Ensure setup loads top level component before platforms (#112057)

homeassistant/setup.py

@@ -482,8 +482,21 @@ async def async_prepare_setup_platform(
         log_error(str(err))
         return None
 
+    # Platforms cannot exist on their own, they are part of their integration.
+    # If the integration is not set up yet, and can be set up, set it up.
+    #
+    # We do this before we import the platform so the platform already knows
+    # where the top level component is.
+    #
+    if load_top_level_component := integration.domain not in hass.config.components:
+        try:
+            component = await integration.async_get_component()
+        except ImportError as exc:
+            log_error(f"Unable to import the component ({exc}).")
+            return None
+
     try:
-        platform = integration.get_platform(domain)
+        platform = await integration.async_get_platform(domain)
     except ImportError as exc:
         log_error(f"Platform not found ({exc}).")
         return None
@@ -494,13 +507,7 @@ async def async_prepare_setup_platform(
 
     # Platforms cannot exist on their own, they are part of their integration.
     # If the integration is not set up yet, and can be set up, set it up.
-    if integration.domain not in hass.config.components:
-        try:
-            component = integration.get_component()
-        except ImportError as exc:
-            log_error(f"Unable to import the component ({exc}).")
-            return None
-
+    if load_top_level_component:
         if (
             hasattr(component, "setup") or hasattr(component, "async_setup")
         ) and not await async_setup_component(hass, integration.domain, hass_config):

tests/test_setup.py

@@ -7,7 +7,7 @@ from unittest.mock import AsyncMock, Mock, patch
 import pytest
 import voluptuous as vol
 
-from homeassistant import config_entries, setup
+from homeassistant import config_entries, loader, setup
 from homeassistant.const import EVENT_COMPONENT_LOADED, EVENT_HOMEASSISTANT_START
 from homeassistant.core import HomeAssistant, callback
 from homeassistant.exceptions import HomeAssistantError
@@ -822,3 +822,30 @@ async def test_importing_integration_in_executor(
     assert await setup.async_setup_component(hass, "test_package_loaded_executor", {})
     assert await setup.async_setup_component(hass, "test_package_loaded_executor", {})
     await hass.async_block_till_done()
+
+
+async def test_async_prepare_setup_platform(
+    hass: HomeAssistant,
+    enable_custom_integrations: None,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """Test we can prepare a platform setup."""
+    integration = await loader.async_get_integration(hass, "test")
+    with patch.object(
+        integration, "async_get_component", side_effect=ImportError("test is broken")
+    ):
+        assert (
+            await setup.async_prepare_setup_platform(hass, {}, "config", "test") is None
+        )
+
+    assert "test is broken" in caplog.text
+
+    caplog.clear()
+    # There is no actual config platform for this integration
+    assert await setup.async_prepare_setup_platform(hass, {}, "config", "test") is None
+    assert "No module named 'custom_components.test.config'" in caplog.text
+
+    button_platform = (
+        await setup.async_prepare_setup_platform(hass, {}, "button", "test") is None
+    )
+    assert button_platform is not None