[lidge-jun]

Summary

Fixes a startup race in the ocx.quota-pool/1 identity (#7476), which showed up in CI as a flaky servers racing on a fresh home agree on one identity (PR #7488, test 2/4: three children printed home_cb8f…, one printed "").

Root cause. A losing process read no identity file. The winner then linked its complete file in. The loser's own existence check found that file and threw quota-pool identity file is not a valid regular file. The child that printed "" was that loser: it crashed, and its error went to stderr. No empty or partial identity was ever published or memoized, because the hard-linked file is complete the moment it appears. The impact was a spurious startup error, and /api/quota-pool answered quota_pool_identity_unavailable on that server until a later read found the file.

Reproduced locally before the fix: 2 of 40 rounds of 8 concurrent processes, every failure with that message. After the fix: 0 of 40.

Fix (src/quota-pool/identity.ts):

• A loser that finds a file at the path re-reads it within a bound (50 × 10 ms) and adopts it once it is valid. This covers a file that appears between its two checks, and the brief empty window of the no-hard-link fallback, which creates the file before writing it. An empty or invalid identity is never returned or memoized.
• A symlink, or a file that stays malformed past the bound, is still refused and left untouched.
• The temp file and the in-place fallback are fsynced before publication. The parent directory is fsynced after publication (best effort, skipped on Windows), so a power loss cannot drop the entry and rotate the identity.
• Test-only hooks expose both windows so they can be forced without sleeping.

Verification

• New deterministic regressions in tests/usage/quota-pool.test.ts:
  • A winner published inside the window between the absence read and the existence check is adopted, not refused. With the old throw line restored, this fails with exactly the CI error.
  • Losing the hard-link race (EEXIST) adopts the winner's complete file, and the loser's temp file is cleaned up.
  • An in-place create observed before its bytes are written: a reader gets null, a concurrent loser throws instead of returning or memoizing the empty file, and a fresh read then returns the writer's complete identity.
• The race harness now reads each child's stdout, stderr and exit code, and asserts { id: persisted, code: 0, error: "" } for every child. The assertion is stricter than before, and a failing child now names its error.
• Race test 50× under /usr/bin/lockf -t 3600 /tmp/ocx-heavy-test.lock: 50 pass / 0 fail, run twice (before and after the directory-fsync change).
• bun run typecheck, bun run test:changed (8328 pass / 31 skip / 0 fail), tests/server/quota-pool-relay.test.ts and tests/server/link-management-relay.test.ts, bun run structure:check and bun run privacy:scan: all pass.
• The full bun run test was not rerun for this two-file change; CI covers the rest.

Checklist

• Scope stays focused and avoids unrelated cleanup.
• Docs or release notes were updated when needed.
• Security-sensitive changes were reviewed for secrets, auth, and unsafe defaults.

Summary by CodeRabbit

• Bug Fixes
  • Improved quota-pool identity creation during concurrent access, ensuring processes consistently adopt the published identity.
  • Added safeguards against reading incomplete, malformed, symlinked, or otherwise invalid identity files.
  • Improved recovery when identity files are created or linked simultaneously.
  • Prevented incomplete identities from being returned or cached.
  • Improved cleanup of temporary files left by competing identity creation attempts.

[github-actions]

✅ Deterministic PR hygiene checks passed.

[chatgpt-codex-connector]

Codex Review Summary

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-21T15:29:08.977631Z	96f8296	PR opened

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📒 Files selected for processing: 2

• src/quota-pool/identity.ts
• tests/usage/quota-pool.test.ts

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📝 Walkthrough

Identity creation now flushes new files and their parent directory before publication completes. Concurrent readers use bounded retries to adopt valid identity files. Tests cover incomplete files, race paths, cleanup, and multi-process results. Documentation describes the retry and validation behavior.

Changes: Quota-pool identity publication

Layer / File(s)	Summary
Durable publication and retry primitives src/quota-pool/identity.ts:17-138	Identity creation flushes file contents and synchronizes the parent directory. Test hooks and bounded reads validate concurrently published files and reject invalid file types or malformed content.
Concurrent publication paths src/quota-pool/identity.ts:143-188	Identity acquisition, hard-link EEXIST, and exclusive-create conflicts use bounded retries to adopt a concurrently published identity.
Race tests and documented behavior tests/usage/quota-pool.test.ts:7-254, structure/quota-pool.md:68-73	Tests cover complete and incomplete publication, loser temporary-file cleanup, hook reset, and each racing process’s output, error stream, and exit status. Documentation describes the retry window and validation behavior.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Bug fix

Merge Risk: ⚪ Minimal · up to 02a29

The identity race paths appear ready to merge after normal checks; no outstanding issue was established.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 62.50% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 8 functions across 2 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the primary change: losing processes adopt a concurrent winner’s identity instead of rejecting it.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

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Actionable comments posted: 2

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• 🪄 Fix comments: Fix CodeRabbit comments on this PR

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Inline comments:
Review comments at @src/quota-pool/identity.ts:
- Line 156: After each successful identity publication in the flow using
linkSync and createExclusive, perform a best-effort fsync of the parent
directory, skipping this step on Windows; add a focused fsyncDirectory helper
using dirname, openSync, fsyncSync, and closeSync, while preserving publication
success even if directory syncing fails.

Review comments at @tests/usage/quota-pool.test.ts:
- Around line 186-220: Add a deterministic test alongside the existing
quota-pool identity race tests that configures the
setQuotaPoolIdentityHooksForTests link hook to write a complete winner identity
to the target, then throw an EEXIST error. Assert that ensureQuotaPoolIdentity()
adopts and returns that winner identity.

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• src/quota-pool/identity.ts
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[lidge-jun]

Merged with owner authority per maintainer decision 2026-10-21 (jun): the project owner authorized owner-path (--admin) merges for the pending green PRs after the 2.90.0 release; no second-maintainer approval is available.

Exact-head verification on 32c4068bc3b5a31fb342d9ed976100cb7f56ca2e: all checks completed with no failures, the PR is mergeable, there are no change requests, and no unresolved current Major/Critical/P0/P1 review threads. A local squash of this head onto current dev 79fa35066 passed typecheck, structure:check, the file-size, import-cycle and test-layout ratchets, and this PR's own tests ( 115 pass 0 fail ). Windows-sensitive: true (Cross-platform CI lane=all on this head: https://github.com/lidge-jun/opencodex/actions/runs/39663848794); PR CI never runs Windows (AGENTS.md CI policy), so a Windows-sensitive PR merges only after a green lane=all dispatch. The merge is a squash pinned with --match-head-commit.