Handle invalid utf-8 from the ESPHome dashboard (#95743)

If the yaml file has invalid utf-8, the config flow would raise an
unhandled exception. Allow the encryption key to be entered manually
in this case instead of a hard failure

fixes #92772

homeassistant/components/esphome/config_flow.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 
 from collections import OrderedDict
 from collections.abc import Mapping
+import json
 import logging
 from typing import Any
 
@@ -408,6 +409,11 @@ class EsphomeFlowHandler(ConfigFlow, domain=DOMAIN):
         except aiohttp.ClientError as err:
             _LOGGER.error("Error talking to the dashboard: %s", err)
             return False
+        except json.JSONDecodeError as err:
+            _LOGGER.error(
+                "Error parsing response from dashboard: %s", err, exc_info=True
+            )
+            return False
 
         self._noise_psk = noise_psk
         return True

tests/components/esphome/test_config_flow.py

@@ -1,5 +1,6 @@
 """Test config flow."""
 import asyncio
+import json
 from unittest.mock import AsyncMock, MagicMock, patch
 
 from aioesphomeapi import (
@@ -414,8 +415,13 @@ async def test_user_discovers_name_and_gets_key_from_dashboard(
     assert mock_client.noise_psk == VALID_NOISE_PSK
 
 
+@pytest.mark.parametrize(
+    "dashboard_exception",
+    [aiohttp.ClientError(), json.JSONDecodeError("test", "test", 0)],
+)
 async def test_user_discovers_name_and_gets_key_from_dashboard_fails(
     hass: HomeAssistant,
+    dashboard_exception: Exception,
     mock_client,
     mock_dashboard,
     mock_zeroconf: None,
@@ -442,7 +448,7 @@ async def test_user_discovers_name_and_gets_key_from_dashboard_fails(
 
     with patch(
         "homeassistant.components.esphome.dashboard.ESPHomeDashboardAPI.get_encryption_key",
-        side_effect=aiohttp.ClientError,
+        side_effect=dashboard_exception,
     ):
         result = await hass.config_entries.flow.async_init(
             "esphome",