fix(memory): drain pending saves before forget() deletes records by bunnysayzz · Pull Request #7291 · crewAIInc/crewAI

bunnysayzz · 2026-09-05T20:54:16Z

Root cause

forget() in unified_memory.py (line 818) calls self._storage.delete() without first draining the pending-save queue:

# line 844 — no write barrier
return self._storage.delete(
    scope_prefix=effective_scope,
    ...
)

recall() already has the correct barrier at line 713:

# Read barrier: wait for any pending background saves to finish
self.drain_writes()

A remember_many() background save submitted before forget() is called can land after the delete, resurrecting the forgotten content. The race is:

remember_many() submits a background save to _save_pool
Caller calls forget() — delete runs immediately, content gone
Background save completes — content is back in storage
recall() returns the "forgotten" content

Fix

Add self.drain_writes() at the top of forget(), before the scope resolution, mirroring recall(). One line.

Tests

Three regression tests in lib/crewai/tests/memory/test_memory_forget_drain.py:

test_forget_drains_pending_saves_before_delete — verifies drain_writes() precedes _storage.delete() in forget()
test_recall_already_has_drain_writes — regression guard confirming recall() still has its barrier
test_forget_drain_ordering_matches_recall — both methods have consistent write-barrier semantics

All 3 pass with the fix, all 3 fail on the unpatched code.

Fixes #7290

coderabbitai · 2026-09-05T20:55:38Z

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lib/crewai/tests/memory/test_memory_forget_drain.py

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📝 Walkthrough

Walkthrough

Memory.forget() now holds _reset_lock while it drains pending writes and deletes records. Regression tests verify write-barrier ordering, lock coverage, and consistency with recall().

Changes

Memory forget write barrier

Layer / File(s)	Summary
Drain writes before forgetting `lib/crewai/src/crewai/memory/unified_memory.py`, `lib/crewai/tests/memory/test_memory_forget_drain.py`	`Memory.forget()` holds `_reset_lock` across `drain_writes()`, scope calculation, and storage deletion. Tests verify call ordering, lock coverage, and the existing `recall()` barrier.

Sequence Diagram(s)

sequenceDiagram
  participant Caller
  participant MemoryForget
  participant BackgroundSave
  participant Storage
  Caller->>MemoryForget: call forget()
  MemoryForget->>MemoryForget: acquire _reset_lock
  MemoryForget->>BackgroundSave: drain_writes()
  MemoryForget->>Storage: delete records
  MemoryForget-->>Caller: return deleted count

Merge Risk: ⚪ Minimal · up to 9c61c

Memory forgetting now waits for pending saves while coordinating deletion, preventing forgotten records from being restored by delayed writes. No current merge-blocking risk is identified.

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Linked Issues check	⚠️ Warning	The pull request fixes the `forget()` race by draining pending saves while holding `_reset_lock` through deletion, which satisfies the issue's primary `forget()` objective. The linked issue also ident…	Implement equivalent drain and `_reset_lock` coordination in `update()`, or split the `update()` requirement into a separate issue and clarify that this pull request addresses only `forget()`. Add regression coverage for the selected scope.
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 12 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly describes the primary change: draining pending saves before `forget()` deletes records.
Description check	✅ Passed	The description explains the root cause, fix, and regression tests, and links issue `#7290`. It does not use every template heading and contains outdated details, such as stating that the fix is one lin…
Out of Scope Changes check	✅ Passed	The implementation and regression tests directly support the linked issue and the pull request objectives. No unrelated code changes are shown.

Full details: Linked Issues check

Explanation

The pull request fixes the forget() race by draining pending saves while holding _reset_lock through deletion, which satisfies the issue's primary forget() objective. The linked issue also identifies update() as requiring equivalent write-barrier coordination, but this pull request does not modify update().

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Inline comments:
In `@lib/crewai/src/crewai/memory/unified_memory.py`:
- Line 841: Serialize forget() with save submission by holding _reset_lock
across both drain_writes() and _storage.delete(), matching the locking behavior
already used by reset(). Add a deterministic concurrency test that forces
_submit_save() to interleave after drain_writes() snapshots pending saves and
verifies deletion cannot be followed by recreation.

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Inline comments:
In `@lib/crewai/tests/memory/test_memory_forget_drain.py`:
- Around line 86-96: Extend the test around the existing fake_delete helper to
also mock the drain_writes callback with the same helper-thread probe of
mem._reset_lock. Record the drain probe result separately, invoke the drain path
during the test, and assert that neither the deletion probe nor the drain probe
acquires the lock.

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`forget()` called `self._storage.delete()` without first draining the pending-save queue, so a `remember_many()` background save submitted before `forget()` could land after the delete and resurrect the forgotten content. `recall()` already has the correct write barrier (`self.drain_writes()` at line 713); this adds the same barrier to `forget()` before the scope resolution. Adds three regression tests in `tests/memory/test_memory_forget_drain.py` that verify `drain_writes()` is called before `_storage.delete()` in `forget()`, and that the ordering matches `recall()`. Fixes crewAIInc#7290

Hold _reset_lock across drain_writes() + _storage.delete(), mirroring reset(). _submit_save() registers under the same lock, so a save could otherwise register after the drain snapshot but before the delete, land after it, and resurrect forgotten content. Adds a deterministic test probing the lock from a helper thread (fails pre-fix, passes post-fix).

CodeRabbit follow-up: the lock probe only covered the delete, so a regression draining outside the lock would still pass. Wrap drain_writes with the same helper-thread probe; assert both fail.

bunnysayzz mentioned this pull request Sep 5, 2026

Memory.forget() races pending background saves from remember_many(): forgotten content is resurrected after drain_writes() #7290

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coderabbitai Bot reviewed Sep 5, 2026

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coderabbitai Bot reviewed Sep 6, 2026

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Comment thread lib/crewai/tests/memory/test_memory_forget_drain.py Outdated

bunnysayzz added 3 commits September 7, 2026 21:30

test(memory): probe _reset_lock during drain as well as delete

9c61c59

CodeRabbit follow-up: the lock probe only covered the delete, so a regression draining outside the lock would still pass. Wrap drain_writes with the same helper-thread probe; assert both fail.

bunnysayzz force-pushed the fix/memory-forget-drain-writes-7290 branch from 9607fe3 to 9c61c59 Compare September 7, 2026 16:00

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fix(memory): drain pending saves before forget() deletes records - #7291

fix(memory): drain pending saves before forget() deletes records#7291
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bunnysayzz commented Sep 5, 2026

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bunnysayzz commented Sep 5, 2026

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