From 3b458738e08225a351f41a0152402779809a83e4 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sat, 26 Oct 2024 03:29:15 -1000
Subject: [PATCH] Fix setting brightness to 0 in HomeKit when the On
 characteristic is not sent (#129201)

---
 .../components/homekit/type_lights.py          |  8 ++++++--
 tests/components/homekit/test_type_lights.py   | 18 ++++++++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/homeassistant/components/homekit/type_lights.py b/homeassistant/components/homekit/type_lights.py
index 6b57a03153c..cde80178c5e 100644
--- a/homeassistant/components/homekit/type_lights.py
+++ b/homeassistant/components/homekit/type_lights.py
@@ -171,8 +171,9 @@ class Light(HomeAccessory):
         events = []
         service = SERVICE_TURN_ON
         params: dict[str, Any] = {ATTR_ENTITY_ID: self.entity_id}
+        has_on = CHAR_ON in char_values
 
-        if CHAR_ON in char_values:
+        if has_on:
             if not char_values[CHAR_ON]:
                 service = SERVICE_TURN_OFF
             events.append(f"Set state to {char_values[CHAR_ON]}")
@@ -180,7 +181,10 @@ class Light(HomeAccessory):
         brightness_pct = None
         if CHAR_BRIGHTNESS in char_values:
             if char_values[CHAR_BRIGHTNESS] == 0:
-                events[-1] = "Set state to 0"
+                if has_on:
+                    events[-1] = "Set state to 0"
+                else:
+                    events.append("Set state to 0")
                 service = SERVICE_TURN_OFF
             else:
                 brightness_pct = char_values[CHAR_BRIGHTNESS]
diff --git a/tests/components/homekit/test_type_lights.py b/tests/components/homekit/test_type_lights.py
index d365165aca4..a45e4988c36 100644
--- a/tests/components/homekit/test_type_lights.py
+++ b/tests/components/homekit/test_type_lights.py
@@ -226,6 +226,24 @@ async def test_light_brightness(
     assert len(events) == 3
     assert events[-1].data[ATTR_VALUE] == f"Set state to 0, brightness at 0{PERCENTAGE}"
 
+    hk_driver.set_characteristics(
+        {
+            HAP_REPR_CHARS: [
+                {
+                    HAP_REPR_AID: acc.aid,
+                    HAP_REPR_IID: char_brightness_iid,
+                    HAP_REPR_VALUE: 0,
+                },
+            ]
+        },
+        "mock_addr",
+    )
+    await _wait_for_light_coalesce(hass)
+    assert call_turn_off
+    assert call_turn_off[0].data[ATTR_ENTITY_ID] == entity_id
+    assert len(events) == 4
+    assert events[-1].data[ATTR_VALUE] == f"Set state to 0, brightness at 0{PERCENTAGE}"
+
     # 0 is a special case for homekit, see "Handle Brightness"
     # in update_state
     hass.states.async_set(