サンプル

Configuring abandon_on_cancel=False on anyio.to_thread.run_sync shields worker execution and blocks scope cancellation until the worker thread finishes, while abandon_on_cancel=True exits immediately but releases the CapacityLimiter slot before the background worker thread completes.

sha256:a14bcf1e15305a5701519193880ecabc0aab24fe04d053c597a482f66f869313

ケース

ゴール

Configuring abandon_on_cancel=False on anyio.to_thread.run_sync shields worker execution and blocks scope cancellation until the worker thread finishes, while abandon_on_cancel=True exits immediately but releases the CapacityLimiter slot before the background worker thread completes. HOW

パッケージ

anyio 4.13.0

環境

python

作成日

2026-08-17T11:44:01Z

よくある思い込み

Cancelling a task waiting on anyio.to_thread.run_sync cancels immediately without waiting for the synchronous thread, and setting abandon_on_cancel=True keeps worker thread concurrency strictly bounded by the CapacityLimiter.

このサンプルの作者が、ここで開発者やモデルが期待するであろうこととして記録したもの。下の契約が実際に実行されたものだ。

コントラクト

• With abandon_on_cancel=False, cancelling the calling scope blocks until the worker thread finishes running, whereas abandon_on_cancel=True exits the scope immediately while releasing the CapacityLimiter before the synchronous thread finishes.
• assert cancel_scope.cancel_called and sync_finished, 'With abandon_on_cancel=False, cancellation must be shielded until worker thread finishes'
• assert elapsed >= 0.18, 'Scope exit was blocked waiting for synchronous thread duration'
• assert elapsed < 0.15 and not sync_finished, 'With abandon_on_cancel=True, scope exits immediately while worker thread runs in background'
• assert limiter.available_tokens == 1 and limiter.borrowed_tokens == 0, 'CapacityLimiter token is immediately released upon cancellation despite worker thread running'
• assert acquired_concurrently, 'Second task acquires limiter token concurrently with abandoned background thread'
• assert collision_caught, 'Calling run_sync while holding default limiter raises RuntimeError'

ファイル

• NOTES.md
• csx.json
• requirements.txt
• test/contract.py

ソースアーティファクトをダウンロード (tar.gz)

オリジンシーダー

csx-seed

検証レシート

• python 3.12 · linux alpine/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · python@1 · 2026-08-17 · ed25519:d91480838ac982c9