[flutter-gold] Consider neutral checks completed (#5036)

Fixes flutter/flutter#185832

This PR improves how Flutter Gold status updates are computed by
accounting for completed checks that end in a `NEUTRAL` conclusion
(alongside `SUCCESS`). It also streamlines logging and fortifies the
check status evaluation.

* Updates the evaluation logic so that PR checks ending in NEUTRAL are
no longer grouped alongside incomplete or failing tests.
* Added explicit status verification for check runs. If a check run does
not have the status 'COMPLETED', it is now safely and reliably
classified as incomplete.
* Moved the log.debug statement to only capture check runs that are
truly incomplete or failing, significantly reducing log output noise.

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read the [Flutter Style Guide] _recently_, and have followed its
advice.
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

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---------

Co-authored-by: John "codefu" McDole <john@mcdole.org>
Co-authored-by: John McDole <codefu@google.com>

Author: Piinks

app_dart/lib/src/request_handlers/push_gold_status_to_github.dart

@@ -136,7 +136,6 @@ final class PushGoldStatusToGithub extends ApiRequestHandler {
       checkRuns = checkRuns ?? <Map<String, dynamic>>[];
       log.debug('This PR has ${checkRuns.length} checks.');
       for (var checkRun in checkRuns) {
-        log.debug('Check run: $checkRun');
         final name = checkRun['name'].toLowerCase() as String;
         if (slug == Config.flutterSlug) {
           if (const <String>[
@@ -160,8 +159,13 @@ final class PushGoldStatusToGithub extends ApiRequestHandler {
             runsGoldenFileTests = true;
           }
         }
-        if (checkRun['conclusion'] == null ||
-            checkRun['conclusion'].toUpperCase() != 'SUCCESS') {
+        const successfulConclusion = {'SUCCESS', 'NEUTRAL'};
+
+        if (checkRun['status']?.toUpperCase() != 'COMPLETED' ||
+            !successfulConclusion.contains(
+              checkRun['conclusion']?.toUpperCase(),
+            )) {
+          log.debug('Incomplete check run: $checkRun');
           incompleteChecks.add(name);
         }
       }

app_dart/test/request_handlers/push_gold_status_to_github_test.dart

@@ -361,6 +361,64 @@ void main() {
         );
       });
 
+      test(
+        'same commit, neutral checks complete, last status complete',
+        () async {
+          // Same commit
+          final pr = newPullRequest(123, 'abc', 'master');
+          prsFromGitHub = <PullRequest>[pr];
+
+          firestore.putDocument(
+            newGithubGoldStatus(
+              slug,
+              pr,
+              GithubGoldStatus.statusCompleted,
+              'abc',
+              config.flutterGoldSuccessValue!,
+            ),
+          );
+
+          // Neutral checks complete
+          checkRuns = <dynamic>[
+            <String, String>{
+              'name': 'framework',
+              'status': 'completed',
+              'conclusion': 'neutral',
+            },
+            <String, String>{
+              'name': 'web engine',
+              'status': 'completed',
+              'conclusion': 'neutral',
+            },
+          ];
+
+          final body = await tester.get(handler);
+          expect(body, same(Response.emptyOk));
+          expect(
+            firestore,
+            existsInStorage(fs.GithubGoldStatus.metadata, [
+              isGithubGoldStatus.hasUpdates(0),
+            ]),
+          );
+          expect(log, hasNoWarningsOrHigher);
+
+          // Should not apply labels or make comments
+          verifyNever(
+            issuesService.addLabelsToIssue(slug, pr.number!, <String>[
+              kGoldenFileLabel,
+            ]),
+          );
+
+          verifyNever(
+            issuesService.createComment(
+              slug,
+              pr.number!,
+              argThat(contains(config.flutterGoldCommentID(pr))),
+            ),
+          );
+        },
+      );
+
       test(
         'same commit, checks complete, last status & gold status is running/awaiting triage, should not comment',
         () async {
@@ -1160,7 +1218,7 @@ void main() {
         checkRuns = <dynamic>[
           <String, String>{
             'name': 'framework',
-            'completed': 'in_progress',
+            'status': 'completed',
             'conclusion': 'success',
           },
         ];