Dispose replaced migration database handles

tests/test_module_system.py

@@ -2040,6 +2040,25 @@ finally:
         self.assertEqual(["check", "verify"], [record["task_id"] for record in records])
         self.assertEqual(["warning", "warning"], [record["status"] for record in records])
 
+    def test_registered_module_migration_tasks_dispose_replaced_database(self) -> None:
+        root = Path(tempfile.mkdtemp(prefix="govoplan-module-migration-dispose-", dir=_TEST_ROOT))
+        previous = configure_database(f"sqlite:///{root / 'previous.db'}")
+        previous_pool = previous.engine.pool
+        manifest = ModuleManifest(id="taskmod", name="Task Module", version="1.0.0")
+
+        try:
+            run_registered_module_migration_tasks(
+                database_url=f"sqlite:///{root / 'target.db'}",
+                enabled_modules=("taskmod",),
+                phases=(),
+                manifest_factories=(lambda: manifest,),
+            )
+
+            self.assertIsNot(previous.engine.pool, previous_pool)
+            self.assertEqual(f"sqlite:///{root / 'target.db'}", get_database().database_url)
+        finally:
+            reset_database(dispose=True)
+
     def test_module_installer_preflight_blocks_provider_update_that_breaks_installed_consumer(self) -> None:
         available = {
             "files": ModuleManifest(