Use any branch with commits in the last week as a backfill signal.

app_dart/lib/server.dart

@@ -131,14 +131,6 @@ Server createServer({
       ciYamlFetcher: ciYamlFetcher,
       luciBuildService: luciBuildService,
       firestore: firestore,
-      branchService: branchService,
-    ),
-    '/api/v2/scheduler/batch-backfiller': BatchBackfiller(
-      config: config,
-      ciYamlFetcher: ciYamlFetcher,
-      luciBuildService: luciBuildService,
-      firestore: firestore,
-      branchService: branchService,
     ),
     '/api/v2/scheduler/batch-request-subscription':
         SchedulerRequestSubscription(

app_dart/lib/src/request_handlers/scheduler/batch_backfiller.dart

@@ -4,7 +4,7 @@
 
 import 'dart:math';
 
-import 'package:cocoon_common/is_release_branch.dart';
+import 'package:cocoon_common/core_extensions.dart';
 import 'package:cocoon_common/task_status.dart';
 import 'package:cocoon_server/logging.dart';
 import 'package:github/github.dart';
@@ -32,69 +32,60 @@ final class BatchBackfiller extends RequestHandler {
     required CiYamlFetcher ciYamlFetcher,
     required LuciBuildService luciBuildService,
     required FirestoreService firestore,
-    required BranchService branchService,
     BackfillStrategy backfillerStrategy = const DefaultBackfillStrategy(),
+    @visibleForTesting DateTime Function() now = DateTime.now,
   }) : _ciYamlFetcher = ciYamlFetcher,
        _luciBuildService = luciBuildService,
        _backfillerStrategy = backfillerStrategy,
        _firestore = firestore,
-       _branchService = branchService;
+       _now = now;
 
   final LuciBuildService _luciBuildService;
   final CiYamlFetcher _ciYamlFetcher;
   final BackfillStrategy _backfillerStrategy;
   final FirestoreService _firestore;
-  final BranchService _branchService;
+  final DateTime Function() _now;
 
   @override
   Future<Response> get(Request request) async {
-    await _backfillReleaseBranch(Config.flutterSlug);
-    await Future.forEach(config.supportedRepos, _backfillDefaultBranch);
-    await _backfillExperimentalBranch(Config.flutterSlug);
-    return Response.emptyOk;
-  }
-
-  // TODO(matanlurey): Remove or make a formal supported feature.
-  //
-  // Hardcodes running a branch named `ios-experimental`, which is being tried
-  // by the iOS team to do MacOS 15.5 validation. It will appear similar to
-  // any other branch, but use lower-priority scheduling.
-  //
-  // See https://github.com/flutter/flutter/issues/168738.
-  Future<void> _backfillExperimentalBranch(RepositorySlug slug) async {
-    log.debug('Running experimental branch backfiller for "$slug"');
-    final fsGrid = await _firestore.queryRecentCommitsAndTasks(
-      slug,
-      commitLimit: config.flags.backfillerCommitLimit,
-      branch: 'ios-experimental',
-    );
-    await _doBackfillFrom(slug, fsGrid, forceLowPriority: true);
-  }
+    log.debug('Finding all branches eligible for backfilling');
+    final branches = <(RepositorySlug, String)>{};
+    for (final repo in config.supportedRepos) {
+      // Always include the default branch.
+      final defaultBranch = Config.defaultBranch(repo);
+      branches.add((repo, defaultBranch));
 
-  Future<void> _backfillReleaseBranch(RepositorySlug slug) async {
-    log.debug('Running release branch backfiller for "$slug"');
-    final branches = await _branchService.getReleaseBranches(slug: slug);
-    for (final branch in branches) {
-      if (!isReleaseCandidateBranch(branchName: branch.reference)) {
-        continue;
-      }
-      final fsGrid = await _firestore.queryRecentCommitsAndTasks(
-        slug,
-        commitLimit: config.flags.backfillerCommitLimit,
-        branch: branch.reference,
+      // Look for any branch that has received a commit in the last 7 days.
+      final commits = await _firestore.queryRecentCommits(
+        slug: repo,
+        limit: null,
+        created: TimeRange.after(_now().subtract(const Duration(days: 7))),
       );
-      await _doBackfillFrom(slug, fsGrid);
+      for (final commit in commits) {
+        branches.add((repo, commit.branch));
+      }
     }
-  }
 
