[core] Make the generated apply function a template argument of ApplyAction and ApplyCondition (#19655)

tests/components/http_request/http_request.yaml

@@ -53,8 +53,8 @@ esphome:
               # Regression test for esphome/esphome#16224: a light.turn_on action
               # nested inside on_response with capture_response: true puts
               # `std::string &` into the trigger's Ts..., which exposed a codegen
-              # bug where the apply lambda's parameter list did not match the
-              # ApplyFn signature.
+              # bug where the generated function's parameter list did not match
+              # the automation's arguments.
               - light.turn_on:
                   id: test_regression_light
                   brightness: 100%

tests/unit_tests/test_automation.py

@@ -509,6 +509,8 @@ class MockCodegen(NamedTuple):
     get_variable: AsyncMock
     new_pvariable: MagicMock
     register_parented: AsyncMock
+    add_global: MagicMock
+    calls: MagicMock  # new_pvariable and add_global attached, to check their order
 
 
 @pytest.fixture
@@ -520,10 +522,16 @@ def mock_cg() -> Generator[MockCodegen]:
         patch(
             "esphome.codegen.register_parented", new_callable=AsyncMock
         ) as register_parented,
+        patch("esphome.cpp_generator.add_global") as add_global,
     ):
         get_variable.return_value = PARENT_OBJ
         new_pvariable.return_value = NEW_OBJ
-        yield MockCodegen(get_variable, new_pvariable, register_parented)
+        calls = MagicMock()
+        calls.attach_mock(new_pvariable, "new_pvariable")
+        calls.attach_mock(add_global, "add_global")
+        yield MockCodegen(
+            get_variable, new_pvariable, register_parented, add_global, calls
+        )
 
 
 @pytest.fixture
@@ -649,8 +657,8 @@ async def _run_apply_condition(
     return await _run_entry(conditions["my.check"], config, args, platform, id_key)
 
 
-def _apply_lambda(mock_cg: MockCodegen) -> str:
-    return str(mock_cg.new_pvariable.call_args.args[2])
+def _apply_definition(mock_cg: MockCodegen) -> str:
+    return str(mock_cg.add_global.call_args.args[0])
 
 
 @pytest.mark.asyncio
@@ -661,9 +669,14 @@ async def test_register_apply_action_entry(
     assert entry.type_id is ApplyAction
     assert entry.synchronous is True
     mock_cg.get_variable.assert_awaited_once_with(PARENT_ID)
-    action_id, template_arg, _ = mock_cg.new_pvariable.call_args.args
+    action_id, template_arg = mock_cg.new_pvariable.call_args.args
     assert action_id == ID("obj_1")
-    assert str(template_arg) == "<int32_t>"
+    assert str(template_arg) == "<esphome__obj_1__fn, int32_t>"
+    # The definition must precede the storage line that names the function.
+    assert [c[0] for c in mock_cg.calls.mock_calls] == ["add_global", "new_pvariable"]
+    assert _apply_definition(mock_cg).startswith(
+        "static void esphome__obj_1__fn(const std::remove_cvref_t<int32_t> & x) {"
+    )
 
 
 @pytest.mark.asyncio
@@ -692,7 +705,7 @@ async def test_apply_constants(
     )
     config = {"kp": 0.0, "on": False, "song": "a:b", "position": 0.5}
     await _run_apply_action(registries, fields, config)
-    text = _apply_lambda(mock_cg)
+    text = _apply_definition(mock_cg)
     lines = [
         f"::{PARENT_OBJ}->set_kp(0.0f);",
         f"::{PARENT_OBJ}->set_on(false);",
@@ -715,7 +728,9 @@ async def test_apply_id_constant_is_the_named_object(
     fields = (ApplyField("target", "switch_to_output", cg.RawExpression("Speaker *")),)
     await _run_apply_action(registries, fields, {"target": ID("speaker_b")})
     mock_cg.get_variable.assert_any_await(ID("speaker_b"))
-    assert f"::{PARENT_OBJ}->switch_to_output(::speaker_b);" in _apply_lambda(mock_cg)
+    assert f"::{PARENT_OBJ}->switch_to_output(::speaker_b);" in str(
+        _apply_definition(mock_cg)
+    )
 
 
 @pytest.mark.asyncio
@@ -728,7 +743,9 @@ async def test_apply_condition_id_constant_is_the_named_object(
     check = ApplyCall("is_output({})", (("target", cg.RawExpression("Speaker *")),))
     await _run_apply_condition(registries, check, {"target": ID("speaker_b")})
     mock_cg.get_variable.assert_any_await(ID("speaker_b"))
-    assert f"return ::{PARENT_OBJ}->is_output(::speaker_b);" in _apply_lambda(mock_cg)
+    assert f"return ::{PARENT_OBJ}->is_output(::speaker_b);" in str(
+        _apply_definition(mock_cg)
+    )
 
 
 @pytest.mark.asyncio
@@ -745,8 +762,10 @@ async def test_apply_lambdas(
         "ki": Lambda("if (x) return 1.0f;\nreturn 2.0f;"),
     }
     await _run_apply_action(registries, fields, config, args=[(cg.int32, "x")])
-    text = _apply_lambda(mock_cg)
-    assert text.startswith("[](const std::remove_cvref_t<int32_t> & x) -> void {")
+    text = _apply_definition(mock_cg)
+    assert text.startswith(
+        "static void esphome__obj_1__fn(const std::remove_cvref_t<int32_t> & x) {"
+    )
     # The parent is global-scope qualified, so an arg named like the id cannot shadow it.
     assert f"::{PARENT_OBJ}->set_kp(" in text
     assert f"::{PARENT_OBJ}->set_kp(static_cast<float>(x * 2));" in text
@@ -768,11 +787,11 @@ async def test_apply_call_keys(
         ApplyCall("set_range({}, {})", (("low", cg.float_), ("high", cg.float_))),
     )
     await _run_apply_action(registries, fields, {"low": 1.0, "high": 2.0})
-    assert f"::{PARENT_OBJ}->set_range(1.0f, 2.0f);" in _apply_lambda(mock_cg)
+    assert f"::{PARENT_OBJ}->set_range(1.0f, 2.0f);" in _apply_definition(mock_cg)
 
