From 769923e8dd5880c7d3a82793b40bb4ae039cb95b Mon Sep 17 00:00:00 2001
From: Raman Gupta <7243222+raman325@users.noreply.github.com>
Date: Tue, 13 Apr 2021 08:18:51 -0400
Subject: [PATCH] Raise exception for invalid call to
 DeviceRegistry.async_get_or_create (#49038)

* Raise exception instead of returning None for DeviceRegistry.async_get_or_create

* fix entity_platform logic
---
 homeassistant/exceptions.py              | 15 +++++++++++++++
 homeassistant/helpers/device_registry.py | 12 +++++++++---
 homeassistant/helpers/entity_platform.py | 12 +++++++++---
 tests/helpers/test_device_registry.py    | 20 ++++++++++++--------
 4 files changed, 45 insertions(+), 14 deletions(-)

diff --git a/homeassistant/exceptions.py b/homeassistant/exceptions.py
index fba00e094cd..a081cfe3cc2 100644
--- a/homeassistant/exceptions.py
+++ b/homeassistant/exceptions.py
@@ -183,3 +183,18 @@ class MaxLengthExceeded(HomeAssistantError):
         self.value = value
         self.property_name = property_name
         self.max_length = max_length
+
+
+class RequiredParameterMissing(HomeAssistantError):
+    """Raised when a required parameter is missing from a function call."""
+
+    def __init__(self, parameter_names: list[str]) -> None:
+        """Initialize error."""
+        super().__init__(
+            self,
+            (
+                "Call must include at least one of the following parameters: "
+                f"{', '.join(parameter_names)}"
+            ),
+        )
+        self.parameter_names = parameter_names
diff --git a/homeassistant/helpers/device_registry.py b/homeassistant/helpers/device_registry.py
index e0e5130a94f..80c54ed296f 100644
--- a/homeassistant/helpers/device_registry.py
+++ b/homeassistant/helpers/device_registry.py
@@ -10,6 +10,7 @@ import attr
 
 from homeassistant.const import EVENT_HOMEASSISTANT_STARTED
 from homeassistant.core import Event, HomeAssistant, callback
+from homeassistant.exceptions import RequiredParameterMissing
 from homeassistant.loader import bind_hass
 import homeassistant.util.uuid as uuid_util
 
@@ -259,10 +260,10 @@ class DeviceRegistry:
         # To disable a device if it gets created
         disabled_by: str | None | UndefinedType = UNDEFINED,
         suggested_area: str | None | UndefinedType = UNDEFINED,
-    ) -> DeviceEntry | None:
+    ) -> DeviceEntry:
         """Get device. Create if it doesn't exist."""
         if not identifiers and not connections:
-            return None
+            raise RequiredParameterMissing(["identifiers", "connections"])
 
         if identifiers is None:
             identifiers = set()
@@ -300,7 +301,7 @@ class DeviceRegistry:
         else:
             via_device_id = UNDEFINED
 
-        return self._async_update_device(
+        device = self._async_update_device(
             device.id,
             add_config_entry_id=config_entry_id,
             via_device_id=via_device_id,
@@ -315,6 +316,11 @@ class DeviceRegistry:
             suggested_area=suggested_area,
         )
 
+        # This is safe because _async_update_device will always return a device
+        # in this use case.
+        assert device
+        return device
+
     @callback
     def async_update_device(
         self,
diff --git a/homeassistant/helpers/entity_platform.py b/homeassistant/helpers/entity_platform.py
index 490a5a2298c..25996c81d9d 100644
--- a/homeassistant/helpers/entity_platform.py
+++ b/homeassistant/helpers/entity_platform.py
@@ -24,7 +24,11 @@ from homeassistant.core import (
     split_entity_id,
     valid_entity_id,
 )
-from homeassistant.exceptions import HomeAssistantError, PlatformNotReady
+from homeassistant.exceptions import (
+    HomeAssistantError,
+    PlatformNotReady,
+    RequiredParameterMissing,
+)
 from homeassistant.helpers import (
     config_validation as cv,
     device_registry as dev_reg,
@@ -434,9 +438,11 @@ class EntityPlatform:
                     if key in device_info:
                         processed_dev_info[key] = device_info[key]
 
-                device = device_registry.async_get_or_create(**processed_dev_info)
-                if device:
+                try:
+                    device = device_registry.async_get_or_create(**processed_dev_info)
                     device_id = device.id
+                except RequiredParameterMissing:
+                    pass
 
             disabled_by: str | None = None
             if not entity.entity_registry_enabled_default:
diff --git a/tests/helpers/test_device_registry.py b/tests/helpers/test_device_registry.py
index c5328000269..1a768662fc7 100644
--- a/tests/helpers/test_device_registry.py
+++ b/tests/helpers/test_device_registry.py
@@ -6,6 +6,7 @@ import pytest
 
 from homeassistant.const import EVENT_HOMEASSISTANT_STARTED
 from homeassistant.core import CoreState, callback
+from homeassistant.exceptions import RequiredParameterMissing
 from homeassistant.helpers import device_registry, entity_registry
 
 from tests.common import (
@@ -114,18 +115,21 @@ async def test_requirement_for_identifier_or_connection(registry):
         manufacturer="manufacturer",
         model="model",
     )
-    entry3 = registry.async_get_or_create(
-        config_entry_id="1234",
-        connections=set(),
-        identifiers=set(),
-        manufacturer="manufacturer",
-        model="model",
-    )
 
     assert len(registry.devices) == 2
     assert entry
     assert entry2
-    assert entry3 is None
+
+    with pytest.raises(RequiredParameterMissing) as exc_info:
+        registry.async_get_or_create(
+            config_entry_id="1234",
+            connections=set(),
+            identifiers=set(),
+            manufacturer="manufacturer",
+            model="model",
+        )
+
+    assert exc_info.value.parameter_names == ["identifiers", "connections"]
 
 
 async def test_multiple_config_entries(registry):