docs(devlog): correct the 122-failure root cause to the missing --isolate

[lidge-jun]

Summary

Corrects the root cause recorded in #1783. That note blamed a missing sandbox from scripts/test.ts; that was wrong, and the correction matters because it pointed at the wrong defense.

tests/preload.ts is registered in bunfig.toml exactly so a bare bun test still gets a sandbox and an armed guard. That defense works — a bare bun test <file> on a single file passes.

The actual trigger is the missing --isolate. scripts/test.ts spawns bun test --isolate ./tests/; without it Bun shares one process across all 789 files. The preload runs once per process, so any suite that mutates process.env.OPENCODEX_HOME or restores a captured environment in afterEach can leave a later file pointing at the real home. The guard then correctly refuses, and the refusal surfaces as an unrelated downstream assertion.

Verification

Same host, same commit, same machine:

bun test                     67 refusals, 122 failures
bun test --isolate tests      0 refusals,   0 failures  (12388 pass / 11 skip)
bun run test                  0 refusals,   0 failures  (12388 pass / 11 skip)

The middle row isolates the variable: no wrapper, no sandbox hand-off, only --isolate plus the preload — and it is fully green. It is also the exact command scripts/release.ts runs in preflight, so the release gate is unaffected.

Checklist

• Documentation only; no runtime code changed
• Claim verified by controlled measurement rather than inference
• No credentials or account identifiers recorded

Summary by CodeRabbit

• Documentation
  • Clarified the cause of previously reported test failures.
  • Documented the differences between available test commands and their isolation behavior.
  • Updated operational guidance to recommend the standard test command for reliable results.

[github-actions]

✅ Deterministic PR hygiene checks passed.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 6df428d and 7b7823a.

📒 Files selected for processing (1)

• devlog/_plan/260815_roadmap_closeout/110_release_readiness.md

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📝 Walkthrough

Walkthrough

The release-readiness document now attributes 122 test failures to running Bun without --isolate. It documents preload behavior, OPENCODEX_HOME leakage, measured command results, and recommends bun run test.

Changes

Release readiness documentation

Layer / File(s)	Summary
Bun test isolation guidance devlog/_plan/260815_roadmap_closeout/110_release_readiness.md:20-55	The document replaces the missing-harness explanation with process-sharing behavior. It records cross-file OPENCODEX_HOME leakage, downstream failures, command comparisons, measured results, and recommended test commands.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Possibly related PRs

• lidge-jun/opencodex#1783: Both PRs update the same release-readiness document and explain the 122 raw bun test failures through test isolation behavior.

Suggested reviewers: ingwannu

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch codex/fix-110-rootcause

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