/tca9555.cpp

@@ -139,7 +139,7 @@ void TCA9555GPIOPin::pin_mode(gpio::Flags flags) { this->parent_->pin_mode(this-
 bool TCA9555GPIOPin::digital_read() { return this->parent_->digital_read(this->pin_) != this->inverted_; }
 void TCA9555GPIOPin::digital_write(bool value) { this->parent_->digital_write(this->pin_, value != this->inverted_); }
 size_t TCA9555GPIOPin::dump_summary(char *buffer, size_t len) const {
-  return buf_append_printf(buffer, len, 0, "%u via TCA9555", this->pin_);
+  return snprintf(buffer, len, "%u via TCA9555", this->pin_);
 }
 
 }  // namespace tca9555

esphome/components/template/alarm_control_panel/__init__.py

@@ -118,7 +118,8 @@ async def to_code(config):
     var = await alarm_control_panel.new_alarm_control_panel(config)
     await cg.register_component(var, config)
     if CONF_CODES in config:
-        cg.add(var.set_codes(config[CONF_CODES]))
+        for acode in config[CONF_CODES]:
+            cg.add(var.add_code(acode))
         if CONF_REQUIRES_CODE_TO_ARM in config:
             cg.add(var.set_requires_code_to_arm(config[CONF_REQUIRES_CODE_TO_ARM]))
 

esphome/components/template/alarm_control_panel/template_alarm_control_panel.cpp

@@ -206,13 +206,7 @@ bool TemplateAlarmControlPanel::is_code_valid_(optional<std::string> code) {
   if (!this->codes_.empty()) {
     if (code.has_value()) {
       ESP_LOGVV(TAG, "Checking code: %s", code.value().c_str());
-      // Use strcmp for const char* comparison
-      const char *code_cstr = code.value().c_str();
-      for (const char *stored_code : this->codes_) {
-        if (strcmp(stored_code, code_cstr) == 0)
-          return true;
-      }
-      return false;
+      return (std::count(this->codes_.begin(), this->codes_.end(), code.value()) == 1);
     }
     ESP_LOGD(TAG, "No code provided");
     return false;

esphome/components/template/alarm_control_panel/template_alarm_control_panel.h

@@ -1,7 +1,6 @@
 #pragma once
 
 #include <cinttypes>
-#include <cstring>
 #include <vector>
 
 #include "esphome/core/automation.h"
@@ -87,14 +86,11 @@ class TemplateAlarmControlPanel final : public alarm_control_panel::AlarmControl
                   AlarmSensorType type = ALARM_SENSOR_TYPE_DELAYED);
 #endif
 
-  /** Set the codes (from initializer list).
+  /** add a code
    *
-   * @param codes The list of valid codes
+   * @param code The code
    */
-  void set_codes(std::initializer_list<const char *> codes) { this->codes_ = codes; }
-
-  // Deleted overload to catch incorrect std::string usage at compile time
-  void set_codes(std::initializer_list<std::string> codes) = delete;
+  void add_code(const std::string &code) { this->codes_.push_back(code); }
 
   /** set requires a code to arm
    *
@@ -159,8 +155,8 @@ class TemplateAlarmControlPanel final : public alarm_control_panel::AlarmControl
   uint32_t pending_time_;
   // the time in trigger
   uint32_t trigger_time_;
-  // a list of codes (const char* pointers to string literals in flash)
-  FixedVector<const char *> codes_;
+  // a list of codes
+  std::vector<std::string> codes_;
   // requires a code to arm
   bool requires_code_to_arm_ = false;
   bool supports_arm_home_ = false;

esphome/components/template/select/__init__.py

@@ -88,5 +88,5 @@ async def to_code(config):
 
     if CONF_SET_ACTION in config:
         await automation.build_automation(
-            var.get_set_trigger(), [(cg.StringRef, "x")], config[CONF_SET_ACTION]
+            var.get_set_trigger(), [(cg.std_string, "x")], config[CONF_SET_ACTION]
         )

esphome/components/template/select/template_select.cpp

@@ -41,7 +41,7 @@ void TemplateSelect::update() {
 }
 
 void TemplateSelect::control(size_t index) {
-  this->set_trigger_->trigger(StringRef(this->option_at(index)));
+  this->set_trigger_->trigger(std::string(this->option_at(index)));
 
   if (this->optimistic_)
     this->publish_state(index);

esphome/components/template/select/template_select.h

@@ -4,7 +4,6 @@
 #include "esphome/core/automation.h"
 #include "esphome/core/component.h"
 #include "esphome/core/preferences.h"
-#include "esphome/core/string_ref.h"
 #include "esphome/core/template_lambda.h"
 
 namespace esphome::template_ {
@@ -18,7 +17,7 @@ class TemplateSelect final : public select::Select, public PollingComponent {
   void dump_config() override;
   float get_setup_priority() const override { return setup_priority::HARDWARE; }
 
-  Trigger<StringRef> *get_set_trigger() const { return this->set_trigger_; }
+  Trigger<std::string> *get_set_trigger() const { return this->set_trigger_; }
   void set_optimistic(bool optimistic) { this->optimistic_ = optimistic; }
   void set_initial_option_index(size_t initial_option_index) { this->initial_option_index_ = initial_option_index; }
   void set_restore_value(bool restore_value) { this->restore_value_ = restore_value; }
@@ -28,7 +27,7 @@ class TemplateSelect final : public select::Select, public PollingComponent {
   bool optimistic_ = false;
   size_t initial_option_index_{0};
   bool restore_value_ = false;
-  Trigger<StringRef> *set_trigger_ = new Trigger<StringRef>();
+  Trigger<std::string> *set_trigger_ = new Trigger<std::string>();
   TemplateLambda<std::string> f_;
 
   ESPPreferenceObject pref_;