修复工作流表删除迁移幂等

backend/alembic/versions/20260116_05_remove_document_workflows.py

@@ -20,10 +20,18 @@ depends_on: Union[str, Sequence[str], None] = None
 
 
 def upgrade() -> None:
-    op.drop_table("workflow_actions")
-    op.drop_table("version_workflows")
-    op.drop_table("workflow_nodes")
-    op.drop_table("workflow_templates")
+    bind = op.get_bind()
+    inspector = sa.inspect(bind)
+    tables = set(inspector.get_table_names())
+
+    if "workflow_actions" in tables:
+        op.drop_table("workflow_actions")
+    if "version_workflows" in tables:
+        op.drop_table("version_workflows")
+    if "workflow_nodes" in tables:
+        op.drop_table("workflow_nodes")
+    if "workflow_templates" in tables:
+        op.drop_table("workflow_templates")
     op.execute("DROP TYPE IF EXISTS workflow_action_type")
     op.execute("DROP TYPE IF EXISTS workflow_status")
 

backend/tests/test_migration_safety.py

@@ -8,6 +8,15 @@ def test_is_locked_migration_is_idempotent():
     assert 'if "is_locked" in columns:' in source
 
 
+def test_removed_workflow_tables_are_dropped_conditionally():
+    source = Path("alembic/versions/20260116_05_remove_document_workflows.py").read_text(encoding="utf-8")
+
+    assert 'if "workflow_actions" in tables:' in source
+    assert 'if "version_workflows" in tables:' in source
+    assert 'if "workflow_nodes" in tables:' in source
+    assert 'if "workflow_templates" in tables:' in source
+
+
 def test_migration_state_check_script_exists():
     source = Path("scripts/check_migration_state.py").read_text(encoding="utf-8")