Fix KeyError in decora setup (#28279)

* Imported homeassistant.util and slugified address if no name is specified

* Added a custom validator function in case name is not set in config

* Removed logger.debug line only used for testing

homeassistant/components/decora/light.py

@@ -1,4 +1,5 @@
 """Support for Decora dimmers."""
+import copy
 from functools import wraps
 import logging
 import time
@@ -15,17 +16,34 @@ from homeassistant.components.light import (
 )
 from homeassistant.const import CONF_API_KEY, CONF_DEVICES, CONF_NAME
 import homeassistant.helpers.config_validation as cv
+import homeassistant.util as util
 
 _LOGGER = logging.getLogger(__name__)
 
 SUPPORT_DECORA_LED = SUPPORT_BRIGHTNESS
 
+
+def _name_validator(config):
+    """Validate the name."""
+    config = copy.deepcopy(config)
+    for address, device_config in config[CONF_DEVICES].items():
+        if CONF_NAME not in device_config:
+            device_config[CONF_NAME] = util.slugify(address)
+
+    return config
+
+
 DEVICE_SCHEMA = vol.Schema(
     {vol.Optional(CONF_NAME): cv.string, vol.Required(CONF_API_KEY): cv.string}
 )
 
-PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
+PLATFORM_SCHEMA = vol.Schema(
+    vol.All(
+        PLATFORM_SCHEMA.extend(
             {vol.Optional(CONF_DEVICES, default={}): {cv.string: DEVICE_SCHEMA}}
+        ),
+        _name_validator,
+    )
 )