Fix pnpm installs of read-only package files

[aghiles-dd]

Problem

With Yarn 6.0.0-rc.22 and nodeLinker: pnpm, installing a tarball containing a file with mode 0555 fails with Permission denied in fs_extract_archive_impl. link_into_cas applies the read-only mode before set_safe_mtime reopens the entry for writing. The failed install leaves a read-only cache entry that subsequent installs cannot rewrite.

Changes

Set the timestamp before restoring archive permissions. When repairing an existing cache entry, temporarily allow owner writes and repair it in place, preserving its inode and existing cross-project hardlinks.

Add one regression case to the existing content-addressed index suite covering installation and repair of a read-only file, including its final permissions.

Validation

• The new regression fails on the released 6.0.0-rc.22 binary with the original permission error.
• All six content-addressed index integration tests pass with the patched release build, including cross-project hardlink repair.
• ESLint and git diff --check pass.
• A full pnpm install and subsequent install --immutable pass in the affected monorepo with the patched binary.

A fresh install of the affected monorepo with released Yarn 6.0.0-rc.22 and nodeLinker: pnpm fails with Permission denied. Reproduced using a new YARN_GLOBAL_FOLDER with an empty cache and content-addressed index.

[netlify]

👷 Deploy request for yarn-v6 pending review.

Visit the deploys page to approve it

Name	Link
🔨 Latest commit	f08346a

[github-actions]

⏱️ Benchmark Results

gatsby install-full-cold

Metric	Base	Head	Difference
Mean	4.384s	4.337s	-1.06% ✅
Median	4.373s	4.337s	-0.83% ✅
Min	4.279s	4.259s
Max	4.470s	4.440s
Std Dev	0.052s	0.044s

📊 Raw benchmark data (gatsby install-full-cold)

Base times: 4.279s, 4.304s, 4.399s, 4.352s, 4.341s, 4.441s, 4.447s, 4.368s, 4.413s, 4.346s, 4.385s, 4.423s, 4.440s, 4.436s, 4.341s, 4.350s, 4.350s, 4.460s, 4.357s, 4.422s, 4.333s, 4.342s, 4.369s, 4.439s, 4.378s, 4.329s, 4.456s, 4.330s, 4.470s, 4.424s

Head times: 4.367s, 4.298s, 4.319s, 4.375s, 4.291s, 4.330s, 4.397s, 4.281s, 4.266s, 4.348s, 4.375s, 4.440s, 4.351s, 4.343s, 4.348s, 4.331s, 4.316s, 4.314s, 4.368s, 4.308s, 4.279s, 4.311s, 4.259s, 4.305s, 4.374s, 4.301s, 4.408s, 4.349s, 4.389s, 4.382s

---

gatsby install-cache-only

Metric	Base	Head	Difference
Mean	1.306s	1.343s	+2.82% ⚠️
Median	1.303s	1.317s	+1.03% ⚠️
Min	1.289s	1.289s
Max	1.326s	2.146s
Std Dev	0.009s	0.152s

📊 Raw benchmark data (gatsby install-cache-only)

Base times: 1.321s, 1.319s, 1.311s, 1.291s, 1.294s, 1.314s, 1.311s, 1.314s, 1.303s, 1.311s, 1.300s, 1.301s, 1.323s, 1.326s, 1.301s, 1.313s, 1.304s, 1.301s, 1.298s, 1.289s, 1.301s, 1.302s, 1.305s, 1.306s, 1.302s, 1.295s, 1.304s, 1.302s, 1.299s, 1.311s

Head times: 1.296s, 1.305s, 1.289s, 1.296s, 1.300s, 1.323s, 1.315s, 1.308s, 1.324s, 1.319s, 1.316s, 1.322s, 1.317s, 1.316s, 1.314s, 2.146s, 1.329s, 1.330s, 1.317s, 1.340s, 1.317s, 1.309s, 1.320s, 1.320s, 1.298s, 1.308s, 1.316s, 1.310s, 1.332s, 1.323s

---

gatsby install-cache-and-lock (warm, with lockfile)

Metric	Base	Head	Difference
Mean	0.374s	0.373s	-0.18% ✅
Median	0.372s	0.371s	-0.25% ✅
Min	0.363s	0.363s
Max	0.419s	0.383s
Std Dev	0.010s	0.005s

📊 Raw benchmark data (gatsby install-cache-and-lock (warm, with lockfile))

Base times: 0.366s, 0.378s, 0.367s, 0.371s, 0.376s, 0.372s, 0.370s, 0.371s, 0.374s, 0.384s, 0.373s, 0.371s, 0.378s, 0.380s, 0.381s, 0.369s, 0.368s, 0.374s, 0.382s, 0.378s, 0.373s, 0.373s, 0.419s, 0.367s, 0.366s, 0.366s, 0.363s, 0.367s, 0.372s, 0.374s

Head times: 0.365s, 0.367s, 0.373s, 0.370s, 0.371s, 0.370s, 0.380s, 0.370s, 0.370s, 0.363s, 0.371s, 0.366s, 0.374s, 0.382s, 0.370s, 0.371s, 0.373s, 0.369s, 0.381s, 0.381s, 0.380s, 0.376s, 0.378s, 0.379s, 0.379s, 0.369s, 0.372s, 0.378s, 0.371s, 0.383s

[arcanis]

rather than checking for existence we should rather tolerate enoent errors (see ok_missing)