fix(release): keep generated release notes when the write-back fails

[shashank-100]

Problem

scripts/changeset-version.ts keeps Hunk's changelog canonical at the repository root by staging it beside packages/hunk, running Changesets, and copying the generated result back. The cleanup ran in a finally:

copyFileSync(packageChangelog, canonicalChangelog);   // write-back
} finally {
  rmSync(packageChangelog, { force: true });          // always deletes
}

If the write-back fails — disk full, permissions, an interrupted write — the staged file is deleted anyway. At that moment it holds the only copy of the new release notes: Changesets has already consumed the .changeset/*.md entries that produced them, and the root still contains pre-version content. The generated history is gone and recovery is manual, during a release.

Approach

Remove the staged copy only once it is reproducible again. A failure before Changesets produced output still cleans up and rethrows unchanged; a failure after leaves the generated file in place and reports where to find it:

Failed to return the generated changelog to <root>/CHANGELOG.md.
The generated history is preserved at <package>/CHANGELOG.md;
move it to the repository root before retrying.

Non-goals: the staging strategy, the canonical-root invariant, and the success path are unchanged. This only narrows when the cleanup is allowed to run. The original error is attached as cause.

Why core

Release tooling under scripts/, alongside the code it fixes. No runtime or extension surface is involved.

Tests

Added keeps the generated changelog when it cannot be returned to the root in scripts/changeset-version.test.ts. It makes the write-back fail after Changesets has produced output, then asserts the generated notes survive. Confirmed to fail on the unfixed code (raw EACCES, staged file already deleted) and pass with the fix.

The existing removes the staged package changelog when Changesets fails test still passes, so the pre-output failure path is unchanged.

Beyond the test, I verified the data loss directly against both versions of the function:

===== WITH FIX =====
threw: Failed to return the generated changelog to /var/folders/.../CHANGELOG.md
staged file still exists?  true
generated notes recoverable? YES

===== WITHOUT FIX (original code) =====
threw: EACCES: permission denied, copyfile '.../packages/hunk/CHANGELOG.md' -> '.../CHANGELOG.md'
staged file still exists?  false
generated notes recoverable? NO — DATA LOST

Commands run

bun run typecheck    # clean
bun run lint         # 0 warnings, 0 errors
bun test scripts/changeset-version.test.ts   # 4 pass, 0 fail
bun run test         # 3846 pass, 47 skip, 2 fail

The 2 full-suite failures are not from this change; the diff touches only scripts/changeset-version.*:

• install VM contract > allows cleaning only real harness-owned paths... — pre-existing on main. Reproduced on a clean tree at upstream/main: bun test test/cli/install-vm/contract.test.ts → 10 pass, 1 fail. The harness compares a realpathSync-resolved root against an unresolved target, so macOS's /var → /private/var symlink breaks the containment check.
• filesystem watch observer and Jujutsu source reading failures appear only under full-suite parallel load and are timing-sensitive. Re-running bun test packages/hunk/src/core/watch/ with this change applied gives 68 pass, 0 fail.

Platforms

Verified on macOS (darwin 25.6.0). The new test skips on Windows and as root, where the permission denial it depends on does not hold; the fix itself is platform-neutral node:fs control flow.

Changeset

Empty, per CONTRIBUTING — this is release tooling with no user-visible behavior change.

Follow-up

Found while reviewing e76b0039; noted as a follow-up in #1007 and split out here so each change is reviewable on its own. Independent of #1007 — branched from main, no shared files, either can merge first.

🤖 Generated with Claude Code

https://claude.ai/code/session_019jAgP7j1gaT9fSk5syLHDH

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