verify-action-build: support Dart-based actions (setup-dart)#741
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Actions such as dart-lang/setup-dart compile their source from Dart to JavaScript in the `build` npm script (`dart compile js ...`) and then bundle via a bare `ncc build` invocation in `dist`. The node:slim base image has neither the Dart SDK nor `@vercel/ncc`, so the build loop silently fell through to the `npx ncc build --source-map` fallback, producing an incomplete rebuild missing `main.cjs` and `sig.txt`. When a `pubspec.yaml` is detected at the repo root, install the Dart SDK from Google's apt repo, install `@vercel/ncc` globally, and run `dart pub get` so the pubspec dependencies resolve before compilation. Also add `all` to the list of candidate npm scripts so actions whose `all` script chains build+package steps (the setup-dart convention) run as a single step. With these changes, `verify-action-build --from-pr 739` against dart-lang/setup-dart@e51d8e571e22 reports "All compiled JavaScript matches the rebuild". Generated-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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dave2wave
approved these changes
Apr 19, 2026
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Summary
Teach
verify-action-buildto rebuild actions whose source is written in Dart (e.g.dart-lang/setup-dart).When a
pubspec.yamlexists at the repo root, the Dockerfile now:@vercel/nccglobally (setup-dart'sdistscript invokes barencc buildrather thannpx ncc, so it has to be onPATH).dart pub getso pubspec dependencies (path,pub_semver, …) are resolved beforedart compile js.Also adds
allto the list of candidate npm scripts — setup-dart'sallscript chainsbuild+distas one step, and other actions use the same convention.Why this was broken
Without these tools the Dockerfile's
npm run build/package/startloop failed silently (2>/dev/null) and fell through to thenpx ncc build --source-mapfallback. That produceddist/index.mjsbut omitteddist/main.cjs(the dart2js output) anddist/sig.txt(generated bydart tool/sig.dart), so every rebuild of a Dart action diffed against the published one.Verification
Against PR #739 (allowing
dart-lang/setup-dart@e51d8e571e22):Before:
After:
Test plan
uv run utils/verify-action-build.py --from-pr 739 --cipasses againstdart-lang/setup-dart@e51d8e571e22