Summary

Adds an opt-in snapshot: false runner option that skips the workspace backup after a successful command.

Motivation

Every successful runner ends with createBackup() of /workspace so that a chained runner can restore it. The last runner of a pipeline, typically a deploy step, has nothing chained after it, so its backup is never restored. Producing it still adds a few seconds to the step (for example backup.create … (2833ms) after a deploy command in our pipeline), and the archive stays in R2 until its TTL expires.

Usage

const built = await ci.runner({ name: 'build', command: 'bun run build' });

await built.runner({
  name: 'deploy',
  command: 'bun run deploy',
  snapshot: false,
});

Behavior

• The Sandbox runner does not call createBackup for that step, and the step succeeds without a snapshot.
• Calling .runner() on such a result rejects with an error, since there is no workspace to restore.
• snapshot: false combined with cache is rejected before the step runs, because the cache pointer needs the snapshot.
• Runners that don't set the option behave exactly as before. The only type change is that CiRunStepOutput.snapshot (and so CiRunnerResult.snapshot) becomes optional.

Tests

Focused tests cover each layer:

• the Sandbox runner skips the backup;
• runCiStep forwards the option and returns no snapshot;
• withStepNotification accepts a missing snapshot only when none is required;
• CIWorkflow rejects chaining from an opted-out runner and rejects the combination with cache.

Results:

• vitest run --dir src: 89 passed; the 5 new tests fail without the change.
• typecheck, lint and format:check pass, with no new lint warnings.

Naming

I named the option snapshot: false to sit next to cache, and I'm happy to rename or reshape it if you'd prefer another API.