Optimistic mutation does not roll back on failure

同一個缺陷，每一個視角

• 使用者

  The item is on the list. Reload and it is gone. Nothing said the save failed.

• 執行期

  The mutation promise rejects. The rejection is caught and logged, and the local store is never touched again.

• 架構

  Local state was written before the remote write was known to succeed, and no compensating action exists for the failure branch.

• AI 生成

  The generated handler covers the success path in full and the failure path only as a log line — the shape you get when the prompt describes what should happen and not what happens when it does not.

判斷軌跡

1. 條件 · 依賴any-async-transport2026-08-01 12:30 → 至今信心 0.71
2. 何事 · 使用者stale-ui2026-08-01 12:02 → 至今信心 0.99
3. 何處 · 架構transaction-boundary2026-08-01 12:24 → 至今信心 0.84
4. 為何 · 執行期race-condition2026-08-01 12:05 → 2026-08-01 12:22信心 0.42已被取代
5. 為何 · AI 生成omitted-failure-path2026-08-01 12:22 → 至今信心 0.92

觀察記錄

1. 2026-08-01 12:00已捕捉

   HTTP 500 reproduced with the optimistic item still on screen.

2. 2026-08-01 12:05調查中

   First reading: a race between two writes.

3. 2026-08-01 12:20已重現

   Single-write reproduction refutes the race.

4. 2026-08-01 12:22已定位

   The failure branch never restores state. Classification revised.

5. 2026-08-01 12:28已修補

   First patch rejected; second attaches a rollback.

6. 2026-08-01 12:33待驗證

   Regression test attached.

7. 2026-08-01 12:35已驗證

   pre failed, post passed.

可執行見證

假設

• refuted

  Two concurrent writes interleave and the later one wins.

  Reproduced with a single write. The failure needs no concurrency at all.

• supported

  The error handler never restores the pre-mutation state.

證據

• reproduction · 2026-08-01 12:02

  Forced POST /todos to return HTTP 500. The optimistic row stayed visible; a reload removed it.

• execution · 2026-08-01 12:20

  Single sequential write, no concurrency. Same outcome — refutes the race hypothesis.

• test_result · 2026-08-01 12:33

  Regression test fails against pre and passes against post.

修補

• rejected

  Disable the optimistic update entirely.

  Rejected: removes the behaviour instead of completing it, and the latency it hid is real.

• accepted

  Restore the captured previous state inside the async error handler.

關聯

• manifested_asBE-0001
• same_root_asBU-0003