flutter update-packages --cherry-pick-package (#128917)

Fixes https://github.com/flutter/flutter/issues/101525

packages/flutter_tools/lib/src/commands/update_packages.dart

@@ -51,6 +51,14 @@ class UpdatePackagesCommand extends FlutterCommand {
               'This will actually modify the pubspec.yaml files in your checkout.',
         negatable: false,
       )
+      ..addOption(
+        'cherry-pick-package',
+        help: 'Attempt to update only the specified package. The "-cherry-pick-version" version must be specified also.',
+      )
+      ..addOption(
+        'cherry-pick-version',
+        help: 'Attempt to update the package to the specified version. The "--cherry-pick-package" option must be specified also.',
+      )
       ..addFlag(
         'paths',
         help: 'Finds paths in the dependency chain leading from package specified '
@@ -182,7 +190,8 @@ class UpdatePackagesCommand extends FlutterCommand {
     final bool isVerifyOnly = boolArg('verify-only');
     final bool isConsumerOnly = boolArg('consumer-only');
     final bool offline = boolArg('offline');
-    final bool doUpgrade = forceUpgrade || isPrintPaths || isPrintTransitiveClosure;
+    final String? cherryPickPackage = stringArg('cherry-pick-package');
+    final String? cherryPickVersion = stringArg('cherry-pick-version');
 
     if (boolArg('crash')) {
       throw StateError('test crash please ignore.');
@@ -194,6 +203,54 @@ class UpdatePackagesCommand extends FlutterCommand {
       );
     }
 
+    if (forceUpgrade && cherryPickPackage != null) {
+      throwToolExit(
+          '--force-upgrade cannot be used with the --cherry-pick-package flag'
+      );
+    }
+
+    if (forceUpgrade && isPrintPaths) {
+      throwToolExit(
+          '--force-upgrade cannot be used with the --paths flag'
+      );
+    }
+
+    if (forceUpgrade && isPrintTransitiveClosure) {
+      throwToolExit(
+          '--force-upgrade cannot be used with the --transitive-closure flag'
+      );
+    }
+
+    if (cherryPickPackage != null && offline) {
+      throwToolExit(
+          '--cherry-pick-package cannot be used with the --offline flag'
+      );
+    }
+
+    if (cherryPickPackage != null && cherryPickVersion == null) {
+      throwToolExit(
+          '--cherry-pick-version is required when using --cherry-pick-package flag'
+      );
+    }
+
+    if (isPrintPaths && (stringArg('from') == null || stringArg('to') == null)) {
+      throwToolExit(
+          'The --from and --to flags are required when using the --paths flag'
+      );
+    }
+
+    if (!isPrintPaths && (stringArg('from') != null || stringArg('to') != null)) {
+      throwToolExit(
+          'The --from and --to flags are only allowed when using the --paths flag'
+      );
+    }
+
+    if (isPrintTransitiveClosure && isPrintPaths) {
+      throwToolExit(
+          'The --transitive-closure flag cannot be used with the --paths flag'
+      );
+    }
+
     // "consumer" packages are those that constitute our public API (e.g. flutter, flutter_test, flutter_driver, flutter_localizations, integration_test).
     if (isConsumerOnly) {
       if (!isPrintTransitiveClosure) {
@@ -216,7 +273,7 @@ class UpdatePackagesCommand extends FlutterCommand {
       return FlutterCommandResult.success();
     }
 
-    if (doUpgrade) {
+    if (forceUpgrade) {
       // This feature attempts to collect all the packages used across all the
       // pubspec.yamls in the repo (including via transitive dependencies), and
       // find the latest version of each that can be used while keeping each
@@ -235,9 +292,38 @@ class UpdatePackagesCommand extends FlutterCommand {
       explicitDependencies: explicitDependencies,
       allDependencies: allDependencies,
       specialDependencies: specialDependencies,
-      doUpgrade: doUpgrade,
+      printPaths: forceUpgrade || isPrintPaths || isPrintTransitiveClosure || cherryPickPackage != null,
     );
 
