- pinecone_store: call self.index.describe_index_stats() instead of the
nonexistent self.describe_index_stats(), and use a unit query vector
instead of an all-zero vector so filter_by_metadata() works on
cosine-metric indexes (the library's own default)
- pgvector_store: apply the existing lowercase true/false bool handling
to the list-filter branch too, and use the jsonb ?| operator so
list-valued metadata fields match on intersection instead of being
compared as a single JSON-text blob
- sqlite_vec_store: use json_each() with a json_type guard so list-valued
metadata fields match on intersection, mirroring the in-memory
backend's set-intersection semantics
- faiss_store: filter_by_metadata(limit=0) now returns [] instead of one
result
- milvus_store: reject NaN/Infinity filter values up front with a clear
ValidationError instead of building an invalid expression that gets
silently swallowed
- update the #848 FAISS NotImplementedError test to reflect that FAISS
now implements real filter_by_metadata() (this PR's whole point)
- add regression tests for each fix; sqlite tests run against the real
sqlite-vec extension