Always set up after dependencies if they are scheduled to be loaded (#141593)

* Always setup after dependencies

* Add comment

homeassistant/setup.py

@@ -213,17 +213,24 @@ async def _async_process_dependencies(
         if dep not in hass.config.components
     }
 
-    after_dependencies_tasks: dict[str, asyncio.Future[bool]] = {}
     to_be_loaded = hass.data.get(DATA_SETUP_DONE, {})
+    # We don't want to just wait for the futures from `to_be_loaded` here.
+    # We want to ensure that our after_dependencies are always actually
+    # scheduled to be set up, as if for whatever reason they had not been,
+    # we would deadlock waiting for them here.
     for dep in integration.after_dependencies:
         if (
             dep not in dependencies_tasks
             and dep in to_be_loaded
             and dep not in hass.config.components
         ):
-            after_dependencies_tasks[dep] = to_be_loaded[dep]
+            dependencies_tasks[dep] = setup_futures.get(dep) or create_eager_task(
+                async_setup_component(hass, dep, config),
+                name=f"setup {dep} as after dependency of {integration.domain}",
+                loop=hass.loop,
+            )
 
-    if not dependencies_tasks and not after_dependencies_tasks:
+    if not dependencies_tasks:
         return []
 
     if dependencies_tasks:
@@ -232,17 +239,9 @@ async def _async_process_dependencies(
             integration.domain,
             dependencies_tasks.keys(),
         )
-    if after_dependencies_tasks:
-        _LOGGER.debug(
-            "Dependency %s will wait for after dependencies %s",
-            integration.domain,
-            after_dependencies_tasks.keys(),
-        )
 
     async with hass.timeout.async_freeze(integration.domain):
-        results = await asyncio.gather(
+        results = await asyncio.gather(*dependencies_tasks.values())
-            *dependencies_tasks.values(), *after_dependencies_tasks.values()
-        )
 
     failed = [
         domain for idx, domain in enumerate(dependencies_tasks) if not results[idx]

tests/test_setup.py

@@ -458,6 +458,29 @@ async def test_set_domains_to_be_loaded(hass: HomeAssistant) -> None:
     assert not hass.data[setup.DATA_SETUP_DONE]
 
 
+async def test_component_setup_after_dependencies(hass: HomeAssistant) -> None:
+    """Test that after dependencies are set up before the component."""
+    mock_integration(hass, MockModule("dep"))
+    mock_integration(
+        hass, MockModule("comp", partial_manifest={"after_dependencies": ["dep"]})
+    )
+    mock_integration(
+        hass, MockModule("comp2", partial_manifest={"after_dependencies": ["dep"]})
+    )
+
+    setup.async_set_domains_to_be_loaded(hass, {"comp"})
+
+    assert await setup.async_setup_component(hass, "comp", {})
+    assert "comp" in hass.config.components
+    assert "dep" not in hass.config.components
+
+    setup.async_set_domains_to_be_loaded(hass, {"comp2", "dep"})
+
+    assert await setup.async_setup_component(hass, "comp2", {})
+    assert "comp2" in hass.config.components
+    assert "dep" in hass.config.components
+
+
 async def test_component_setup_with_validation_and_dependency(
     hass: HomeAssistant,
 ) -> None: