Endpoint user preview ignores owned knowledge bases in items list

[Marius-brt]

While working on GET /api/v1/users/{user_id}/preview, I noticed a bug where knowledge bases created directly by a user do not show up in their preview items list.

Problem

The endpoint returns an empty knowledge.items array for knowledge bases owned by the target user (knowledge.user_id == user_id), even though knowledge.total counts them.

Root cause:
The endpoint evaluates access exclusively via AccessGrants.get_accessible_resource_ids. Because resource ownership (knowledge.user_id) is stored separately from the access_grants table, owned items are filtered out.

This logic is already properly handled elsewhere in the codebase (e.g., Knowledges.get_knowledge_bases_by_user_id), where it explicitly checks knowledge_base.user_id == user_id before falling back to AccessGrants.has_access.

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Proposed Fix

In backend/open_webui/routers/users.py, update the list comprehension to account for implicit owner access:

# Current implementation
'items': [{'id': k.id, 'name': k.name} for k in all_knowledge if k.id in accessible_knowledge_ids],

# Proposed fix
'items': [{'id': k.id, 'name': k.name} for k in all_knowledge if k.user_id == user_id or k.id in accessible_knowledge_ids],

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Key Takeaways

• No Breaking Changes: Zero impact on the response payload shape or database schema.
• Performance: Negligible; user_id is already in scope and all_knowledge is already queried.
• Scope Note: models and tools in the same endpoint rely on the same check, but knowledge bases are the primary resource affected by direct user ownership.

I have a PR ready for this fix and can submit it right away if approved!

[Marius-brt]

Here is the PR : #27423