-  Future<void> _backfillDefaultBranch(RepositorySlug slug) async {
-    log.debug('Running default branch backfiller for "$slug"');
-    final fsGrid = await _firestore.queryRecentCommitsAndTasks(
-      slug,
-      commitLimit: config.flags.backfillerCommitLimit,
-      branch: Config.defaultBranch(slug),
+    log.debug(
+      'Found ${branches.length} branches eligible for backfilling:\n'
+      '${branches.join('\n')}',
     );
-    return await _doBackfillFrom(slug, fsGrid);
+
+    await Future.forEach(branches, (branch) async {
+      final (slug, branchName) = branch;
+      log.debug('Backfilling ${slug.fullName} -> $branchName');
+      await _doBackfillFrom(
+        slug,
+        await _firestore.queryRecentCommitsAndTasks(
+          slug,
+          commitLimit: config.flags.backfillerCommitLimit,
+          branch: branchName,
+        ),
+      );
+    });
+    return Response.json({
+      'branches': [...branches.map((e) => '$e')],
+    });
   }
 
   Future<void> _doBackfillFrom(
@@ -103,7 +94,7 @@ final class BatchBackfiller extends RequestHandler {
     bool forceLowPriority = false,
   }) async {
     if (fsGrid.isEmpty) {
-      log.warn('No commits to backfill');
+      log.info('No commits to backfill');
       return;
     }
 

app_dart/lib/src/service/firestore.dart

@@ -68,39 +68,37 @@ mixin FirestoreQueries {
     Transaction? transaction,
   });
 
-  static Map<String, String> _filterByTimeRAnge(
+  static Map<String, Object> _filterByTimeRAnge(
     String fieldName,
     TimeRange range,
   ) {
     return switch (range) {
       IndefiniteTimeRange() => const {},
       SpecificTimeRange(:final start, :final end, :final exclusive) => {
         if (start != null)
-          '$fieldName ${exclusive ? '>' : '>='}':
-              '${start.millisecondsSinceEpoch}',
+          '$fieldName ${exclusive ? '>' : '>='}': start.millisecondsSinceEpoch,
         if (end != null)
-          '$fieldName ${exclusive ? '<' : '<='}':
-              '${end.millisecondsSinceEpoch}',
+          '$fieldName ${exclusive ? '<' : '<='}': end.millisecondsSinceEpoch,
       },
     };
   }
 
   /// Queries for recent commits.
   ///
-  /// The [limit] argument specifies the maximum number of commits to retrieve.
+  /// If [limit] is `null`, all commits are returned.
   ///
-  /// The returned commits will be ordered by most recent [Commit.timestamp].
+  /// The returned commits will be ordered by most recent
+  /// [Commit.createTimestamp].
   Future<List<Commit>> queryRecentCommits({
-    int limit = 100,
+    required int? limit,
+    required RepositorySlug slug,
     TimeRange? created,
     String? branch,
-    required RepositorySlug slug,
   }) async {
-    branch ??= Config.defaultBranch(slug);
     created ??= TimeRange.indefinite;
     final filterMap = <String, Object>{
-      '${Commit.fieldBranch} =': branch,
       '${Commit.fieldRepositoryPath} =': slug.fullName,
+      if (branch != null) '${Commit.fieldBranch} =': branch,
       ..._filterByTimeRAnge(Commit.fieldCreateTimestamp, created),
     };
     final orderMap = <String, String>{

app_dart/test/request_handlers/scheduler/batch_backfiller_test.dart

@@ -2,7 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:cocoon_common/rpc_model.dart' as rpc;
 import 'package:cocoon_common/task_status.dart';
 import 'package:cocoon_server_test/test_logging.dart';
 import 'package:cocoon_service/src/model/commit_ref.dart';
@@ -13,7 +12,6 @@ import 'package:cocoon_service/src/service/config.dart';
 import 'package:cocoon_service/src/service/luci_build_service.dart';
 import 'package:cocoon_service/src/service/luci_build_service/pending_task.dart';
 import 'package:collection/collection.dart';
-import 'package:github/github.dart';
 import 'package:mockito/mockito.dart';
 import 'package:test/test.dart';
 
