Fix kolla-set-configs --check to detect state mismatch

If a configuration file is tracked in the state file
but no longer appears in config.json, it should either be
restored or removed.

This patch introduces a new exception StateMismatch and
updates execute_config_check() to detect such cases. If
any destination path is present in the defaults state but
missing from config.json, we now raise StateMismatch.

A dedicated unit test has been added to verify
this behavior.

Closes-Bug: #2114173

Signed-off-by: Michal Arbet <michal.arbet@ultimum.io>
Change-Id: I6e0b4aaa5722990e3ac647578023f474db3d4381

docker/base/set_configs.py

@@ -68,6 +68,10 @@ class ConfigFileCommandDiffers(ExitingException):
     pass
 
 
+class StateMismatch(ExitingException):
+    pass
+
+
 class ConfigFile(object):
 
     def __init__(self, source, dest, owner=None, perm=None, optional=False,
@@ -583,6 +587,56 @@ def execute_command_check(config):
 
 
 def execute_config_check(config):
+    """Check configuration state consistency and validate config file entries.
+
+    This function compares the current config file destinations from the
+    provided config dictionary with those stored in the defaults state file.
+    If any destinations are found in the state file but not in the config,
+    a StateMismatch exception is raised. These missing files would otherwise
+    be restored or removed depending on their backup state.
+
+    After validating consistency, the function performs standard checks on
+    each declared configuration file, including content, permissions, and
+    ownership validation.
+
+    Args:
+        config (dict): The configuration dictionary containing 'config_files'
+        entries as expected by Kolla.
+
+    Raises:
+        StateMismatch: If there are entries in the defaults state not present
+        in the provided config.
+    """
+    state = get_defaults_state()
+
+    # Build a set of all current destination paths from config.json
+    # If the destination is a directory, we append the
+    # basename of the source
+    current_dests = {
+        entry['dest'] if not entry['dest'].endswith('/') else
+        os.path.join(entry['dest'], os.path.basename(entry['source']))
+        for entry in config.get('config_files', [])
+        if entry.get('dest')
+    }
+
+    # Detect any paths that are present in the state file but
+    # missing from config.json.
+    # These would be either restored (if state[dest] has a backup)
+    # or removed (if dest is null)
+    removed_dests = [
+        path for path in state.keys()
+        if path not in current_dests
+    ]
+
+    if removed_dests:
+        raise StateMismatch(
+            f"The following config files are tracked in state but missing "
+            f"from config.json. "
+            f"They would be restored or removed: {sorted(removed_dests)}"
+        )
+
+    # Perform the regular content, permissions, and ownership
+    # checks on the declared files
     for data in config.get('config_files', []):
         config_file = ConfigFile(**data)
         config_file.check()

releasenotes/notes/bug-2114173-70d0b815a42ae239.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Fixes set_configs.py not detecting removed config files
+    during --check, which prevented container restart when
+    needed. `LP#2114173 <https://launchpad.net/bugs/2114173>`__

tests/test_set_config.py

@@ -892,3 +892,47 @@ class ConfigFileTest(base.BaseTestCase):
 
         # Verify that the updated state was saved
         mock_set_defaults_state.assert_called_once_with(expected_state)
+
+
+class ExecuteConfigCheckStateMismatchTest(base.BaseTestCase):
+
+    @mock.patch.object(set_configs, 'get_defaults_state')
+    def test_execute_config_check_raises_state_mismatch(
+        self, mock_get_defaults_state
+    ):
+        """Test execute_config_check() when state has extra config file.
+
+        This test simulates the scenario where the state file contains
+        a destination that no longer exists in config.json. It verifies:
+        - get_defaults_state() returns a state with an extra entry.
+        - execute_config_check() raises StateMismatch when config.json
+          omits a tracked destination.
+        """
+        config = {
+            "command": "/bin/true",
+            "config_files": [
+                {
+                    "source": "/etc/foo/foo.conf",
+                    "dest": "/etc/foo/foo.conf",
+                    "owner": "user1",
+                    "perm": "0644"
+                }
+            ]
+        }
+
+        mock_get_defaults_state.return_value = {
+            "/etc/foo/foo.conf": {
+                "source": "/etc/foo/foo.conf",
+                "preserve_properties": True,
+                "dest": "/etc/kolla/defaults/etc/foo/foo.conf"
+            },
+            "/etc/old/obsolete.conf": {
+                "source": "/etc/old/obsolete.conf",
+                "preserve_properties": True,
+                "dest": "/etc/kolla/defaults/etc/old/obsolete.conf"
+            }
+        }
+
+        self.assertRaises(set_configs.StateMismatch,
+                          set_configs.execute_config_check,
+                          config)