From 1bbc1f5f55de29bef86edbf7e504298c3d51bdc8 Mon Sep 17 00:00:00 2001
From: Paulus Schoutsen <balloob@gmail.com>
Date: Fri, 18 Feb 2022 16:11:17 -0800
Subject: [PATCH] Validate in split_entity_id (#66835)

---
 homeassistant/components/logbook/__init__.py |  4 ++--
 homeassistant/core.py                        |  7 +++++--
 tests/helpers/test_entity_registry.py        | 18 +++++++++---------
 tests/test_core.py                           | 12 +++++++++++-
 4 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/homeassistant/components/logbook/__init__.py b/homeassistant/components/logbook/__init__.py
index 1af10039772..28b0460ac7a 100644
--- a/homeassistant/components/logbook/__init__.py
+++ b/homeassistant/components/logbook/__init__.py
@@ -71,7 +71,7 @@ GROUP_BY_MINUTES = 15
 EMPTY_JSON_OBJECT = "{}"
 UNIT_OF_MEASUREMENT_JSON = '"unit_of_measurement":'
 
-HA_DOMAIN_ENTITY_ID = f"{HA_DOMAIN}."
+HA_DOMAIN_ENTITY_ID = f"{HA_DOMAIN}._"
 
 CONFIG_SCHEMA = vol.Schema(
     {DOMAIN: INCLUDE_EXCLUDE_BASE_FILTER_SCHEMA}, extra=vol.ALLOW_EXTRA
@@ -598,7 +598,7 @@ def _keep_event(hass, event, entities_filter):
     if domain is None:
         return False
 
-    return entities_filter is None or entities_filter(f"{domain}.")
+    return entities_filter is None or entities_filter(f"{domain}._")
 
 
 def _augment_data_with_context(
diff --git a/homeassistant/core.py b/homeassistant/core.py
index 38a0bbeb73c..27dba3cbc52 100644
--- a/homeassistant/core.py
+++ b/homeassistant/core.py
@@ -141,9 +141,12 @@ TIMEOUT_EVENT_START = 15
 _LOGGER = logging.getLogger(__name__)
 
 
-def split_entity_id(entity_id: str) -> list[str]:
+def split_entity_id(entity_id: str) -> tuple[str, str]:
     """Split a state entity ID into domain and object ID."""
-    return entity_id.split(".", 1)
+    domain, _, object_id = entity_id.partition(".")
+    if not domain or not object_id:
+        raise ValueError(f"Invalid entity ID {entity_id}")
+    return domain, object_id
 
 
 VALID_ENTITY_ID = re.compile(r"^(?!.+__)(?!_)[\da-z_]+(?<!_)\.(?!_)[\da-z_]+(?<!_)$")
diff --git a/tests/helpers/test_entity_registry.py b/tests/helpers/test_entity_registry.py
index 78c99640bd0..bad19bf78cb 100644
--- a/tests/helpers/test_entity_registry.py
+++ b/tests/helpers/test_entity_registry.py
@@ -1220,9 +1220,9 @@ def test_entity_registry_items():
 async def test_deprecated_disabled_by_str(hass, registry, caplog):
     """Test deprecated str use of disabled_by converts to enum and logs a warning."""
     entry = registry.async_get_or_create(
-        "light",
-        "hue",
-        "5678",
+        domain="light.kitchen",
+        platform="hue",
+        unique_id="5678",
         disabled_by=er.RegistryEntryDisabler.USER.value,
     )
 
@@ -1233,9 +1233,9 @@ async def test_deprecated_disabled_by_str(hass, registry, caplog):
 async def test_deprecated_entity_category_str(hass, registry, caplog):
     """Test deprecated str use of entity_category converts to enum and logs a warning."""
     entry = er.RegistryEntry(
-        "light",
-        "hue",
-        "5678",
+        entity_id="light.kitchen",
+        unique_id="5678",
+        platform="hue",
         entity_category="diagnostic",
     )
 
@@ -1246,9 +1246,9 @@ async def test_deprecated_entity_category_str(hass, registry, caplog):
 async def test_invalid_entity_category_str(hass, registry, caplog):
     """Test use of invalid entity category."""
     entry = er.RegistryEntry(
-        "light",
-        "hue",
-        "5678",
+        entity_id="light.kitchen",
+        unique_id="5678",
+        platform="hue",
         entity_category="invalid",
     )
 
diff --git a/tests/test_core.py b/tests/test_core.py
index afb5f507044..e052b08ecca 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -49,7 +49,17 @@ PST = dt_util.get_time_zone("America/Los_Angeles")
 
 def test_split_entity_id():
     """Test split_entity_id."""
-    assert ha.split_entity_id("domain.object_id") == ["domain", "object_id"]
+    assert ha.split_entity_id("domain.object_id") == ("domain", "object_id")
+    with pytest.raises(ValueError):
+        ha.split_entity_id("")
+    with pytest.raises(ValueError):
+        ha.split_entity_id(".")
+    with pytest.raises(ValueError):
+        ha.split_entity_id("just_domain")
+    with pytest.raises(ValueError):
+        ha.split_entity_id("empty_object_id.")
+    with pytest.raises(ValueError):
+        ha.split_entity_id(".empty_domain")
 
 
 def test_async_add_hass_job_schedule_callback():