Avoid trying to import platforms that do not exist (#112028)

* Avoid trying to import platforms that do not exist

* adjust

* fixes

* cleanup

* cleanup

* cleanup

* Apply suggestions from code review

* docs

* fixes

* fixes

* comment

* coverage

* coverage

* coverage

* Switch config to use async_get_component

This was another path where integrations that were marked to load in the executor
would be loaded in the loop

* Switch config to use async_get_component/async_get_platform

This was another path where integrations that were marked to load in the executor
would be loaded in the loop

* merge

* refactor

* refactor

* coverage

* preen

* preen

homeassistant/config.py

@@ -1432,6 +1432,8 @@ async def async_process_component_config(  # noqa: C901
 
     # Check if the integration has a custom config validator
     config_validator = None
+    if integration.platform_exists("config") is not False:
+        # If the config platform cannot possibly exist, don't try to load it.
         try:
             config_validator = await integration.async_get_platform("config")
         except ImportError as err:

homeassistant/helpers/integration_platform.py

@@ -48,6 +48,10 @@ def _get_platform(
         )
         return None
 
+    if integration.platform_exists(platform_name) is False:
+        # If the platform cannot possibly exist, don't bother trying to load it
+        return None
+
     try:
         return integration.get_platform(platform_name)
     except ImportError as err:

homeassistant/loader.py

@@ -12,6 +12,7 @@ from dataclasses import dataclass
 import functools as ft
 import importlib
 import logging
+import os
 import pathlib
 import sys
 import time
@@ -976,6 +977,43 @@ class Integration:
             return platform
         return self._load_platform(platform_name)
 
+    def platform_exists(self, platform_name: str) -> bool | None:
+        """Check if a platform exists for an integration.
+
+        Returns True if the platform exists, False if it does not.
+
+        If it cannot be determined if the platform exists without attempting
+        to import the component, it returns None. This will only happen
+        if this function is called before get_component or async_get_component
+        has been called for the integration or the integration failed to load.
+        """
+        full_name = f"{self.domain}.{platform_name}"
+
+        cache: dict[str, ModuleType] = self.hass.data[DATA_COMPONENTS]
+        if full_name in cache:
+            return True
+
+        missing_platforms_cache: dict[str, ImportError]
+        missing_platforms_cache = self.hass.data[DATA_MISSING_PLATFORMS]
+        if full_name in missing_platforms_cache:
+            return False
+
+        if not (component := cache.get(self.domain)) or not (
+            file := getattr(component, "__file__", None)
+        ):
+            return None
+
+        path: pathlib.Path = pathlib.Path(file).parent.joinpath(platform_name)
+        if os.path.exists(path.with_suffix(".py")) or os.path.exists(path):
+            return True
+
+        exc = ModuleNotFoundError(
+            f"Platform {full_name} not found",
+            name=f"{self.pkg_path}.{platform_name}",
+        )
+        missing_platforms_cache[full_name] = exc
+        return False
+
     def _load_platform(self, platform_name: str) -> ModuleType:
         """Load a platform for an integration.
 

tests/test_loader.py

@@ -1,5 +1,6 @@
 """Test to verify that we can load components."""
 import asyncio
+import os
 import sys
 from typing import Any
 from unittest.mock import MagicMock, Mock, patch
@@ -1193,3 +1194,45 @@ async def test_async_get_platform_raises_after_import_failure(
         in caplog.text
     )
     assert "loaded_executor=False" not in caplog.text
+
+
+async def test_platform_exists(
+    hass: HomeAssistant, enable_custom_integrations: None
+) -> None:
+    """Test platform_exists."""
+    integration = await loader.async_get_integration(hass, "test_integration_platform")
+    assert integration.domain == "test_integration_platform"
+
+    # get_component never called, will return None
+    assert integration.platform_exists("non_existing") is None
+
+    component = integration.get_component()
+    assert component.DOMAIN == "test_integration_platform"
+
+    # component is loaded, should now return False
+    with patch(
+        "homeassistant.loader.os.path.exists", wraps=os.path.exists
+    ) as mock_exists:
+        assert integration.platform_exists("non_existing") is False
+
+    # We should check if the file exists
+    assert mock_exists.call_count == 2
+
+    # component is loaded, should now return False
+    with patch(
+        "homeassistant.loader.os.path.exists", wraps=os.path.exists
+    ) as mock_exists:
+        assert integration.platform_exists("non_existing") is False
+
+    # We should remember the file does not exist
+    assert mock_exists.call_count == 0
+
+    assert integration.platform_exists("group") is True
+
+    platform = await integration.async_get_platform("group")
+    assert platform.MAGIC == 1
+
+    platform = integration.get_platform("group")
+    assert platform.MAGIC == 1
+
+    assert integration.platform_exists("group") is True

tests/testing_config/custom_components/test_integration_platform/__init__.py

@@ -0,0 +1,9 @@
+"""Provide a mock package component."""
+from .const import TEST  # noqa: F401
+
+DOMAIN = "test_integration_platform"
+
+
+async def async_setup(hass, config):
+    """Mock a successful setup."""
+    return True

tests/testing_config/custom_components/test_integration_platform/config_flow.py

@@ -0,0 +1,7 @@
+"""Config flow."""
+
+from homeassistant.core import HomeAssistant
+
+
+async def _async_has_devices(hass: HomeAssistant) -> bool:
+    return True

tests/testing_config/custom_components/test_integration_platform/const.py

@@ -0,0 +1,2 @@
+"""Constants for test_package custom component."""
+TEST = 5

tests/testing_config/custom_components/test_integration_platform/group.py

@@ -0,0 +1,3 @@
+"""Group."""
+
+MAGIC = 1

tests/testing_config/custom_components/test_integration_platform/manifest.json

@@ -0,0 +1,11 @@
+{
+  "domain": "test_integration_platform",
+  "name": "Test Integration Platform",
+  "documentation": "http://test-package.io",
+  "requirements": [],
+  "dependencies": [],
+  "codeowners": [],
+  "config_flow": true,
+  "import_executor": true,
+  "version": "1.2.3"
+}