Update platform loading path (home-assistant#20807)

* Warn when platform loaded from an entity component folder

* Fix tests

homeassistant/const.py

@@ -7,8 +7,8 @@
 __version__ = '{}.{}'.format(__short_version__, PATCH_VERSION)
 REQUIRED_PYTHON_VER = (3, 5, 3)
 
-# Format for platforms
-PLATFORM_FORMAT = '{domain}.{platform}'
+# Format for platform files
+PLATFORM_FORMAT = '{platform}.{domain}'
 
 # Can be used to specify a catch all when registering state or event listeners.
 MATCH_ALL = '*'

homeassistant/loader.py

@@ -45,9 +45,7 @@ def set_component(hass,  # type: HomeAssistant
 
     Async friendly.
     """
-    cache = hass.data.get(DATA_KEY)
-    if cache is None:
-        cache = hass.data[DATA_KEY] = {}
+    cache = hass.data.setdefault(DATA_KEY, {})
     cache[comp_name] = component
 
 
@@ -60,13 +58,22 @@ def get_platform(hass,  # type: HomeAssistant
     platform = _load_file(hass, PLATFORM_FORMAT.format(
         domain=domain, platform=platform_name))
 
-    if platform is None:
-        # Turn it around for legacy purposes
-        platform = _load_file(hass, PLATFORM_FORMAT.format(
-            domain=platform_name, platform=domain))
+    if platform is not None:
+        return platform
+
+    # Legacy platform check: light/hue.py
+    platform = _load_file(hass, PLATFORM_FORMAT.format(
+        domain=platform_name, platform=domain))
 
     if platform is None:
         _LOGGER.error("Unable to find platform %s", platform_name)
+        return None
+
+    if platform.__name__.startswith(PATH_CUSTOM_COMPONENTS):
+        _LOGGER.warning(
+            "Integrations need to be in their own folder. Change %s/%s.py to "
+            "%s/%s.py. This will stop working soon.",
+            domain, platform_name, platform_name, domain)
 
     return platform
 

tests/common.py

@@ -486,6 +486,8 @@ def __init__(self, domain=None, dependencies=None, setup=None,
 class MockPlatform:
     """Provide a fake platform."""
 
+    __name__ = "homeassistant.components.light.bla"
+
     # pylint: disable=invalid-name
     def __init__(self, setup_platform=None, dependencies=None,
                  platform_schema=None, async_setup_platform=None,

tests/test_loader.py

@@ -132,3 +132,17 @@ async def test_log_warning_custom_component(hass, caplog):
 
     loader.get_component(hass, 'light.test')
     assert 'You are using a custom component for light.test' in caplog.text
+
+
+async def test_get_platform(hass, caplog):
+    """Test get_platform."""
+    # Test we prefer embedded over normal platforms."""
+    embedded_platform = loader.get_platform(hass, 'switch', 'test_embedded')
+    assert embedded_platform.__name__ == \
+        'custom_components.test_embedded.switch'
+
+    caplog.clear()
+
+    legacy_platform = loader.get_platform(hass, 'switch', 'test')
+    assert legacy_platform.__name__ == 'custom_components.switch.test'
+    assert 'Integrations need to be in their own folder.' in caplog.text

tests/testing_config/custom_components/switch/test_embedded.py

@@ -0,0 +1 @@
+"""Test switch platform for test_embedded component."""