Fix readonly database error in reset_memories (#3753)

[devin-ai-integration]

Fix readonly database error in reset_memories (#3753)

Summary

Fixes issue #3753 where calling crew.reset_memories(command_type='all') fails with "attempt to write a readonly database" error when trying to reset agent knowledge.

The fix adds error handling to gracefully ignore "readonly database" and "collection does not exist" errors during memory reset operations. These errors indicate the collection is already in a reset state (either inaccessible or already deleted), so they can be safely ignored. This approach follows the existing pattern in RAGStorage.reset() which already handles these same errors.

Changes made:

• Added try-except error handling in KnowledgeStorage.reset() to catch and ignore readonly database and collection not found errors
• Added similar error handling in Crew.reset_knowledge() to handle cases where the error propagates from the Knowledge layer
• Added 5 comprehensive tests covering various reset scenarios (all memories, agent knowledge, crew knowledge, with different error types)

Review & Testing Checklist for Human

⚠️ Risk Level: YELLOW - Changes work but have some fragility concerns

• Verify string matching approach: The fix uses string matching ("attempt to write a readonly database" in str(e)) to identify specific errors. Confirm this is robust enough for production use, especially if ChromaDB/Qdrant error messages change
• Test with actual readonly database: The unit tests use mocks. Test the fix with a real scenario where:
  • Database file has incorrect permissions (chmod 444)
  • Multiple processes access the database simultaneously
  • Database is locked by another process
• Verify silent error handling is correct: The fix silently ignores these errors. Confirm this is the desired behavior vs. logging a warning to help users debug permission issues
• Review dual error handling: Error handling was added in both KnowledgeStorage.reset() and Crew.reset_knowledge(). Consider if both layers are necessary or if one would suffice

Test Plan

# 1. Run the new tests
uv run pytest lib/crewai/tests/test_crew_reset_memories_readonly.py -xvs

# 2. Run existing error handling tests
uv run pytest lib/crewai/tests/rag/test_error_handling.py -xvs

# 3. Run existing crew reset memory tests
uv run pytest lib/crewai/tests/test_crew.py -k "reset" -xvs

# 4. Test end-to-end with a real readonly database (manual):
# - Create a crew with agent knowledge
# - Make the ChromaDB database file readonly (chmod 444)
# - Call crew.reset_memories(command_type='all')
# - Verify no exception is raised

Notes

• All existing tests pass ✅
• The fix follows the existing error handling pattern in RAGStorage.reset()
• Existing test test_knowledge_storage_reset_readonly_database in test_error_handling.py already expected this behavior
• The issue description ([BUG]Failed to reset all memory:Failed to reset Agent Knowledge memory: attempt to write a readonly database #3753) only provided an error message without reproduction steps, so the fix is based on error message analysis and existing code patterns

Session Info: Requested by João (joao@crewai.com)
Devin Session: https://app.devin.ai/sessions/2b34f161b21e4823bcecb446eb4c5fa6

[devin-ai-integration]

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