     mock_cg.new_pvariable.reset_mock()
     await _run_apply_action(registries, fields, {})
-    assert "set_range" not in _apply_lambda(mock_cg)
+    assert "set_range" not in _apply_definition(mock_cg)
 
     with pytest.raises(EsphomeError, match="needs all of"):
         await _run_apply_action(registries, fields, {"low": 1.0})
@@ -784,7 +803,7 @@ async def test_apply_action_call_shape(
 ) -> None:
     fields = (ApplyField("brightness", "set_brightness", cg.float_),)
     await _run_apply_action(registries, fields, {"brightness": 0.5}, call="make_call")
-    text = _apply_lambda(mock_cg)
+    text = _apply_definition(mock_cg)
     lines = [
         f"auto apply_call = ::{PARENT_OBJ}->make_call();",
         "apply_call.set_brightness(0.5f);",
@@ -814,7 +833,7 @@ async def test_apply_field_nested_key_const_fn_and_type_string(
         "value": Lambda("return 42;"),
     }
     await _run_apply_action(registries, fields, config)
-    text = _apply_lambda(mock_cg)
+    text = _apply_definition(mock_cg)
     assert f"::{PARENT_OBJ}->set_direction(3);" in text
     assert f'::{PARENT_OBJ}->set_name("abc", 3);' in text
     assert (
@@ -824,7 +843,7 @@ async def test_apply_field_nested_key_const_fn_and_type_string(
 
     mock_cg.new_pvariable.reset_mock()
     await _run_apply_action(registries, fields[:1], {})
-    assert "set_direction" not in _apply_lambda(mock_cg)
+    assert "set_direction" not in _apply_definition(mock_cg)
 
 
 def test_apply_registration_checks(registries: tuple[Registry, Registry]) -> None:
@@ -883,8 +902,9 @@ async def test_apply_string_constant_stays_in_flash_on_esp8266(
 ) -> None:
     fields = (ApplyField("song", "play", cg.std_string),)
     await _run_apply_action(registries, fields, {"song": "a:b"}, platform="esp8266")
-    assert f'::{PARENT_OBJ}->play(progmem_string(ESPHOME_F("a:b")));' in _apply_lambda(
-        mock_cg
+    assert (
+        f'::{PARENT_OBJ}->play(progmem_string(ESPHOME_F("a:b")));'
+        in _apply_definition(mock_cg)
     )
 
 
@@ -900,7 +920,7 @@ async def test_apply_literal_with_length_is_plain_on_every_platform(
     await _run_apply_action(
         registries, fields, {"option": "h\u00e9llo"}, platform=platform
     )
-    text = _apply_lambda(mock_cg)
+    text = _apply_definition(mock_cg)
     assert f'::{PARENT_OBJ}->set_option("h\\303\\251llo", 6);' in text
     assert "progmem_string" not in text
 
@@ -913,11 +933,13 @@ async def test_register_apply_condition_predicate(
         registries, "is_playing()", {}, args=[(cg.int32, "x")]
     )
     assert entry.type_id is ApplyCondition
-    condition_id, template_arg, check = mock_cg.new_pvariable.call_args.args
+    condition_id, template_arg = mock_cg.new_pvariable.call_args.args
     assert condition_id == ID("obj_1")
-    assert str(template_arg) == "<int32_t>"
-    text = str(check)
-    assert text.startswith("[](const std::remove_cvref_t<int32_t> & x) -> bool {")
+    assert str(template_arg) == "<esphome__obj_1__fn, int32_t>"
+    text = _apply_definition(mock_cg)
+    assert text.startswith(
+        "static bool esphome__obj_1__fn(const std::remove_cvref_t<int32_t> & x) {"
+    )
     assert f"return ::{PARENT_OBJ}->is_playing();" in text
 
 
@@ -927,7 +949,7 @@ async def test_apply_condition_compares_config_value(
 ) -> None:
     check = ApplyCall("state == {}", (("state", cg.bool_),))
     await _run_apply_condition(registries, check, {"state": True})
-    assert f"return ::{PARENT_OBJ}->state == true;" in _apply_lambda(mock_cg)
+    assert f"return ::{PARENT_OBJ}->state == true;" in _apply_definition(mock_cg)
 
     with pytest.raises(EsphomeError, match="needs all of"):
         await _run_apply_condition(registries, check, {})
@@ -940,7 +962,7 @@ async def test_apply_condition_string_constant_is_a_plain_literal(
 ) -> None:
     check = ApplyCall("state == {}", (("state", cg.std_string),))
     await _run_apply_condition(registries, check, {"state": "two"}, platform=platform)
-    assert f'return ::{PARENT_OBJ}->state == "two";' in _apply_lambda(mock_cg)
+    assert f'return ::{PARENT_OBJ}->state == "two";' in _apply_definition(mock_cg)
 
 
 @pytest.mark.asyncio
@@ -964,6 +986,6 @@ async def test_apply_condition_string_lambda_paths(
     await _run_apply_condition(
         registries, check, {"state": Lambda(body)}, args=[(cg.std_string, "x")]
     )
-    text = _apply_lambda(mock_cg)
+    text = _apply_definition(mock_cg)
     assert expected in text
     assert ("-> std::string {" in text) is called