Avoid falling back to event loop import on ModuleNotFound (#115404)

homeassistant/loader.py

@@ -976,6 +976,8 @@ class Integration:
                 comp = await self.hass.async_add_import_executor_job(
                     self._get_component, True
                 )
+            except ModuleNotFoundError:
+                raise
             except ImportError as ex:
                 load_executor = False
                 _LOGGER.debug(
@@ -1115,6 +1117,8 @@ class Integration:
                                 self._load_platforms, platform_names
                             )
                         )
+                    except ModuleNotFoundError:
+                        raise
                     except ImportError as ex:
                         _LOGGER.debug(
                             "Failed to import %s platforms %s in executor",

tests/test_loader.py

@@ -1471,6 +1471,50 @@ async def test_async_get_component_deadlock_fallback(
     assert module is module_mock
 
 
+async def test_async_get_component_deadlock_fallback_module_not_found(
+    hass: HomeAssistant, caplog: pytest.LogCaptureFixture
+) -> None:
+    """Verify async_get_component fallback behavior.
+
+    Ensure that fallback is not triggered on ModuleNotFoundError.
+    """
+    executor_import_integration = _get_test_integration(
+        hass, "executor_import", True, import_executor=True
+    )
+    assert executor_import_integration.import_executor is True
+    module_mock = MagicMock(__file__="__init__.py")
+    import_attempts = 0
+
+    def mock_import(module: str, *args: Any, **kwargs: Any) -> Any:
+        nonlocal import_attempts
+        if module == "homeassistant.components.executor_import":
+            import_attempts += 1
+
+        if import_attempts == 1:
+            raise ModuleNotFoundError(
+                "homeassistant.components.executor_import not found",
+                name="homeassistant.components.executor_import",
+            )
+
+        return module_mock
+
+    assert "homeassistant.components.executor_import" not in sys.modules
+    assert "custom_components.executor_import" not in sys.modules
+    with (
+        patch("homeassistant.loader.importlib.import_module", mock_import),
+        pytest.raises(
+            ModuleNotFoundError, match="homeassistant.components.executor_import"
+        ),
+    ):
+        await executor_import_integration.async_get_component()
+
+    # We should not have tried to fall back to the event loop import
+    assert "loaded_executor=False" not in caplog.text
+    assert "homeassistant.components.executor_import" not in sys.modules
+    assert "custom_components.executor_import" not in sys.modules
+    assert import_attempts == 1
+
+
 async def test_async_get_component_raises_after_import_failure(
     hass: HomeAssistant, caplog: pytest.LogCaptureFixture
 ) -> None:
@@ -1551,6 +1595,52 @@ async def test_async_get_platform_deadlock_fallback(
     assert module is module_mock
 
 
+async def test_async_get_platform_deadlock_fallback_module_not_found(
+    hass: HomeAssistant, caplog: pytest.LogCaptureFixture
+) -> None:
+    """Verify async_get_platform fallback behavior.
+
+    Ensure that fallback is not triggered on ModuleNotFoundError.
+    """
+    executor_import_integration = _get_test_integration(
+        hass, "executor_import", True, import_executor=True
+    )
+    assert executor_import_integration.import_executor is True
+    module_mock = MagicMock()
+    import_attempts = 0
+
+    def mock_import(module: str, *args: Any, **kwargs: Any) -> Any:
+        nonlocal import_attempts
+        if module == "homeassistant.components.executor_import.config_flow":
+            import_attempts += 1
+
+        if import_attempts == 1:
+            raise ModuleNotFoundError(
+                "Not found homeassistant.components.executor_import.config_flow",
+                name="homeassistant.components.executor_import.config_flow",
+            )
+
+        return module_mock
+
+    assert "homeassistant.components.executor_import" not in sys.modules
+    assert "custom_components.executor_import" not in sys.modules
+    with (
+        patch("homeassistant.loader.importlib.import_module", mock_import),
+        pytest.raises(
+            ModuleNotFoundError,
+            match="homeassistant.components.executor_import.config_flow",
+        ),
+    ):
+        await executor_import_integration.async_get_platform("config_flow")
+
+    # We should not have tried to fall back to the event loop import
+    assert "executor=['config_flow']" in caplog.text
+    assert "loop=['config_flow']" not in caplog.text
+    assert "homeassistant.components.executor_import" not in sys.modules
+    assert "custom_components.executor_import" not in sys.modules
+    assert import_attempts == 1
+
+
 async def test_async_get_platform_raises_after_import_failure(
     hass: HomeAssistant, caplog: pytest.LogCaptureFixture
 ) -> None: