From 0db160e37235351877fccb2b39f91566ef58988a Mon Sep 17 00:00:00 2001
From: Jc2k <john.carr@unrouted.co.uk>
Date: Sat, 24 Jul 2021 07:03:44 +0100
Subject: [PATCH] Handle homekit accessories where the pairing flag is wrong
 (#53385)

---
 .../homekit_controller/config_flow.py         | 25 ++++++++-
 .../homekit_controller/test_config_flow.py    | 56 +++++++++++++++++--
 2 files changed, 75 insertions(+), 6 deletions(-)

diff --git a/homeassistant/components/homekit_controller/config_flow.py b/homeassistant/components/homekit_controller/config_flow.py
index e8357a4001d..a19c1d0c107 100644
--- a/homeassistant/components/homekit_controller/config_flow.py
+++ b/homeassistant/components/homekit_controller/config_flow.py
@@ -3,6 +3,7 @@ import logging
 import re
 
 import aiohomekit
+from aiohomekit.exceptions import AuthenticationError
 import voluptuous as vol
 
 from homeassistant import config_entries
@@ -270,7 +271,29 @@ class HomekitControllerFlowHandler(config_entries.ConfigFlow, domain=DOMAIN):
         # invalid. Remove it automatically.
         existing = find_existing_host(self.hass, hkid)
         if not paired and existing:
-            await self.hass.config_entries.async_remove(existing.entry_id)
+            if self.controller is None:
+                await self._async_setup_controller()
+
+            pairing = self.controller.load_pairing(
+                existing.data["AccessoryPairingID"], dict(existing.data)
+            )
+            try:
+                await pairing.list_accessories_and_characteristics()
+                _LOGGER.debug(
+                    "%s (%s - %s) claims to be unpaired but isn't. It's implementation of HomeKit is defective or a zeroconf relay is broadcasting stale data",
+                    name,
+                    model,
+                    hkid,
+                )
+                return self.async_abort(reason="already_paired")
+            except AuthenticationError:
+                _LOGGER.debug(
+                    "%s (%s - %s) is unpaired. Removing invalid pairing for this device",
+                    name,
+                    model,
+                    hkid,
+                )
+                await self.hass.config_entries.async_remove(existing.entry_id)
 
         # Set unique-id and error out if it's already configured
         self._abort_if_unique_id_configured(updates=updated_ip_port)
diff --git a/tests/components/homekit_controller/test_config_flow.py b/tests/components/homekit_controller/test_config_flow.py
index 52685334500..b08659bf77b 100644
--- a/tests/components/homekit_controller/test_config_flow.py
+++ b/tests/components/homekit_controller/test_config_flow.py
@@ -4,6 +4,7 @@ import unittest.mock
 from unittest.mock import AsyncMock, patch
 
 import aiohomekit
+from aiohomekit.exceptions import AuthenticationError
 from aiohomekit.model import Accessories, Accessory
 from aiohomekit.model.characteristics import CharacteristicsTypes
 from aiohomekit.model.services import ServicesTypes
@@ -351,8 +352,48 @@ async def test_discovery_does_not_ignore_non_homekit(hass, controller):
     assert result["type"] == "form"
 
 
+async def test_discovery_broken_pairing_flag(hass, controller):
+    """
+    There is already a config entry for the pairing and its pairing flag is wrong in zeroconf.
+
+    We have seen this particular implementation error in 2 different devices.
+    """
+    await controller.add_paired_device(Accessories(), "00:00:00:00:00:00")
+
+    MockConfigEntry(
+        domain="homekit_controller",
+        data={"AccessoryPairingID": "00:00:00:00:00:00"},
+        unique_id="00:00:00:00:00:00",
+    ).add_to_hass(hass)
+
+    # We just added a mock config entry so it must be visible in hass
+    assert len(hass.config_entries.async_entries()) == 1
+
+    device = setup_mock_accessory(controller)
+    discovery_info = get_device_discovery_info(device)
+
+    # Make sure that we are pairable
+    assert discovery_info["properties"]["sf"] != 0x0
+
+    # Device is discovered
+    result = await hass.config_entries.flow.async_init(
+        "homekit_controller",
+        context={"source": config_entries.SOURCE_ZEROCONF},
+        data=discovery_info,
+    )
+
+    # Should still be paired.
+    config_entry_count = len(hass.config_entries.async_entries())
+    assert config_entry_count == 1
+
+    # Even though discovered as pairable, we bail out as already paired.
+    assert result["reason"] == "already_paired"
+
+
 async def test_discovery_invalid_config_entry(hass, controller):
     """There is already a config entry for the pairing id but it's invalid."""
+    pairing = await controller.add_paired_device(Accessories(), "00:00:00:00:00:00")
+
     MockConfigEntry(
         domain="homekit_controller",
         data={"AccessoryPairingID": "00:00:00:00:00:00"},
@@ -366,11 +407,16 @@ async def test_discovery_invalid_config_entry(hass, controller):
     discovery_info = get_device_discovery_info(device)
 
     # Device is discovered
-    result = await hass.config_entries.flow.async_init(
-        "homekit_controller",
-        context={"source": config_entries.SOURCE_ZEROCONF},
-        data=discovery_info,
-    )
+    with patch.object(
+        pairing,
+        "list_accessories_and_characteristics",
+        side_effect=AuthenticationError("Invalid pairing keys"),
+    ):
+        result = await hass.config_entries.flow.async_init(
+            "homekit_controller",
+            context={"source": config_entries.SOURCE_ZEROCONF},
+            data=discovery_info,
+        )
 
     # Discovery of a HKID that is in a pairable state but for which there is
     # already a config entry - in that case the stale config entry is