fix: skip empty knowledge-base embedding batches (#6106)

Co-authored-by: stablegenius49 <185121704+stablegenius49@users.noreply.github.com>

astrbot/core/db/vec_db/faiss_impl/vec_db.py

@@ -74,6 +74,10 @@ class FaissVecDB(BaseVecDB):
         metadatas = metadatas or [{} for _ in contents]
         ids = ids or [str(uuid.uuid4()) for _ in contents]
 
+        if not contents:
+            logger.debug("No contents provided for batch insert; skipping embedding generation.")
+            return []
+
         start = time.time()
         logger.debug(f"Generating embeddings for {len(contents)} contents...")
         vectors = await self.embedding_provider.get_embeddings_batch(

tests/unit/test_faiss_vec_db.py

@@ -0,0 +1,20 @@
+from unittest.mock import AsyncMock
+
+import pytest
+
+from astrbot.core.db.vec_db.faiss_impl.vec_db import FaissVecDB
+
+
+@pytest.mark.asyncio
+async def test_insert_batch_skips_empty_contents() -> None:
+    vec_db = FaissVecDB.__new__(FaissVecDB)
+    vec_db.embedding_provider = AsyncMock()
+    vec_db.document_storage = AsyncMock()
+    vec_db.embedding_storage = AsyncMock()
+
+    result = await FaissVecDB.insert_batch(vec_db, [])
+
+    assert result == []
+    vec_db.embedding_provider.get_embeddings_batch.assert_not_awaited()
+    vec_db.document_storage.insert_documents_batch.assert_not_awaited()
+    vec_db.embedding_storage.insert_batch.assert_not_awaited()