The vector index has always been strictly per-user: every Qdrant payload
carries a `user_id` and the search filter is `user_id == querying_user`.
A file Alice indexed cannot be discovered by Bob even if she has shared
it with him — Bob would have to re-index it under his own user_id to
make it searchable, which means duplicate index entries for every share
recipient.
Switch to ownership-with-ACL-expansion:
- New `nextcloud_mcp_server.search.access_filter` module:
- `list_accessible_owners(sharing_client, user_id)` calls the OCS
Sharing API (`shared_with_me=true`) and returns
`{user_id} ∪ {uid_owner of each share}`. Fails open to `[user_id]`
so a misbehaving Sharing API doesn't black-hole search.
- `build_ownership_filter(user_id, accessible_owners)` returns a
Qdrant `Filter` whose `should` branch matches either the new
`owner_id IN accessible_owners` field or the legacy `user_id` field.
The legacy branch keeps points indexed before this change reachable
without a migration backfill.
- Indexer payload (`vector/processor.py`) now writes `owner_id` alongside
`user_id`. `DocumentTask` gains an optional `owner_id` field; today the
scanner always runs as the owner so the processor falls back to
`user_id`, but the field is plumbed so a future shared-with-me crawler
can set the true owner without reshaping the payload contract.
- `SemanticSearchAlgorithm.search` and `BM25HybridSearchAlgorithm.search`
accept `accessible_owners` via kwargs and use the new ownership filter.
Default behaviour with no kwarg is unchanged (self-only).
- Both user-facing callers — the MCP tool path (`server/semantic.py`) and
the visualization Starlette route (`auth/viz_routes.py`) — compute
`accessible_owners` from the authenticated Nextcloud client before
invoking the search algorithm. Eviction, scanner deletion, placeholder,
and chunk-context paths intentionally keep the legacy `user_id`
semantics (those are "operations on a specific user's records", not
cross-user reads).
- 10 new unit tests in `tests/unit/search/test_access_filter.py` cover
self-only default, owner expansion, dedup, fallback fields, OCS
failure, and the legacy `should`-branch shape.
Pairs with cbcoutinho/astrolabe#89 — together they let an Astrolabe user
find content owners have shared with them without going through any
re-authorization flow or re-indexing.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
