[WIP] Adds github action for creating batch release

.github/workflows/batch_release_pr.yml

@@ -0,0 +1,39 @@
+name: "Creates Batch Release for go_router package"
+
+on:
+  repository_dispatch:
+    types: [batch_release_pr]
+
+jobs:
+  create_release_pr:
+    runs-on: ubuntu-latest
+    env:
+      BRANCH_NAME: ${{ github.event.client_payload.package }}-${{ github.run_id }}-${{ github.run_attempt }}
+    steps:
+      - name: checkout repository
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8
+      - name: Set up tools
+        run: dart pub get
+        working-directory: ${{ github.workspace }}/script/tool
+    # Give some time for LUCI checks to start becoming populated.
+    # Because of latency in Github Webhooks, we need to wait for a while
+    # before being able to look at checks scheduled by LUCI.
+      - name: Give webhooks a minute
+        run: sleep 60s
+        shell: bash
+      - name: create batch release PR
+        run: |
+          git config --global user.name ${{ secrets.USER_NAME }}
+          git config --global user.email ${{ secrets.USER_EMAIL }}
+          dart ./script/tool/lib/src/main.dart branch-for-batch-release --packages=${{ github.event.client_payload.package }} --branch=${{ env.BRANCH_NAME }}"
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v7
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          commit-message: "Batch release PR for ${{ github.event.client_payload.package }} package"
+          title: "Batch Release PR for ${{ github.event.client_payload.package }} package"
+          body: "This PR was created automatically to batch release the ${{ github.event.client_payload.package }} package."
+          branch: ${{ env.BRANCH_NAME }}
+          base: release
+
+

.github/workflows/go_router_batch.yml

@@ -0,0 +1,16 @@
+name: "Creates Batch Release for go_router package"
+
+on:
+  schedule:
+  - cron: "0 0 * * *"
+
+jobs:
+  dispatch_release_pr:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Repository Dispatch
+        uses: peter-evans/repository-dispatch@v4
+        with:
+          token: "${{ secrets.GITHUB_TOKEN }}"
+          event-type: batch_release_pr
+          client-payload: '{"package": "go_router"}'

packages/go_router/pending_changelogs/template.yaml

@@ -0,0 +1,6 @@
+# Use this file as template to draft a unreleased changelog file.
+# Make a copy of this file in the same directory, rename it, and fill in the details.
+changelog: |
+  - Can include a list of changes.
+  - with markdown supported.
+version: <major|minor|patch|skip>

packages/go_router/pending_changelogs/test_only_1.yaml

@@ -0,0 +1,6 @@
+# This file is for test purposes only.
+# TODO(chuntai): remove this file before publishing.
+changelog: |
+  - Added 'batch' option to CI config for go_router package.
+  - Updated GitHub Actions workflow for batch releases of go_router.
+version: major

packages/go_router/pending_changelogs/test_only_2.yaml

@@ -0,0 +1,6 @@
+# This file is for test purposes only.
+# TODO(chuntai): remove this file before publishing.
+changelog: |
+  - Added 'batch' option to CI config for go_router package.
+  - Updated GitHub Actions workflow for batch releases of go_router.
+version: major

