Section: ci
Rank: T2 · Sensitive: yes (deploy, promotion) · Builder: Opus high · Size: under 50 product lines, one PR · Depends on: the .nvmrc pin PR (lane OA-Fix-Node2422).

What is wrong

Under Node 24.22.0 every promotion is refused before anything is migrated or promoted:

{"kind":"refused","reason":"ops-astro-0123456789ab could not be copied: ERR_FS_CP_EEXIST; nothing was migrated or promoted"}

frozenCopy makes the copy's folder with mkdtempSync and then copies the artefact into that same, now existing, folder with errorOnExist: true, force: false (scripts/ops/served-copy.ts:73-75). Node 24.22.0 shipped nodejs/node#64124 ("fs: throw on existing dir in cpSync with errorOnExist", commit f3019b522a): onDir in lib/internal/fs/cp/cp-sync.js:136-145 now throws ERR_FS_CP_EEXIST when the destination folder exists, where 24.21.0 merged into it. The catch at served-copy.ts:80-84 turns that into the refusal above.

Red on 24.22.0, green on 24.21.0 (lane OA-Fix-Node2422, Mac arm64, checksummed nodejs.org binaries, main 49c7759): tests/ci/promotion-frozen-copy.test.ts (10), tests/ci/promotion-trust-chain.test.ts (2), tests/review/main-b1-p12-promotion-relative-link-proof.test.ts (1); 12 failed / 30 on 24.22.0, 30/30 on 24.21.0. CI moved to 24.22.0 on 18 Oct because .nvmrc said 24 (job 118178985475, runner image 20261018.339.1). The pin PR holds .nvmrc at 24.21.0 until this lands.

It is not only CI: node scripts/ops/promote.mjs runs on whatever Node the operator's host has, so a host on 24.22.0 or later refuses every promotion (fail-closed: nothing migrated, production's link unchanged).

What to build

• frozenCopy copies into a name that does not exist yet inside its private temporary folder (for example join(copy, 'bytes')), keeping errorOnExist: true, force: false so an entry already there is still refused, and the rename, digest check and served modes act on that path. Or another shape that keeps the same guarantees; never drop errorOnExist.
• Check servedModes still sets every mode under 24.22.0's other cpSync change, fs: copy directory trees for fs.cp() on the thread pool nodejs/node#65488 ("give directories created by cpSync the source directory's mode"): the umask-077 and closed-to-others cases in promotion-frozen-copy.test.ts cover it.
• Put .nvmrc back to 24 in the same PR, so CI follows the Node 24 line again.

Done when

• The three files above are green on 24.22.0 and 24.21.0, with no test edited to get there.
• .nvmrc reads 24 and the merge group's shard 3 is green on the current Node 24.

Not in scope

scripts/ops/release.ts:64 and scripts/ops/web-deploy.ts:162 call cpSync without errorOnExist, so #64124 does not touch them.