Prevent a single accessory setup failure from breaking all HomeKit accessories (#34263)

* Prevent a single accessory setup failure from breaking all HomeKit accessories

Raise the max devices to 150 as the spec allows for this
many.  Previously 100 made sense because of the event
storms when homekit started would sometimes break pairing,
as these have largely been fixed in 0.109 (still a few
to cleanup) using the HAP spec limit of 150 is now possible.

* Handle both failure states

homeassistant/components/homekit/__init__.py

@@ -67,7 +67,7 @@ from .util import (
 
 _LOGGER = logging.getLogger(__name__)
 
-MAX_DEVICES = 100
+MAX_DEVICES = 150
 TYPES = Registry()
 
 # #### Driver Status ####
@@ -361,9 +361,17 @@ class HomeKit:
             return
         aid = generate_aid(state.entity_id)
         conf = self._config.pop(state.entity_id, {})
+        # If an accessory cannot be created or added due to an exception
+        # of any kind (usually in pyhap) it should not prevent
+        # the rest of the accessories from being created
+        try:
             acc = get_accessory(self.hass, self.driver, state, aid, conf)
             if acc is not None:
                 self.bridge.add_accessory(acc)
+        except Exception:  # pylint: disable=broad-except
+            _LOGGER.exception(
+                "Failed to create a HomeKit accessory for %s", state.entity_id
+            )
 
     def remove_bridge_accessory(self, aid):
         """Try adding accessory to bridge if configured beforehand."""

tests/components/homekit/test_homekit.py

@@ -309,6 +309,39 @@ async def test_homekit_start(hass, hk_driver, debounce_patcher):
     assert not hk_driver_start.called
 
 
+async def test_homekit_start_with_a_broken_accessory(hass, hk_driver, debounce_patcher):
+    """Test HomeKit start method."""
+    pin = b"123-45-678"
+    entity_filter = generate_filter(["cover", "light"], ["demo.test"], [], [])
+
+    homekit = HomeKit(hass, None, None, None, entity_filter, {}, None, None)
+    homekit.bridge = Mock()
+    homekit.bridge.accessories = []
+    homekit.driver = hk_driver
+
+    hass.states.async_set("light.demo", "on")
+    hass.states.async_set("light.broken", "on")
+
+    with patch(f"{PATH_HOMEKIT}.get_accessory", side_effect=Exception), patch(
+        f"{PATH_HOMEKIT}.show_setup_message"
+    ) as mock_setup_msg, patch(
+        "pyhap.accessory_driver.AccessoryDriver.add_accessory",
+    ) as hk_driver_add_acc, patch(
+        "pyhap.accessory_driver.AccessoryDriver.start"
+    ) as hk_driver_start:
+        await hass.async_add_executor_job(homekit.start)
+
+    mock_setup_msg.assert_called_with(hass, pin)
+    hk_driver_add_acc.assert_called_with(homekit.bridge)
+    assert hk_driver_start.called
+    assert homekit.status == STATUS_RUNNING
+
+    # Test start() if already started
+    hk_driver_start.reset_mock()
+    await hass.async_add_executor_job(homekit.start)
+    assert not hk_driver_start.called
+
+
 async def test_homekit_stop(hass):
     """Test HomeKit stop method."""
     homekit = HomeKit(hass, None, None, None, None, None, None)