From ba82d968eb40372103f1e9b9844972e5ada95848 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sat, 8 Nov 2025 22:25:41 -0600
Subject: [PATCH] [sx127x] Optimize send_packet action memory usage - store
 static data in flash

---
 esphome/components/sx127x/__init__.py  |  6 +++++-
 esphome/components/sx127x/automation.h | 26 +++++++++++++++++---------
 tests/components/sx127x/common.yaml    | 11 +++++++++++
 3 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/esphome/components/sx127x/__init__.py b/esphome/components/sx127x/__init__.py
index 33b556db07..77cb61f7f8 100644
--- a/esphome/components/sx127x/__init__.py
+++ b/esphome/components/sx127x/__init__.py
@@ -3,6 +3,7 @@ import esphome.codegen as cg
 from esphome.components import spi
 import esphome.config_validation as cv
 from esphome.const import CONF_DATA, CONF_FREQUENCY, CONF_ID
+from esphome.core import ID
 
 MULTI_CONF = True
 CODEOWNERS = ["@swoboda1337"]
@@ -321,5 +322,8 @@ async def send_packet_action_to_code(config, action_id, template_arg, args):
         templ = await cg.templatable(data, args, cg.std_vector.template(cg.uint8))
         cg.add(var.set_data_template(templ))
     else:
-        cg.add(var.set_data_static(data))
+        # Generate static array in flash to avoid RAM copy
+        arr_id = ID(f"{action_id}_data", is_declaration=True, type=cg.uint8)
+        arr = cg.static_const_array(arr_id, cg.ArrayInitializer(*data))
+        cg.add(var.set_data_static(arr, len(data)))
     return var
diff --git a/esphome/components/sx127x/automation.h b/esphome/components/sx127x/automation.h
index eae16c11fa..52dbf37e09 100644
--- a/esphome/components/sx127x/automation.h
+++ b/esphome/components/sx127x/automation.h
@@ -14,28 +14,36 @@ template<typename... Ts> class RunImageCalAction : public Action<Ts...>, public
 
 template<typename... Ts> class SendPacketAction : public Action<Ts...>, public Parented<SX127x> {
  public:
-  void set_data_template(std::function<std::vector<uint8_t>(Ts...)> func) {
-    this->data_func_ = func;
+  void set_data_template(std::vector<uint8_t> (*func)(Ts...)) {
+    this->data_.func = func;
     this->static_ = false;
   }
 
-  void set_data_static(const std::vector<uint8_t> &data) {
-    this->data_static_ = data;
+  void set_data_static(const uint8_t *data, size_t len) {
+    this->data_.static_data.ptr = data;
+    this->data_.static_data.len = len;
     this->static_ = true;
   }
 
   void play(const Ts &...x) override {
+    std::vector<uint8_t> data;
     if (this->static_) {
-      this->parent_->transmit_packet(this->data_static_);
+      data.assign(this->data_.static_data.ptr, this->data_.static_data.ptr + this->data_.static_data.len);
     } else {
-      this->parent_->transmit_packet(this->data_func_(x...));
+      data = this->data_.func(x...);
     }
+    this->parent_->transmit_packet(data);
   }
 
  protected:
-  bool static_{false};
-  std::function<std::vector<uint8_t>(Ts...)> data_func_{};
-  std::vector<uint8_t> data_static_{};
+  bool static_{true};
+  union Data {
+    std::vector<uint8_t> (*func)(Ts...);
+    struct {
+      const uint8_t *ptr;
+      size_t len;
+    } static_data;
+  } data_;
 };
 
 template<typename... Ts> class SetModeTxAction : public Action<Ts...>, public Parented<SX127x> {
diff --git a/tests/components/sx127x/common.yaml b/tests/components/sx127x/common.yaml
index 540381fc08..6e48952fcc 100644
--- a/tests/components/sx127x/common.yaml
+++ b/tests/components/sx127x/common.yaml
@@ -26,6 +26,15 @@ sx127x:
       - sx127x.send_packet:
           data: [0xC5, 0x51, 0x78, 0x82, 0xB7, 0xF9, 0x9C, 0x5C]
 
+number:
+  - platform: template
+    name: "SX127x Number"
+    id: my_number
+    optimistic: true
+    min_value: 0
+    max_value: 100
+    step: 1
+
 button:
   - platform: template
     name: "SX127x Button"
@@ -38,3 +47,5 @@ button:
         - sx127x.set_mode_rx
         - sx127x.send_packet:
             data: [0xC5, 0x51, 0x78, 0x82, 0xB7, 0xF9, 0x9C, 0x5C]
+        - sx127x.send_packet: !lambda |-
+            return {0x01, 0x02, (uint8_t)id(my_number).state};