Warn instead of raise on duplicate YAML key (#8834)

* Warn instead of raise on duplicate key

* Update test_yaml.py

* Lint

* Change to error

homeassistant/util/yaml.py

@@ -185,12 +185,9 @@ def _ordered_dict(loader: SafeLineLoader,
 
         if key in seen:
             fname = getattr(loader.stream, 'name', '')
-            first_mark = yaml.Mark(fname, 0, seen[key], -1, None, None)
-            second_mark = yaml.Mark(fname, 0, line, -1, None, None)
-            raise yaml.MarkedYAMLError(
-                context="duplicate key: \"{}\"".format(key),
-                context_mark=first_mark, problem_mark=second_mark,
-            )
+            _LOGGER.error(
+                'YAML file %s contains duplicate key "%s". '
+                'Check lines %d and %d.', fname, key, seen[key], line)
         seen[key] = line
 
     return _add_reference(OrderedDict(nodes), loader, node)

tests/util/test_yaml.py

@@ -5,12 +5,22 @@ import unittest
 import logging
 from unittest.mock import patch
 
+import pytest
+
 from homeassistant.exceptions import HomeAssistantError
 from homeassistant.util import yaml
 from homeassistant.config import YAML_CONFIG_FILE, load_yaml_config_file
 from tests.common import get_test_config_dir, patch_yaml_files
 
 
+@pytest.fixture(autouse=True)
+def mock_credstash():
+    """Mock credstash so it doesn't connect to the internet."""
+    with patch.object(yaml, 'credstash') as mock_credstash:
+        mock_credstash.getSecret.return_value = None
+        yield mock_credstash
+
+
 class TestYaml(unittest.TestCase):
     """Test util.yaml loader."""
 
@@ -30,13 +40,6 @@ class TestYaml(unittest.TestCase):
             doc = yaml.yaml.safe_load(file)
         assert doc['key'] == 'value'
 
-    def test_duplicate_key(self):
-        """Test duplicate dict keys."""
-        files = {YAML_CONFIG_FILE: 'key: thing1\nkey: thing2'}
-        with self.assertRaises(HomeAssistantError):
-            with patch_yaml_files(files):
-                load_yaml_config_file(YAML_CONFIG_FILE)
-
     def test_unhashable_key(self):
         """Test an unhasable key."""
         files = {YAML_CONFIG_FILE: 'message:\n  {{ states.state }}'}
@@ -411,3 +414,11 @@ def test_representing_yaml_loaded_data():
     with patch_yaml_files(files):
         data = load_yaml_config_file(YAML_CONFIG_FILE)
     assert yaml.dump(data) == "key:\n- 1\n- '2'\n- 3\n"
+
+
+def test_duplicate_key(caplog):
+    """Test duplicate dict keys."""
+    files = {YAML_CONFIG_FILE: 'key: thing1\nkey: thing2'}
+    with patch_yaml_files(files):
+        load_yaml_config_file(YAML_CONFIG_FILE)
+    assert 'contains duplicate key' in caplog.text