feat(app_dart): fall back to ciStaging in GetPresubmitGuard when no guards found

app_dart/lib/src/model/common/checks_extension.dart

@@ -69,4 +69,14 @@ extension ChecksExtension on TaskStatus {
       _ => .failed,
     };
   }
+
+  /// Converts a [TaskConclusion] to a [TaskStatus].
+  static TaskStatus fromTaskConclusion(TaskConclusion conclusion) {
+    return switch (conclusion) {
+      TaskConclusion.unknown || TaskConclusion.failure => TaskStatus.failed,
+      TaskConclusion.scheduled => TaskStatus.waitingForBackfill,
+      TaskConclusion.success => TaskStatus.succeeded,
+      TaskConclusion.neutral => TaskStatus.neutral,
+    };
+  }
 }

app_dart/lib/src/model/firestore/ci_staging.dart

@@ -112,6 +112,22 @@ final class CiStaging extends AppDocument<CiStaging> {
     return CiStaging.fromDocument(document);
   }
 
+  /// Queries for [CiStaging] records by [slug] and [sha].
+  ///
+  /// This is used to get both `_engine` and `_fusion` documents.
+  static Future<List<CiStaging>> getCiStagingForCommitSha({
+    required FirestoreService firestoreService,
+    required RepositorySlug slug,
+    required String sha,
+  }) async {
+    final filterMap = {
+      '$fieldRepoFullPath =': slug.fullName,
+      '$fieldCommitSha =': sha,
+    };
+    final documents = await firestoreService.query(_collectionId, filterMap);
+    return documents.map(CiStaging.fromDocument).toList();
+  }
+
   /// Create [CiStaging] from a Commit Document.
   CiStaging.fromDocument(Document other) {
     this

app_dart/lib/src/request_handlers/get_presubmit_guard.dart

@@ -3,13 +3,16 @@
 // found in the LICENSE file.
 
 import 'dart:async';
+import 'dart:convert';
 
 import 'package:cocoon_common/guard_status.dart';
 import 'package:cocoon_common/rpc_model.dart' as rpc_model;
 import 'package:github/github.dart';
 import 'package:meta/meta.dart';
 
 import '../../cocoon_service.dart';
+import '../model/common/checks_extension.dart';
+import '../model/firestore/ci_staging.dart';
 import '../request_handling/public_api_request_handler.dart';
 import '../service/firestore/unified_check_run.dart';
 
@@ -95,9 +98,7 @@ final class GetPresubmitGuard extends PublicApiRequestHandler {
     );
 
     if (guards.isEmpty) {
-      return Response.json({
-        'error': 'No guard found for slug $slug and sha $sha',
-      }, statusCode: HttpStatus.notFound);
+      return _getCiStagingFallback(slug, sha);
     }
 
     // Consolidate metadata from the first record.
@@ -134,4 +135,78 @@ final class GetPresubmitGuard extends PublicApiRequestHandler {
 
     return Response.json(response);
   }
+
+  Future<Response> _getCiStagingFallback(
+    RepositorySlug slug,
+    String sha,
+  ) async {
+    final ciStagings = await CiStaging.getCiStagingForCommitSha(
+      firestoreService: _firestore,
+      slug: slug,
+      sha: sha,
+    );
+
+    if (ciStagings.isEmpty) {
+      return Response.json({
+        'error': 'No guard found for slug $slug and sha $sha',
+      }, statusCode: HttpStatus.notFound);
+    }
+
+    final totalFailed = ciStagings.fold<int>(0, (sum, g) => sum + g.failed);
+    final totalRemaining = ciStagings.fold<int>(
+      0,
+      (sum, g) => sum + g.remaining,
+    );
+    final totalBuilds = ciStagings.fold<int>(0, (sum, g) => sum + g.total);
+
+    final guardStatus = GuardStatus.calculate(
+      failedBuilds: totalFailed,
+      remainingBuilds: totalRemaining,
+      totalBuilds: totalBuilds,
+    );
+
+    var checkRunId = -1;
+    final guardJsonStr = ciStagings.first.checkRunGuard;
+    if (guardJsonStr.isNotEmpty) {
+      try {
+        // Try to extract the check-run id from the json string.
+        final guardJson = jsonDecode(guardJsonStr) as Map<String, Object?>;
+        checkRunId = guardJson['id'] as int? ?? 0;
+      } catch (_) {
+        // ignore
+      }
+    }
+
+    var prNum = 0;
+    var author = '';
+
+    final prInfo = await PrCheckRuns.findPullRequestForSha(_firestore, sha);
+    if (prInfo != null) {
+      prNum = prInfo.number ?? 0;
+      author = prInfo.user?.login ?? '';
+    }
+
+    final response = rpc_model.PresubmitGuardResponse(
+      prNum: prNum,
+      checkRunId: checkRunId,
+      author: author,
+      guardStatus: guardStatus,
+      enableGeminiLogAnalysis: config.flags.enableGeminiLogAnalysis,
+      stages: [
+        for (final g in ciStagings)
+          rpc_model.PresubmitGuardStage(
+            name: g.stage?.name ?? 'unknown',
+            createdAt:
+                DateTime.tryParse(g.createTime ?? '')?.millisecondsSinceEpoch ??
+                0,
+            jobs: {
+              for (final MapEntry(:key, :value) in g.checkRuns.entries)
+                key: ChecksExtension.fromTaskConclusion(value),
+            },
+          ),
+      ],
+    );
+
+    return Response.json(response);
+  }
 }

