Runway DLQ answers FAILED for a merge whose push already landed

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难度
4/5
预计耗时
3-5 天
新手友好度
55/100
Issue 类型
缺陷
描述清晰度
描述清楚
活跃度
活跃
技术栈
go
领域
distributed-systems

调研方向

Start with runway/controller/dlq/dlq.go and the merger’s existing branch-containment check used for idempotence; the issue does not name that code’s file. Add a unit test for a successful push followed by failed answer publishing until dead-lettering. Done means the DLQ answers MERGED when the request’s changes are already on the target branch and never reports that landed request as FAILED.

由索引模型根据 Issue 内容生成。

描述

bug

Problem

Runway can tell SubmitQueue that a merge failed after the merge has landed on the target branch. landsignal applies the FAILED, and the batch and its requests are reported failed for a change that is on main.

Cause

Runway's merge DLQ (runway/controller/dlq/dlq.go) answers FAILED unconditionally; Runway is stateless and never checks whether the push happened. The merge controller pushes first and publishes its answer afterwards:

runway merge:  push lands on the target branch
runway merge:  publishing SUCCEEDED keeps failing; retries re-run the merge (idempotent: no new commits)
               → retries exhaust → runway-merge DLQ
runway DLQ:    publish FAILED under a distinct message ID, so it is not deduped
landsignal:    batch landing → failed

The git merger's redelivery idempotence covers the merge controller's retries. Nothing covers the DLQ's answer. No orchestrator-side fix (#819) can repair this.

Direction

Check the branch before answering: answer MERGED when the request's changes are already contained in the target ref, FAILED otherwise. The merger already computes this for idempotence. Note the residual hazard recorded in #819: once the DLQ has honestly answered FAILED, a later re-send of the same request must not merge.

Found by model checking spec/submitqueue/landoutcome/LandOutcome.tla.

Acceptance criteria

  • Runway's DLQ never answers FAILED for a request whose changes are on the target branch.
  • Unit test: the push succeeds, the answer publish fails until dead-lettered, and the DLQ answers MERGED.
主要语言
Go
星标
247
派生
16
平均合并
2 天 1 小时
30 天内合并 PR
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环境准备

从这里开始

  1. 先读完整个 Issue，再读项目的贡献指南。
  2. 在 Issue 下留言说明你要接手 —— 这能避免两个人做同样的事。
  3. Fork 仓库，在一个分支上完成修改。
  4. 提交 Pull Request，并在描述里引用这个 Issue 编号。

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