Set last hook exit status for unwrapped hooks

[francoiscampbell]

Description

Unwrapped hooks (non-shell scripts and binaries) currently do not update BUILDKITE_LAST_HOOK_EXIT_STATUS. This differs from wrapped shell hooks and can leave the variable unset or stale for subsequent hooks, even when the unwrapped hook succeeded.

Set the variable from the unwrapped process result so later hooks observe the same exit-status behavior regardless of hook type.

Context

This surfaced after converting a plugin command hook from Bash to Python. Its pre-exit hook used BUILDKITE_LAST_HOOK_EXIT_STATUS to report the command result, but the value was no longer populated after the successful Python hook.

Changes

• Set BUILDKITE_LAST_HOOK_EXIT_STATUS after running an unwrapped hook, using the same shell.ExitCode conversion as wrapped hooks.
• Add regression coverage for successful and failing unwrapped hooks.

Testing

• Tests have run locally (with go test ./...). Buildkite employees may check this if the pipeline has run automatically.
• Code is formatted (with go tool gofumpt -extra -w .)

Passed:

go test ./internal/job -run '^TestRunUnwrappedHookSetsLastHookExitStatus$' -count=1

Affiliation (optional, external contributors)

Instacart

Disclosures / Credits

OpenAI Codex via Pi helped diagnose the behaviour, implement the change, and write the regression test. The PR was then reviewed and refined by a human.

[francoiscampbell]

Could a maintainer please add the bug label? This fixes BUILDKITE_LAST_HOOK_EXIT_STATUS not being updated for unwrapped hooks. External contributors do not have permission to add labels in this repository.