@@ -22,7 +20,6 @@ import '../../src/request_handling/request_handler_tester.dart';
 import '../../src/service/fake_ci_yaml_fetcher.dart';
 import '../../src/service/fake_firestore_service.dart';
 import '../../src/utilities/entity_generators.dart';
-import '../../src/utilities/mocks.mocks.dart';
 
 void main() {
   useTestLoggerPerTest();
@@ -31,14 +28,12 @@ void main() {
   late BatchBackfiller handler;
 
   // Dependencies.
+  final fakeNow = DateTime(2025, 1, 1);
   late FakeConfig config;
   late FakeFirestoreService firestore;
   late FakeCiYamlFetcher ciYamlFetcher;
   late _FakeLuciBuildService fakeLuciBuildService;
 
-  // Used to implement BranchService.getBranches.
-  late List<rpc.Branch>? branchesForRepository;
-
   // Fixture.
   late RequestHandlerTester tester;
 
@@ -52,28 +47,13 @@ void main() {
     ciYamlFetcher = FakeCiYamlFetcher();
     fakeLuciBuildService = _FakeLuciBuildService();
 
-    final branchService = MockBranchService();
-    branchesForRepository = [];
-    when(branchService.getReleaseBranches(slug: anyNamed('slug'))).thenAnswer((
-      i,
-    ) async {
-      final slug = i.namedArguments[#slug] as RepositorySlug;
-      return branchesForRepository ??
-          [
-            rpc.Branch(
-              channel: Config.defaultBranch(slug),
-              reference: Config.defaultBranch(slug),
-            ),
-          ];
-    });
-
     handler = BatchBackfiller(
       config: config,
       ciYamlFetcher: ciYamlFetcher,
       luciBuildService: fakeLuciBuildService,
       backfillerStrategy: const _NaiveBackfillStrategy(),
       firestore: firestore,
-      branchService: branchService,
+      now: () => fakeNow,
     );
 
     tester = RequestHandlerTester();
@@ -119,6 +99,7 @@ void main() {
       '''
     enabled_branches:
       - master
+      - $branch
 
     targets:
       - name: Linux 0
@@ -133,13 +114,14 @@ void main() {
       engine: '''
     enabled_branches:
       - master
+      - $branch
 
     targets:
       - name: Engine 0
     ''',
     );
 
-    var date = DateTime(2025, 1, 1);
+    var date = fakeNow;
     for (final (i, row) in statuses.indexed) {
       final fsCommit = generateFirestoreCommit(
         i,
@@ -286,11 +268,6 @@ void main() {
   });
 
   test('backfills release candidate branches', () async {
-    branchesForRepository = [
-      rpc.Branch(channel: 'master', reference: 'master'),
-      rpc.Branch(channel: 'beta', reference: 'flutter-3.32-candidate.0'),
-    ];
-
     // dart format off
     await fillStorageAndSetCiYaml([
       [$N, $I, $F, $S],
@@ -356,10 +333,6 @@ void main() {
 
   // https://github.com/flutter/flutter/issues/168738
   test('schedules low-priority targets for "ios-experimental"', () async {
-    branchesForRepository = [
-      // Intentionally left blank.
-    ];
-
     // dart format off
     await fillStorageAndSetCiYaml([
       [$N, $I, $F, $S],

cron.yaml

@@ -12,7 +12,7 @@ cron:
   schedule: every 1 hours
 
 - description: backfills builds
-  url: /api/v2/scheduler/batch-backfiller
+  url: /api/scheduler/batch-backfiller
   schedule: every 5 minutes
 
 - description: sends build status to GitHub to annotate flutter PRs and commits