script/tool/lib/src/branch_for_batch_release_command.dart

@@ -0,0 +1,311 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:io' as io;
+import 'dart:math' as math;
+
+import 'package:file/file.dart';
+import 'package:git/git.dart';
+import 'package:pub_semver/pub_semver.dart';
+import 'package:yaml/yaml.dart';
+import 'package:yaml_edit/yaml_edit.dart';
+
+import 'common/core.dart';
+import 'common/output_utils.dart';
+import 'common/package_command.dart';
+import 'common/repository_package.dart';
+
+const int _kExitPackageMalformed = 2;
+const int _kGitFailedToPush = 3;
+
+const String _kTemplateFileName = 'template.yaml';
+
+/// A command to create a remote branch with release changes for a single package.
+class BranchForBatchReleaseCommand extends PackageCommand {
+  /// Creates a new `branch-for-batch-release` command.
+  BranchForBatchReleaseCommand(
+    super.packagesDir, {
+    super.processRunner,
+    super.platform,
+    super.gitDir,
+  }) {
+    argParser.addOption(
+      'branch',
+      mandatory: true,
+      abbr: 'b',
+      help: 'The branch to push the release PR to.',
+    );
+  }
+
+  @override
+  final String name = 'branch-for-batch-release';
+
+  @override
+  final String description = 'Creates a release PR for a single package.';
+
+  @override
+  Future<void> run() async {
+    final String branchName = argResults!['branch'] as String;
+
+    final List<RepositoryPackage> packages = await getTargetPackages()
+        .map((PackageEnumerationEntry e) => e.package)
+        .toList();
+    if (packages.length != 1) {
+      printError('Exactly one package must be specified.');
+      throw ToolExit(2);
+    }
+    final RepositoryPackage package = packages.single;
+
+    final GitDir repository = await gitDir;
+
+    print('Parsing package "${package.displayName}"...');
+    final PendingChangelogs pendingChangelogs =
+        await _getPendingChangelogs(package);
+    if (pendingChangelogs.entries.isEmpty) {
+      print('No pending changelogs found for ${package.displayName}.');
+      return;
+    }
+
+    final Pubspec pubspec =
+        Pubspec.parse(package.pubspecFile.readAsStringSync());
+    final ReleaseInfo releaseInfo =
+        _getReleaseInfo(pendingChangelogs.entries, pubspec.version!);
+
+    if (releaseInfo.newVersion == null) {
+      print('No version change specified in pending changelogs for '
+          '${package.displayName}.');
+      return;
+    }
+
+    print('Creating and pushing release branch...');
+    await _pushBranch(
+      repository: repository,
+      package: package,
+      branchName: branchName,
+      pendingChangelogFiles: pendingChangelogs.files,
+      releaseInfo: releaseInfo,
+    );
+  }
+
+  Future<PendingChangelogs> _getPendingChangelogs(
+      RepositoryPackage package) async {
+    final Directory pendingChangelogsDir =
+        package.directory.childDirectory('pending_changelogs');
+    if (!pendingChangelogsDir.existsSync()) {
+      printError(
+          'No pending_changelogs folder found for ${package.displayName}.');
+      throw ToolExit(_kExitPackageMalformed);
+    }
+    final List<File> pendingChangelogFiles = pendingChangelogsDir
+        .listSync()
+        .whereType<File>()
+        .where((File f) =>
+            f.basename.endsWith('.yaml') && f.basename != _kTemplateFileName)
+        .toList();
+    try {
+      final List<PendingChangelogEntry> entries = pendingChangelogFiles
+          .map<PendingChangelogEntry>(
+              (File f) => PendingChangelogEntry.parse(f.readAsStringSync()))
+          .toList();
+      return PendingChangelogs(entries, pendingChangelogFiles);
+    } on FormatException catch (e) {
+      printError('Malformed pending changelog file: $e');
+      throw ToolExit(_kExitPackageMalformed);
+    }
+  }
+
+  ReleaseInfo _getReleaseInfo(
+      List<PendingChangelogEntry> pendingChangelogEntries, Version oldVersion) {
+    final List<String> changelogs = <String>[];
+    int versionIndex = VersionChange.skip.index;
+    for (final PendingChangelogEntry entry in pendingChangelogEntries) {
+      changelogs.add(entry.changelog);
+      versionIndex = math.min(versionIndex, entry.version.index);
+    }
+    final VersionChange effectiveVersionChange =
+        VersionChange.values[versionIndex];
+
+    Version? newVersion;
+    switch (effectiveVersionChange) {
+      case VersionChange.skip:
+        break;
+      case VersionChange.major:
+        newVersion = Version(
+          oldVersion.major + 1,
+          0,
+          0,
+        );
+      case VersionChange.minor:
+        newVersion = Version(
+          oldVersion.major,
+          oldVersion.minor + 1,
+          0,
+        );
+      case VersionChange.patch:
+        newVersion = Version(
+          oldVersion.major,
+          oldVersion.minor,
+          oldVersion.patch + 1,
+        );
+    }
+    return ReleaseInfo(newVersion, changelogs);
+  }
+
+  Future<void> _pushBranch({
+    required GitDir repository,
+    required RepositoryPackage package,
+    required String branchName,
+    required List<File> pendingChangelogFiles,
+    required ReleaseInfo releaseInfo,
+  }) async {
