From d17ffff3e3524e75fa29ff2efbf26bae05fb7443 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 27 Aug 2023 12:00:39 -0500
Subject: [PATCH] Retry tplink setup later if device has an unexpected mac
 address (#98784)

Retry tplink setup later if device has an unexpected serial

If the DHCP reservation changed and there is now a different tplink device at
the saved IP address, retry setup later to avoid cross linking devices
---
 homeassistant/components/tplink/__init__.py | 14 ++++++++++++-
 tests/components/tplink/test_init.py        | 22 +++++++++++++++++++++
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/homeassistant/components/tplink/__init__.py b/homeassistant/components/tplink/__init__.py
index 2edea30835f..d8285cbed70 100644
--- a/homeassistant/components/tplink/__init__.py
+++ b/homeassistant/components/tplink/__init__.py
@@ -85,11 +85,23 @@ async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
 
 async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     """Set up TPLink from a config entry."""
+    host = entry.data[CONF_HOST]
     try:
-        device: SmartDevice = await Discover.discover_single(entry.data[CONF_HOST])
+        device: SmartDevice = await Discover.discover_single(host)
     except SmartDeviceException as ex:
         raise ConfigEntryNotReady from ex
 
+    found_mac = dr.format_mac(device.mac)
+    if found_mac != entry.unique_id:
+        # If the mac address of the device does not match the unique_id
+        # of the config entry, it likely means the DHCP lease has expired
+        # and the device has been assigned a new IP address. We need to
+        # wait for the next discovery to find the device at its new address
+        # and update the config entry so we do not mix up devices.
+        raise ConfigEntryNotReady(
+            f"Unexpected device found at {host}; expected {entry.unique_id}, found {found_mac}"
+        )
+
     hass.data[DOMAIN][entry.entry_id] = TPLinkDataUpdateCoordinator(hass, device)
     await hass.config_entries.async_forward_entry_setups(entry, PLATFORMS)
 
diff --git a/tests/components/tplink/test_init.py b/tests/components/tplink/test_init.py
index 0354549d451..4206c0de6ad 100644
--- a/tests/components/tplink/test_init.py
+++ b/tests/components/tplink/test_init.py
@@ -4,6 +4,8 @@ from __future__ import annotations
 from datetime import timedelta
 from unittest.mock import MagicMock, patch
 
+import pytest
+
 from homeassistant import setup
 from homeassistant.components import tplink
 from homeassistant.components.tplink.const import DOMAIN
@@ -111,3 +113,23 @@ async def test_dimmer_switch_unique_id_fix_original_entity_still_exists(
     )
     assert migrated_dimmer_entity_reg.entity_id == original_dimmer_entity_reg.entity_id
     assert migrated_dimmer_entity_reg.entity_id != rollout_dimmer_entity_reg.entity_id
+
+
+async def test_config_entry_wrong_mac_Address(
+    hass: HomeAssistant, caplog: pytest.LogCaptureFixture
+) -> None:
+    """Test config entry enters setup retry when mac address mismatches."""
+    mismatched_mac = f"{MAC_ADDRESS[:-1]}0"
+    already_migrated_config_entry = MockConfigEntry(
+        domain=DOMAIN, data={CONF_HOST: "127.0.0.1"}, unique_id=mismatched_mac
+    )
+    already_migrated_config_entry.add_to_hass(hass)
+    with _patch_discovery(), _patch_single_discovery():
+        await async_setup_component(hass, tplink.DOMAIN, {tplink.DOMAIN: {}})
+        await hass.async_block_till_done()
+        assert already_migrated_config_entry.state == ConfigEntryState.SETUP_RETRY
+
+    assert (
+        "Unexpected device found at 127.0.0.1; expected aa:bb:cc:dd:ee:f0, found aa:bb:cc:dd:ee:ff"
+        in caplog.text
+    )