app_dart/test/model/common/checks_extension_test.dart

@@ -38,6 +38,29 @@ void main() {
         TaskStatus.neutral,
       );
     });
+
+    test('fromTaskConclusion mapping', () {
+      expect(
+        ChecksExtension.fromTaskConclusion(TaskConclusion.success),
+        TaskStatus.succeeded,
+      );
+      expect(
+        ChecksExtension.fromTaskConclusion(TaskConclusion.neutral),
+        TaskStatus.neutral,
+      );
+      expect(
+        ChecksExtension.fromTaskConclusion(TaskConclusion.failure),
+        TaskStatus.failed,
+      );
+      expect(
+        ChecksExtension.fromTaskConclusion(TaskConclusion.scheduled),
+        TaskStatus.waitingForBackfill,
+      );
+      expect(
+        ChecksExtension.fromTaskConclusion(TaskConclusion.unknown),
+        TaskStatus.failed,
+      );
+    });
   });
 
   group('TaskConclusion', () {

app_dart/test/request_handlers/get_presubmit_guard_test.dart

@@ -11,9 +11,12 @@ import 'package:cocoon_common/task_status.dart';
 import 'package:cocoon_integration_test/testing.dart';
 import 'package:cocoon_server_test/test_logging.dart';
 import 'package:cocoon_service/src/model/firestore/base.dart';
+import 'package:cocoon_service/src/model/firestore/ci_staging.dart';
 import 'package:cocoon_service/src/request_handlers/get_presubmit_guard.dart';
 import 'package:cocoon_service/src/request_handling/exceptions.dart';
+import 'package:cocoon_service/src/service/firestore.dart';
 import 'package:github/github.dart';
+import 'package:googleapis/firestore/v1.dart' hide Status;
 import 'package:test/test.dart';
 
 import '../src/request_handling/request_handler_tester.dart';
@@ -213,4 +216,51 @@ void main() {
     final response = await tester.get(handler);
     expect(response.statusCode, HttpStatus.ok);
   });
+
+  test('falls back to ciStaging if no guards found', () async {
+    final slug = RepositorySlug('flutter', 'flutter');
+    const sha = 'abc';
+
+    final staging = CiStaging.fromDocument(
+      Document(
+        name: CiStaging.documentNameFor(
+          slug: slug,
+          sha: sha,
+          stage: CiStage.fusionEngineBuild,
+        ),
+        fields: {
+          CiStaging.kTotalField: 2.toValue(),
+          CiStaging.kRemainingField: 1.toValue(),
+          CiStaging.kFailedField: 0.toValue(),
+          CiStaging.kCheckRunGuardField: '{"id": 0}'.toValue(),
+          CiStaging.fieldRepoFullPath: slug.fullName.toValue(),
+          CiStaging.fieldCommitSha: sha.toValue(),
+          CiStaging.fieldStage: CiStage.fusionEngineBuild.name.toValue(),
+          'job1': TaskConclusion.success.name.toValue(),
+          'job2': TaskConclusion.scheduled.name.toValue(),
+        },
+      ),
+    );
+
+    firestore.putDocuments([staging]);
+
+    tester.request = FakeHttpRequest(
+      queryParametersValue: {
+        GetPresubmitGuard.kOwnerParam: 'flutter',
+        GetPresubmitGuard.kRepoParam: 'flutter',
+        GetPresubmitGuard.kShaParam: sha,
+      },
+    );
+
+    final result = (await getResponse())!;
+    expect(result.prNum, 0);
+    expect(result.checkRunId, 0);
+    expect(result.guardStatus, GuardStatus.inProgress);
+    expect(result.stages.length, 1);
+    expect(result.stages.first.name, CiStage.fusionEngineBuild.name);
+    expect(result.stages.first.jobs, {
+      'job1': TaskStatus.succeeded,
+      'job2': TaskStatus.waitingForBackfill,
+    });
+  });
 }

dashboard/test/views/presubmit_view_test.dart

@@ -1183,8 +1183,9 @@ void main() {
           for (var i = 0; i < 20; i++) {
             await tester.pump();
             await Future<void>.delayed(const Duration(milliseconds: 50));
-            if (find.textContaining('linux_analyze').evaluate().isNotEmpty)
+            if (find.textContaining('linux_analyze').evaluate().isNotEmpty) {
               break;
+            }
           }
         });
         await tester.pump();
@@ -1243,8 +1244,9 @@ void main() {
           for (var i = 0; i < 20; i++) {
             await tester.pump();
             await Future<void>.delayed(const Duration(milliseconds: 50));
-            if (find.textContaining('linux_analyze').evaluate().isNotEmpty)
+            if (find.textContaining('linux_analyze').evaluate().isNotEmpty) {
               break;
+            }
           }
         });
         await tester.pump();