ci(dart): analyze, format and test the packages under dart/

[diegolopezrm]

Description

Fixes #2493, and answers the lint half of #2463.

dart/a2ui_core and dart/a2ui_agent — the two packages this repository publishes to pub.dev — are not covered by any CI job. The Flutter workflow's matrix comes from find samples -name pubspec.yaml, so dart/ never enters it; no other workflow runs dart analyze or dart test; and fix_format.sh formats samples/client/flutter renderers/flutter, which does not include dart/ either. #2374 changed MessageProcessor and was merged without CI ever running that package's tests.

This adds dart_packages_test.yml, modelled on flutter_packages_test.yml, holding those packages to the same bar as the samples: dart pub get, dart format --output=none --set-exit-if-changed, dart analyze --fatal-infos, dart test. The matrix is generated the same way the Flutter one is, so a new package under dart/ is picked up with no workflow edit.

Both packages pass all four steps today: a2ui_core 74 tests, a2ui_agent 1, and the analyzer is clean in both after the first commit here.

Why --fatal-infos, and why it answers #2463

The analyzer reports lint violations as infos. A Dart job without --fatal-infos exits 0 on a file that breaks every rule in analysis_options.yaml, so the flag is what makes this a lint gate rather than a compile check. The samples already use it (flutter analyze --fatal-infos).

For the question in #2463 — "are we applying the lints that we expect?" — this is the part that was actually missing. The warnings in that issue come from dart format, which reads analysis_options.yaml only for its formatter: section (page_width) and never for lint rules; this repository sets no formatter: section, so the unresolved include leaves formatting output unchanged. What does change that output is the language version, which fix_format.sh already pins for exactly that reason. Neither path applies a single lint to dart/, because no job analyzes it.

Why Flutter and not a Dart-only SDK

The packages use resolution: workspace, and the root pubspec.yaml declares flutter: ">=3.35.7 <4.0.0" and lists the Flutter samples in its workspace, so dart pub get fails under a Dart-only SDK — the root cause described in #2463. The job therefore uses the repository's setup-dart action, which installs Flutter. If the root pubspec is later split as proposed there, the job can drop to a lightweight Dart SDK by swapping that one step; there is a comment at the step saying so.

First commit

dart analyze --fatal-infos needs the three unnecessary_library_directive infos resolved first. #2439 is already resolving the same three, and I matched its approach rather than inventing a second one: the two libraries in a2ui_core get the doc comment they were missing, a2ui_agent's bare directive is removed. reactivity.dart and a2ui_agent.dart come out byte-identical to that PR, so they merge with no conflict; a2ui_core.dart conflicts only in the wording of the doc comment. If #2439 lands first I will rebase and keep its wording — the workflow itself does not conflict with anything.

Verification

I cannot run GitHub Actions locally, so I ran the workflow's own steps, including the matrix-generation script verbatim:

matrix=[{"name":"dart_a2ui_agent","path":"dart/a2ui_agent"},{"name":"dart_a2ui_core","path":"dart/a2ui_core"}]

dart/a2ui_agent | format:OK | analyze --fatal-infos:OK | 00:00 +1: All tests passed!
dart/a2ui_core  | format:OK | analyze --fatal-infos:OK | 00:00 +74: All tests passed!

The workflow file parses as YAML, carries the license header (fix_licenses.py --check does not flag it) and is Prettier-clean.

A note on the checklist below

As in #2491, I have not touched the packages' CHANGELOG.md files, so the changelog health check will flag this PR. #2439 already adds a ## 0.2.0 section to both, and a competing section here would only give that PR a conflict to resolve. The change in this PR is a doc comment and a removed directive — no API or behaviour change — but I am glad to add entries wherever you prefer.

Pre-launch Checklist

One time:

• I signed the CLA.
• I read the Contributors Guide.
• I read the Style Guide.
• I have built and run at least one sample.

For this PR:

• I have updated the relevant CHANGELOG.md file. (see the note above)
• I updated/added relevant documentation. (library doc comments; the workflow explains its own Flutter dependency)
• My code changes (if any) have tests. (the change is test coverage; the packages' existing suites now run in CI)
• If my branch is on a fork, I have verified that scripts/e2e_test.sh passes. (no product code changes; both Dart suites pass)

[gemini-code-assist]

Code Review

This pull request cleans up the Dart library declarations by removing an unnecessary empty library directive in a2ui_agent.dart and adding descriptive library-level documentation comments to a2ui_core.dart and reactivity.dart. There are no review comments, so I have no feedback to provide.

[diegolopezrm]

Rebased onto main after #2439. Two changes to what this PR contains.

The library-directive commit is gone. #2439 resolved all three the same way, so dart analyze --fatal-infos is already clean on main without it. This PR is now the workflow file alone, plus the formatting fix below.

It picked up a two-file formatting fix, which is worth a sentence because it is the first thing the new job found. dart format --set-exit-if-changed over dart/ fails on main today:

Changed test/conformance/message_processor_conformance_test.dart
Changed test/validator_test.dart

Both arrived with #2439, and neither is anyone's oversight: fix_format.sh formats samples/client/flutter and renderers/flutter, never dart/, so nothing has ever held these packages to a format. The fix is pure dart format output — 10 insertions, 6 deletions — and identical under --language-version=3.10, so it is not a language-version difference. Without it the job this PR adds would go red on its first run against main.

That is the argument for the PR in miniature: the packages published from this repository have had no formatting, analysis or test gate, and the gap shows up the moment one is applied.

Verified after the rebase: dart format clean, dart analyze --fatal-infos clean, and dart test green in both packages — 293 in a2ui_core (up from 74 before #2439) and 1 in a2ui_agent.

[Varun-S10]

Hi @gspencergoog, I have pulled and verified the changes locally, and all tests pass as expected. Could you please review this PR?

[gspencergoog]

This will skip dart files in other parts of the tree. There currently aren't any, but that doesn't mean there couldn't be (imagine a tool implemented in Dart, for instance), and it is a monorepo, so the top level directory is also excluded by this. I'd search the whole tree.

[gspencergoog]

Actually, the automation added by this PR is already addressed in the Flutter CI, and presubmit lint/format checks.

What is being checked here that isn't already being checked in the other ones?

[diegolopezrm]

You're right, and thanks for pushing back on it.

#2439 added dart to the matrix in flutter_packages_test.yml yesterday, so formatting, flutter analyze --fatal-infos and the tests already run over both packages on stable and beta, hourly. That is everything this PR was adding, and it does it better. Closing it.

On the wider point: I'm between jobs at the moment and putting the time into this repo, so I'm glad to take on whatever is actually useful — triage, reproducing issues, filling gaps in test coverage, the unglamorous parts. Just point me at it.