flake: Test process crash - Node IsSafeJsInt assertion during pnpm install

[flake-investigator]

CI Run Link: https://github.com/coder/coder/actions/runs/22620104010
Failed Job: gen (Setup Node)
Commit: c483bfa24f1259ce5dd85081c89a75426fc99b0f (author: Danielle Maywood)
Failure Time: 2026-03-03 11:04 UTC

Error Evidence:

#  node[2422]: void node::fs::WriteBuffer(const v8::FunctionCallbackInfo<v8::Value>&) at ../src/node_file.cc:2218
#  Assertion failed: IsSafeJsInt(args[2])
----- JavaScript stack trace -----
1: writeSync (node:fs:912:22)
2: writeFileSync (node:fs:2445:26)
3: writeFile (/home/runner/setup-pnpm/node_modules/.pnpm/pnpm@10.14.0/node_modules/pnpm/dist/worker.js:4281:21)
...
../scripts/pnpm_install.sh: line 35:  2422 Aborted (core dumped) pnpm install "${pnpm_flags[@]}"
##[error]Process completed with exit code 134.

Root Cause Classification: Process crash (Node runtime assertion) during pnpm install in the gen job. Likely Node 22.19.0 runtime issue or CI runner/filesystem interaction while pnpm writes to the store.

Assignment Analysis:

• git log --oneline -10 --follow scripts/pnpm_install.sh
  • d0037670 chore: only run pnpm when node_modules are out of date in Makefile (#16017) — author: mckayla
• git log --oneline -10 --follow .github/actions/setup-node/action.yaml
  • 4d8dc221 chore: upgrade Node.js from 20.19.4 to 22.19.0 and update dependencies (#19870) — author: Thomas Kosiewski

Assignment: @kylecarbs (CI tooling/infrastructure context; recent setup-node action changes include Node version bumps, but GitHub username for the most recent author was unclear).

Related Issues: None found after searching coder/internal for "IsSafeJsInt", "node::fs::WriteBuffer", "pnpm_install.sh", "exit code 134".

Reproduction: Not known; occurs in CI during pnpm install on self-hosted runner.