+    print('  Creating new branch "$branchName"...');
+    final io.ProcessResult checkoutResult =
+        await repository.runCommand(<String>['checkout', '-b', branchName]);
+    if (checkoutResult.exitCode != 0) {
+      printError(
+          'Failed to create branch $branchName: ${checkoutResult.stderr}');
+      throw ToolExit(_kGitFailedToPush);
+    }
+
+    print('  Updating pubspec.yaml to version ${releaseInfo.newVersion}...');
+    // Update pubspec.yaml.
+    final YamlEditor editablePubspec =
+        YamlEditor(package.pubspecFile.readAsStringSync());
+    editablePubspec
+        .update(<String>['version'], releaseInfo.newVersion.toString());
+    package.pubspecFile.writeAsStringSync(editablePubspec.toString());
+
+    print('  Updating CHANGELOG.md...');
+    // Update CHANGELOG.md.
+    final String newHeader = '## ${releaseInfo.newVersion}';
+    final List<String> newEntries = releaseInfo.changelogs;
+
+    final String oldChangelogContent = package.changelogFile.readAsStringSync();
+    final StringBuffer newChangelog = StringBuffer();
+
+    newChangelog.writeln(newHeader);
+    newChangelog.writeln();
+    newChangelog.writeln(newEntries.join('\n'));
+    newChangelog.writeln();
+    newChangelog.write(oldChangelogContent);
+
+    package.changelogFile.writeAsStringSync(newChangelog.toString());
+
+    print('  Removing pending changelog files...');
+    for (final File file in pendingChangelogFiles) {
+      final io.ProcessResult rmResult =
+          await repository.runCommand(<String>['rm', file.path]);
+      if (rmResult.exitCode != 0) {
+        printError('Failed to rm ${file.path}: ${rmResult.stderr}');
+        throw ToolExit(_kGitFailedToPush);
+      }
+    }
+
+    print('  Staging changes...');
+    final io.ProcessResult addResult = await repository.runCommand(
+        <String>['add', package.pubspecFile.path, package.changelogFile.path]);
+    if (addResult.exitCode != 0) {
+      printError('Failed to git add: ${addResult.stderr}');
+      throw ToolExit(_kGitFailedToPush);
+    }
+
+    print('  Committing changes...');
+    final io.ProcessResult commitResult = await repository.runCommand(<String>[
+      'commit',
+      '-m',
+      '${package.displayName}: Prepare for release'
+    ]);
+    if (commitResult.exitCode != 0) {
+      printError('Failed to commit: ${commitResult.stderr}');
+      throw ToolExit(_kGitFailedToPush);
+    }
+
+    print('  Pushing to remote...');
+    final io.ProcessResult pushResult = await repository
+        .runCommand(<String>['push', 'origin', branchName, '--force']);
+    if (pushResult.exitCode != 0) {
+      printError('Failed to push to $branchName: ${pushResult.stderr}');
+      throw ToolExit(_kGitFailedToPush);
+    }
+  }
+}
+
+/// A data class for pending changelogs.
+class PendingChangelogs {
+  /// Creates a new instance.
+  PendingChangelogs(this.entries, this.files);
+
+  /// The parsed pending changelog entries.
+  final List<PendingChangelogEntry> entries;
+
+  /// The files that the pending changelog entries were parsed from.
+  final List<File> files;
+}
+
+/// A data class for processed release information.
+class ReleaseInfo {
+  /// Creates a new instance.
+  ReleaseInfo(this.newVersion, this.changelogs);
+
+  /// The new version for the release, or null if there is no version change.
+  final Version? newVersion;
+
+  /// The combined changelog entries.
+  final List<String> changelogs;
+}
+
+/// The type of version change for a release.
+enum VersionChange {
+  /// A major version change (e.g., 1.2.3 -> 2.0.0).
+  major,
+
+  /// A minor version change (e.g., 1.2.3 -> 1.3.0).
+  minor,
+
+  /// A patch version change (e.g., 1.2.3 -> 1.2.4).
+  patch,
+
+  /// No version change.
+  skip,
+}
+
+/// Represents a single entry in the pending changelog.
+class PendingChangelogEntry {
+  /// Creates a new pending changelog entry.
+  PendingChangelogEntry({required this.changelog, required this.version});
+
+  /// Creates a PendingChangelogEntry from a YAML string.
+  factory PendingChangelogEntry.parse(String yamlContent) {
+    final dynamic yaml = loadYaml(yamlContent);
+    if (yaml is! YamlMap) {
+      throw FormatException(
+          'Expected a YAML map, but found ${yaml.runtimeType}.');
+    }
+
+    final dynamic changelogYaml = yaml['changelog'];
+    if (changelogYaml is! String) {
+      throw FormatException(
+          'Expected "changelog" to be a string, but found ${changelogYaml.runtimeType}.');
+    }
+    final String changelog = changelogYaml.trim();
+
+    final String? versionString = yaml['version'] as String?;
+    if (versionString == null) {
+      throw const FormatException('Missing "version" key.');
+    }
+    final VersionChange version = VersionChange.values.firstWhere(
+      (VersionChange e) => e.name == versionString,
+      orElse: () =>
+          throw FormatException('Invalid version type: $versionString'),
+    );
+
+    return PendingChangelogEntry(changelog: changelog, version: version);
+  }
+
+  /// The changelog messages for this entry.
+  final String changelog;
+
+  /// The type of version change for this entry.
+  final VersionChange version;
+}