Observed CI failure
Stacks CI run 34858502193, job artifact-freshness, uses the action pinned at fa35547da630b14beda5b26a2625490864d5c963 with install: 'false'.
The action tries to install Bun 1.4.2. GitHub's release download returns HTTP 504 on all four attempts. Setup Pantry emits a warning and succeeds. The next step, bun install --frozen-lockfile, fails with bun: command not found (exit 127).
Verified source path
packages/action/src/index.ts, lines 832-849 explicitly describes providing Bun as the setup-only contract. However, the surrounding catch handles a failed installSystemPackage('bun.sh', ...) only with core.warning, and execution continues.
Expected
If the required runtime cannot be installed, fail the setup action at that boundary and retain the download error. Do not report successful setup and defer the failure to an unrelated downstream command. Test the rejected-install path for install: false, alongside its successful runtime setup path.
This request is not to increase retry counts, add a Stacks-specific setup workaround, or suppress the downstream command's failure. The download already retried four times. The defect is the action's success status after its required setup failed.
The same Stacks run passed its test, typecheck, lint, compile, scaffold-smoke and deployment-target jobs; this artifact-freshness failure is separate from those code checks.