[core] Combine set_component_source_ + register_component_ into one call (#16029)

esphome/core/application.h

@@ -382,7 +382,11 @@ class Application {
 
   /// Register a component, detecting loop() override at compile time.
   /// Uses HasLoopOverride<T> which handles ambiguous &T::loop from multiple inheritance.
-  template<typename T> void register_component_(T *comp) {
+  /// Optionally sets the component source index in the same call to avoid emitting
+  /// a separate set_component_source_() line in generated code.
+  template<typename T> void register_component_(T *comp, uint8_t source_index = 0) {
+    if (source_index != 0)
+      comp->set_component_source_(source_index);
     this->register_component_impl_(comp, HasLoopOverride<T>::value);
   }
 

esphome/cpp_helpers.py

@@ -197,9 +197,9 @@ async def register_component(var, config):
         )
     if name is not None:
         idx = register_component_source(name)
-        add(var.set_component_source_(idx))
-
-    add(App.register_component_(var))
+        add(App.register_component_(var, idx))
+    else:
+        add(App.register_component_(var))
 
     # Collect C++ type for compile-time looping component count
     comp_entries = CORE.data.setdefault("looping_component_entries", [])

tests/component_tests/deep_sleep/test_deep_sleep.py

@@ -12,7 +12,7 @@ def test_deep_sleep_setup(generate_main):
         in main_cpp
     )
     assert "new(deepsleep) deep_sleep::DeepSleepComponent();" in main_cpp
-    assert "App.register_component_(deepsleep);" in main_cpp
+    assert "App.register_component_(deepsleep, " in main_cpp
 
 
 def test_deep_sleep_sleep_duration(generate_main):

tests/component_tests/ota/test_web_server_ota.py

@@ -27,7 +27,7 @@ def test_web_server_ota_generated(generate_main: Callable[[str], str]) -> None:
     assert "global_web_server_base" in main_cpp
 
     # Check component is registered
-    assert "App.register_component_(web_server_webserverotacomponent_id)" in main_cpp
+    assert "App.register_component_(web_server_webserverotacomponent_id" in main_cpp
 
 
 def test_web_server_ota_with_callbacks(generate_main: Callable[[str], str]) -> None:

tests/unit_tests/test_cpp_helpers.py

@@ -34,8 +34,9 @@ async def test_register_component(monkeypatch):
     actual = await ch.register_component(var, {})
 
     assert actual is var
-    assert add_mock.call_count == 2
-    app_mock.register_component_.assert_called_with(var)
+    assert add_mock.call_count == 1
+    app_mock.register_component_.assert_called_once()
+    assert app_mock.register_component_.call_args.args[0] is var
     assert core_mock.component_ids == []
 
 
@@ -77,8 +78,9 @@ async def test_register_component__with_setup_priority(monkeypatch):
 
     assert actual is var
     add_mock.assert_called()
-    assert add_mock.call_count == 4
-    app_mock.register_component_.assert_called_with(var)
+    assert add_mock.call_count == 3
+    app_mock.register_component_.assert_called_once()
+    assert app_mock.register_component_.call_args.args[0] is var
     assert core_mock.component_ids == []