fix: coordinate vector migration with concurrent searches and note saves

backend/app/services/coordination.py

@@ -1,7 +1,14 @@
 import asyncio
 from functools import wraps
+from weakref import WeakKeyDictionary
 
-_vault_mutation_lock = asyncio.Lock()
+_vault_locks = WeakKeyDictionary()
+
+
+def vault_mutation_lock():
+    # Service/test lifecycle restarts must not reuse a lock bound to a closed loop.
+    loop = asyncio.get_running_loop()
+    return _vault_locks.setdefault(loop, asyncio.Lock())
 
 
 def serialized_vault_mutation(operation):
@@ -9,7 +16,7 @@ def serialized_vault_mutation(operation):
 
     @wraps(operation)
     async def wrapped(*args, **kwargs):
-        async with _vault_mutation_lock:
+        async with vault_mutation_lock():
             return await operation(*args, **kwargs)
 
     return wrapped

backend/app/services/index_service.py

@@ -17,7 +17,7 @@ from app.errors import ApiError
 from app.knowledge.parser import parse_note
 from app.services.note_service import index_note, prepare_note_index
 from app.database.db import connect, transaction
-from app.services.coordination import _vault_mutation_lock
+from app.services.coordination import vault_mutation_lock
 from app.retrieval.vectorstore import SqliteVecStore
 from app.local_models.runtime import LocalEmbedding
 from app.services import note_service
@@ -116,7 +116,7 @@ async def rebuild(request: IndexRebuildRequest) -> IndexJob:
             prepared_notes.append((parsed, prepared))
         # All network/model awaits precede the transaction. The concrete SQLite
         # methods below complete synchronously despite their async interfaces.
-        async with _vault_mutation_lock:
+        async with vault_mutation_lock():
             if _scan_vault() != docs or saved_records != {key: repository.get_note_record(key) for key in _pending_notes()}:
                 raise ApiError(409, "INDEX_SNAPSHOT_CHANGED", "笔记在计算期间发生变化，稍后重新计算。")
             conn = connect()
@@ -263,7 +263,7 @@ async def _refresh_saved_note(note_id: str) -> None:
         prepared = await prepare_note_index(parsed, strict=True)
         if isinstance(note_service.embedding, LocalEmbedding) and parsed.blocks and prepared[1] is None:
             raise ApiError(503, "EMBEDDING_UNAVAILABLE", "笔记已保存，后台向量计算未完成。")
-        async with _vault_mutation_lock:
+        async with vault_mutation_lock():
             current = repository.get_note_record(note_id)
             if current != record or note_service._read_markdown(record.file_path) != markdown:
                 # Another save or rename won the race; leave the durable queue entry intact.