+    final Iterable<PubspecDependency> baseDependencies;
+    if (cherryPickPackage != null) {
+      if (!allDependencies.containsKey(cherryPickPackage)) {
+        throwToolExit(
+            'Package "$cherryPickPackage" is not currently a dependency, and therefore cannot be upgraded.'
+        );
+      }
+      if (cherryPickVersion != null) {
+        globals.printStatus('Pinning package "$cherryPickPackage" to version "$cherryPickVersion"...');
+      } else {
+        globals.printStatus('Upgrading package "$cherryPickPackage"...');
+      }
+      final List<PubspecDependency> adjustedDependencies = <PubspecDependency>[];
+      for (final String package in allDependencies.keys) {
+        if (package == cherryPickPackage) {
+          assert(cherryPickVersion != null);
+          final PubspecDependency pubspec = allDependencies[cherryPickPackage]!;
+          adjustedDependencies.add(pubspec.copyWith(version: cherryPickVersion));
+        } else {
+          adjustedDependencies.add(allDependencies[package]!);
+        }
+      }
+      baseDependencies = adjustedDependencies;
+    } else if (forceUpgrade) {
+      baseDependencies = explicitDependencies.values;
+    } else {
+      baseDependencies = allDependencies.values;
+    }
+
     // Now that we have all the dependencies we care about, we are going to
     // create a fake package and then run either "pub upgrade", if requested,
     // followed by "pub get" on it. If upgrading, the pub tool will attempt to
@@ -246,12 +332,14 @@ class UpdatePackagesCommand extends FlutterCommand {
     // attempt to download any necessary package versions to the pub cache to
     // warm the cache.
     final PubDependencyTree tree = PubDependencyTree(); // object to collect results
-    await _generateFakePackage(
+    await _pubGetAllDependencies(
       tempDir: _syntheticPackageDir,
-      dependencies: doUpgrade ? explicitDependencies.values : allDependencies.values,
+      dependencies: baseDependencies,
       pubspecs: pubspecs,
       tree: tree,
-      doUpgrade: doUpgrade,
+      doUpgrade: forceUpgrade,
+      isolateEnvironment: forceUpgrade || isPrintPaths || isPrintTransitiveClosure || cherryPickPackage != null,
+      reportDependenciesToTree: forceUpgrade || isPrintPaths || isPrintTransitiveClosure || cherryPickPackage != null,
     );
 
     // Only delete the synthetic package if it was done in a temp directory
@@ -259,18 +347,31 @@ class UpdatePackagesCommand extends FlutterCommand {
       _syntheticPackageDir.deleteSync(recursive: true);
     }
 
-    if (doUpgrade) {
-      final bool done = _upgradePubspecs(
+    if (forceUpgrade || isPrintTransitiveClosure || isPrintPaths || cherryPickPackage != null) {
+      _processPubspecs(
         tree: tree,
         pubspecs: pubspecs,
-        explicitDependencies: explicitDependencies,
         specialDependencies: specialDependencies,
       );
 
-      if (done) {
-        // Complete early if we were just printing data.
+      if (isPrintTransitiveClosure) {
+        tree._dependencyTree.forEach((String from, Set<String> to) {
+          globals.printStatus('$from -> $to');
+        });
         return FlutterCommandResult.success();
       }
+
+      if (isPrintPaths) {
+        showDependencyPaths(from: stringArg('from')!, to: stringArg('to')!, tree: tree);
+        return FlutterCommandResult.success();
+      }
+
+      globals.printStatus('Updating workspace...');
+      _updatePubspecs(
+        tree: tree,
+        pubspecs: pubspecs,
+        specialDependencies: specialDependencies,
+      );
     }
 
     await _runPubGetOnPackages(packages);
@@ -306,8 +407,9 @@ class UpdatePackagesCommand extends FlutterCommand {
         // we need to run update-packages to recapture the transitive deps.
         globals.printWarning(
             'Warning: pubspec in ${directory.path} has updated or new dependencies. '
-            'Please run "flutter update-packages --force-upgrade" to update them correctly '
-            '(checksum ${pubspec.checksum.value} != $checksum).'
+            'Please run "flutter update-packages --force-upgrade" to update them correctly.'
+            // DO NOT PRINT THE CHECKSUM HERE.
+            // It causes people to ignore the requirement to actually run the script.
         );
         needsUpdate = true;
       } else {
@@ -331,11 +433,11 @@ class UpdatePackagesCommand extends FlutterCommand {
     required Set<String> specialDependencies,
     required Map<String, PubspecDependency> explicitDependencies,
     required Map<String, PubspecDependency> allDependencies,
-    required bool doUpgrade,
+    required bool printPaths,
   }) {
     // Visit all the directories with pubspec.yamls we care about.
     for (final Directory directory in packages) {
-      if (doUpgrade) {
+      if (printPaths) {
         globals.printTrace('Reading pubspec.yaml from: ${directory.path}');
       }
       final PubspecYaml pubspec = PubspecYaml(directory); // this parses the pubspec.yaml
@@ -404,12 +506,14 @@ class UpdatePackagesCommand extends FlutterCommand {
     }
   }
 
