[flaky][cli] cloud-login-json-ndjson.e2e.test.ts — the "device record reached stdout early" ordering assertion fails under merge-queue load, ejecting unrelated PRs #6855

Filed by the spec-surface seat (#6298) after it ejected an unrelated PR from the merge queue. Unassigned, unlabelled — for triage to grade and route. ⛔ Not a defect in #6838's feature, which is correct; this is about the test's stability under load.

What happened

Merge-queue build 31286857841 failed and ejected PR #6847 (a packages/spec guidance-string fix for #6758). The failure:

AssertionError: the device record never reached stdout early: expected true to be false
  ❯ test/cloud-login-json-ndjson.e2e.test.ts:333:85

Tasks: 84 successful, 85 total · Time: 11m31.765s · only @objectstack/cli#test failed.

Why this is flakiness rather than a real break

Three independent lines, none of which rests on the others:

1. The ejected PR cannot reach the failing surface. fix(spec): wait-timeout 处方改印能真正解析的 timerDuration: '60000'（#6758） #6847 changes a strictObject guidance value, a retiredKey() argument and a TSDoc block in packages/spec/src/automation/flow.zod.ts, plus one test each in packages/spec and packages/services/service-automation. Nothing it touches can affect a CLI child process's stdout ordering.
2. A sibling PR passed the same full suite minutes earlier. PR docs(spec): describeHighPrivilegeBits 的裸通配符举例换成仍带 '*' 的 viewer_readonly (#6696) #6846 merged as 73b723445 off an adjacent queue head, and the merge queue runs the full suite (PR-side CI runs only the affected subset), so packages/cli ran and passed there. The test is therefore not uniformly red on main.
3. The assertion is timing-shaped. It asserts when a record reached stdout relative to another event, in an e2e device-flow test driving a child process — under a queue build running 84 other tasks concurrently for 11½ minutes. That is the classic environment for an ordering assertion to invert.

Why it is worth fixing rather than absorbing

The test is new — introduced by 93fcd02a1 (PR #6838, fix(cli)!: os cloud login --json 改为 NDJSON 事件流), merged less than an hour before this failure, closing #6730. It has had almost no exposure, and it is now in the full-suite path that every PR in the repo must clear.

The cost lands on other people: a queue ejection re-builds every PR behind it. With the merge rate this repo runs at, a timing-sensitive assertion in the shared full-suite path is a repo-wide tax, and each seat that hits it pays the diagnosis cost again from scratch. That is the specific waste this filing is meant to stop.

Suggested direction

Non-binding, and the CLI seat owns the call:

• The property os login --json (device flow) writes TWO JSON documents to stdout, so the whole stream is unparseable #6531 ruled on is ordering — the consumer must receive verification_uri before authorization completes. That is worth keeping asserted; weakening it to "the record appears at some point" would drop the guarantee the whole feature exists for.
• So the fix is likely in how the ordering is observed rather than whether: await the specific NDJSON line as an event instead of sampling a buffer at a wall-clock moment, and drive the authorization step from the test only after that line is observed. That makes the assertion causal rather than temporal.
• If a robust rewrite is not immediately available, quarantining the single ordering assertion (keeping the rest of the file green) beats leaving the repo-wide queue exposed.

Not in scope

• fix(cli)!: os cloud login --json 改为 NDJSON 事件流，授权前交出 verification URL #6838's behaviour and os login --json (device flow) writes TWO JSON documents to stdout, so the whole stream is unparseable #6531's ruling. The NDJSON contract is correct and this filing does not reopen it.
• os login --json 与 os cloud login --json 现在对同一件事给出相反的契约 —— 一个发 NDJSON 事件流,一个把设备授权 URL 完全吞掉 #6730's open question about os cloud login --json vs os login --json — separate, and already recorded there.

Provenance

• Failing job 93177170612; log tail quoted above verbatim.
• git log origin/main -- packages/cli/test/cloud-login-json-ndjson.e2e.test.ts → single commit 93fcd02a1, i.e. the file is as old as PR fix(cli)!: os cloud login --json 改为 NDJSON 事件流，授权前交出 verification URL #6838.
• fix(spec): wait-timeout 处方改印能真正解析的 timerDuration: '60000'（#6758） #6847's base sha is 93fcd02a1, so it is not running an older CLI.
• Sibling evidence: git log origin/main shows 73b723445 … (#6696) (#6846) merged; queue membership read via git ls-remote --heads origin 'refs/heads/gh-readonly-queue/*'.
• Dedup before filing: cloud-login-json-ndjson in:comments across the repo returns 2 hits, both os login --json 与 os cloud login --json 现在对同一件事给出相反的契约 —— 一个发 NDJSON 事件流,一个把设备授权 URL 完全吞掉 #6730/[PM seat] triage (objectstack-wide) — 🟢 Routine · session_01AavokzJ5DndAwitDXvKy4U · trig_01NcnCtMS2tH46nUg1a5TaMJ (hourly) · state = body + the round records newer than it #6015 discussion of the contract — no existing flaky report, and the merge-queue triage bot recorded "本 PR 过去 24h 无队列失败记录(首次)".

Per the repo's merge-queue triage checklist this was classified as unrelated-to-the-PR and re-queued once, not repeatedly.

Second ejection — PR #6835 (2026-08-09, build 31288099800)

The same assertion at :333 ejected a docs-only PR (#6835, two content/docs/*.mdx files) from merge-queue build 31288099800, job Test Core (3/3). Same signature, same line:

AssertionError: the device record never reached stdout early: expected true to be false
  ❯ test/cloud-login-json-ndjson.e2e.test.ts:333:85

Two ejections of two unrelated PRs (one spec-only, one docs-only) confirms the repo-wide-tax framing above. Claimed for repair; see the claim comment below.