fix(database): harden fresh migration chain compatibility (#6278)

database/versions/e6a1c4b8d2f0_2_2_13.py

@@ -36,55 +36,87 @@ def _has_column(
     )
 
 
+def _has_index(
+    inspector: sa.Inspector,
+    table_name: str,
+    index_name: str,
+) -> bool:
+    """检查数据表是否已存在指定索引。"""
+    if table_name not in inspector.get_table_names():
+        return False
+    return any(
+        index["name"] == index_name
+        for index in inspector.get_indexes(table_name)
+    )
+
+
+def _column_names(inspector: sa.Inspector, table_name: str) -> set[str]:
+    """读取数据表当前全部字段名。"""
+    if table_name not in inspector.get_table_names():
+        return set()
+    return {
+        column["name"]
+        for column in inspector.get_columns(table_name)
+    }
+
+
+def _ensure_column_and_index(column_name: str) -> None:
+    """独立补齐整理历史的规范身份字段及其索引。"""
+    table_name = "transferhistory"
+    index_name = f"ix_{table_name}_{column_name}"
+    inspector = sa.inspect(op.get_bind())
+    if not _has_column(inspector, table_name, column_name):
+        op.add_column(
+            table_name,
+            sa.Column(column_name, sa.String(), nullable=True),
+        )
+
+    inspector = sa.inspect(op.get_bind())
+    if not _has_index(inspector, table_name, index_name):
+        op.create_index(index_name, table_name, [column_name])
+
+
 def upgrade() -> None:
     """升级整理历史数据源字段。"""
-    inspector = sa.inspect(op.get_bind())
-    if not _has_column(inspector, "transferhistory", "media_source"):
-        op.add_column(
-            "transferhistory",
-            sa.Column("media_source", sa.String(), nullable=True),
-        )
-        op.create_index(
-            "ix_transferhistory_media_source",
-            "transferhistory",
-            ["media_source"],
-        )
+    _ensure_column_and_index("media_source")
+    _ensure_column_and_index("media_id")
 
-    inspector = sa.inspect(op.get_bind())
-    if not _has_column(inspector, "transferhistory", "media_id"):
-        op.add_column(
-            "transferhistory",
-            sa.Column("media_id", sa.String(), nullable=True),
-        )
-        op.create_index(
-            "ix_transferhistory_media_id",
-            "transferhistory",
-            ["media_id"],
-        )
-
-    transfer_history = sa.table(
-        "transferhistory",
-        sa.column("tmdbid", sa.Integer()),
-        sa.column("doubanid", sa.String()),
+    columns = _column_names(sa.inspect(op.get_bind()), "transferhistory")
+    table_columns = [
         sa.column("media_source", sa.String()),
         sa.column("media_id", sa.String()),
-    )
+    ]
+    if "tmdbid" in columns:
+        table_columns.append(sa.column("tmdbid", sa.Integer()))
+    if "doubanid" in columns:
+        table_columns.append(sa.column("doubanid", sa.String()))
+    transfer_history = sa.table("transferhistory", *table_columns)
     connection = op.get_bind()
-    connection.execute(
-        transfer_history.update()
-        .where(transfer_history.c.tmdbid.is_not(None))
-        .where(transfer_history.c.media_id.is_(None))
-        .values(
-            media_source="themoviedb",
-            media_id=sa.cast(transfer_history.c.tmdbid, sa.String()),
+
+    if "tmdbid" in columns:
+        connection.execute(
+            transfer_history.update()
+            .where(transfer_history.c.tmdbid.is_not(None))
+            .where(transfer_history.c.media_id.is_(None))
+            .values(
+                media_source="themoviedb",
+                media_id=sa.cast(transfer_history.c.tmdbid, sa.String()),
+            )
         )
-    )
-    connection.execute(
+
+    if "doubanid" not in columns:
+        return
+    douban_update = (
         transfer_history.update()
-        .where(transfer_history.c.tmdbid.is_(None))
         .where(transfer_history.c.doubanid.is_not(None))
         .where(transfer_history.c.media_id.is_(None))
-        .values(
+    )
+    if "tmdbid" in columns:
+        douban_update = douban_update.where(
+            transfer_history.c.tmdbid.is_(None)
+        )
+    connection.execute(
+        douban_update.values(
             media_source="douban",
             media_id=transfer_history.c.doubanid,
         )
@@ -93,15 +125,12 @@ def upgrade() -> None:
 
 def downgrade() -> None:
     """回滚整理历史数据源字段。"""
-    inspector = sa.inspect(op.get_bind())
-    if _has_column(inspector, "transferhistory", "media_id"):
-        op.drop_index("ix_transferhistory_media_id", table_name="transferhistory")
-        op.drop_column("transferhistory", "media_id")
+    for column_name in ("media_id", "media_source"):
+        index_name = f"ix_transferhistory_{column_name}"
+        inspector = sa.inspect(op.get_bind())
+        if _has_index(inspector, "transferhistory", index_name):
+            op.drop_index(index_name, table_name="transferhistory")
 
-    inspector = sa.inspect(op.get_bind())
-    if _has_column(inspector, "transferhistory", "media_source"):
-        op.drop_index(
-            "ix_transferhistory_media_source",
-            table_name="transferhistory",
-        )
-        op.drop_column("transferhistory", "media_source")
+        inspector = sa.inspect(op.get_bind())
+        if _has_column(inspector, "transferhistory", column_name):
+            op.drop_column("transferhistory", column_name)