Refactor recorder migration (#80175)

* Refactor recorder migration

* Improve test coverage

homeassistant/components/recorder/migration.py

@@ -3,6 +3,7 @@ from __future__ import annotations
 
 from collections.abc import Callable, Iterable
 import contextlib
+from dataclasses import dataclass
 from datetime import timedelta
 import logging
 from typing import TYPE_CHECKING, cast
@@ -61,33 +62,65 @@ def raise_if_exception_missing_str(ex: Exception, match_substrs: Iterable[str])
     raise ex
 
 
-def get_schema_version(session_maker: Callable[[], Session]) -> int:
+def get_schema_version(session_maker: Callable[[], Session]) -> int | None:
     """Get the schema version."""
-    with session_scope(session=session_maker()) as session:
-        res = (
-            session.query(SchemaChanges)
-            .order_by(SchemaChanges.change_id.desc())
-            .first()
-        )
-        current_version = getattr(res, "schema_version", None)
-
-        if current_version is None:
-            current_version = _inspect_schema_version(session)
-            _LOGGER.debug(
-                "No schema version found. Inspected version: %s", current_version
+    try:
+        with session_scope(session=session_maker()) as session:
+            res = (
+                session.query(SchemaChanges)
+                .order_by(SchemaChanges.change_id.desc())
+                .first()
             )
+            current_version = getattr(res, "schema_version", None)
 
-        return cast(int, current_version)
+            if current_version is None:
+                current_version = _inspect_schema_version(session)
+                _LOGGER.debug(
+                    "No schema version found. Inspected version: %s", current_version
+                )
+
+            return cast(int, current_version)
+    except Exception as err:  # pylint: disable=broad-except
+        _LOGGER.exception("Error when determining DB schema version: %s", err)
+        return None
 
 
-def schema_is_current(current_version: int) -> bool:
+@dataclass
+class SchemaValidationStatus:
+    """Store schema validation status."""
+
+    current_version: int
+
+
+def _schema_is_current(current_version: int) -> bool:
     """Check if the schema is current."""
     return current_version == SCHEMA_VERSION
 
 
-def live_migration(current_version: int) -> bool:
+def schema_is_valid(schema_status: SchemaValidationStatus) -> bool:
+    """Check if the schema is valid."""
+    return _schema_is_current(schema_status.current_version)
+
+
+def validate_db_schema(
+    hass: HomeAssistant, session_maker: Callable[[], Session]
+) -> SchemaValidationStatus | None:
+    """Check if the schema is valid.
+
+    This checks that the schema is the current version as well as for some common schema
+    errors caused by manual migration between database engines, for example importing an
+    SQLite database to MariaDB.
+    """
+    current_version = get_schema_version(session_maker)
+    if current_version is None:
+        return None
+
+    return SchemaValidationStatus(current_version)
+
+
+def live_migration(schema_status: SchemaValidationStatus) -> bool:
     """Check if live migration is possible."""
-    return current_version >= LIVE_MIGRATION_MIN_SCHEMA_VERSION
+    return schema_status.current_version >= LIVE_MIGRATION_MIN_SCHEMA_VERSION
 
 
 def migrate_schema(
@@ -95,13 +128,14 @@ def migrate_schema(
     hass: HomeAssistant,
     engine: Engine,
     session_maker: Callable[[], Session],
-    current_version: int,
+    schema_status: SchemaValidationStatus,
 ) -> None:
     """Check if the schema needs to be upgraded."""
+    current_version = schema_status.current_version
     _LOGGER.warning("Database is about to upgrade. Schema version: %s", current_version)
     db_ready = False
     for version in range(current_version, SCHEMA_VERSION):
-        if live_migration(version) and not db_ready:
+        if live_migration(SchemaValidationStatus(version)) and not db_ready:
             db_ready = True
             instance.migration_is_live = True
             hass.add_job(instance.async_set_db_ready)