-  Future<void> _generateFakePackage({
+  Future<void> _pubGetAllDependencies({
     required Directory tempDir,
     required Iterable<PubspecDependency> dependencies,
     required List<PubspecYaml> pubspecs,
     required PubDependencyTree tree,
     required bool doUpgrade,
+    required bool isolateEnvironment,
+    required bool reportDependenciesToTree,
   }) async {
     Directory? temporaryFlutterSdk;
     final Directory syntheticPackageDir = tempDir.childDirectory('synthetic_package');
@@ -421,9 +525,10 @@ class UpdatePackagesCommand extends FlutterCommand {
         doUpgrade: doUpgrade,
       ),
     );
+
+    if (isolateEnvironment) {
       // Create a synthetic flutter SDK so that transitive flutter SDK
       // constraints are not affected by this upgrade.
-    if (doUpgrade) {
       temporaryFlutterSdk = createTemporaryFlutterSdk(
         globals.logger,
         globals.fs,
@@ -433,8 +538,10 @@ class UpdatePackagesCommand extends FlutterCommand {
       );
     }
 
-    // Next we run "pub get" on it in order to force the download of any
+    // Run "pub get" on it in order to force the download of any
     // needed packages to the pub cache, upgrading if requested.
+    // TODO(ianh): If this fails, the tool exits silently.
+    // It can fail, e.g., if --cherry-pick-version is invalid.
     await pub.get(
       context: PubContext.updatePackages,
       project: FlutterProject.fromDirectory(syntheticPackageDir),
@@ -444,9 +551,9 @@ class UpdatePackagesCommand extends FlutterCommand {
       outputMode: PubOutputMode.none,
     );
 
-    if (doUpgrade) {
-      // If upgrading, we run "pub deps --style=compact" on the result. We
-      // pipe all the output to tree.fill(), which parses it so that it can
+    if (reportDependenciesToTree) {
+      // Run "pub deps --style=compact" on the result.
+      // We pipe all the output to tree.fill(), which parses it so that it can
       // create a graph of all the dependencies so that we can figure out the
       // transitive dependencies later. It also remembers which version was
       // selected for each package.
@@ -459,40 +566,29 @@ class UpdatePackagesCommand extends FlutterCommand {
     }
   }
 
-  bool _upgradePubspecs({
+  void _processPubspecs({
     required PubDependencyTree tree,
     required List<PubspecYaml> pubspecs,
     required Set<String> specialDependencies,
-    required Map<String, PubspecDependency> explicitDependencies,
   }) {
-    // The transitive dependency tree for the fake package does not contain
-    // dependencies between Flutter SDK packages and pub packages. We add them
-    // here.
     for (final PubspecYaml pubspec in pubspecs) {
       final String package = pubspec.name;
       specialDependencies.add(package);
       tree._versions[package] = pubspec.version;
-      assert(!tree._dependencyTree.containsKey(package));
-      tree._dependencyTree[package] = <String>{};
       for (final PubspecDependency dependency in pubspec.dependencies) {
         if (dependency.kind == DependencyKind.normal) {
+          tree._dependencyTree[package] ??= <String>{};
           tree._dependencyTree[package]!.add(dependency.name);
         }
       }
     }
-
-    if (boolArg('transitive-closure')) {
-      tree._dependencyTree.forEach((String from, Set<String> to) {
-        globals.printStatus('$from -> $to');
-      });
-      return true;
-    }
-
-    if (boolArg('paths')) {
-      showDependencyPaths(from: stringArg('from')!, to: stringArg('to')!, tree: tree);
-      return true;
   }
 
+  bool _updatePubspecs({
+    required PubDependencyTree tree,
+    required List<PubspecYaml> pubspecs,
+    required Set<String> specialDependencies,
+  }) {
     // Now that we have collected all the data, we can apply our dependency
     // versions to each pubspec.yaml that we collected. This mutates the
     // pubspec.yaml files.
@@ -662,7 +758,6 @@ enum DependencyKind {
 /// pubspec.yaml file.
 const String kTransitiveMagicString= '# THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"';
 
-
 /// This is the string output before a checksum of the packages used.
 const String kDependencyChecksum = '# PUBSPEC CHECKSUM: ';
 
@@ -1288,6 +1383,28 @@ class PubspecDependency extends PubspecLine {
   static const String _sdkPrefix = '    sdk: ';
   static const String _gitPrefix = '    git:';
 
+  PubspecDependency copyWith({
+    String? line,
+    String? name,
+    String? suffix,
+    bool? isTransitive,
+    DependencyKind? kind,
+    String? version,
+    String? sourcePath,
+    bool? isDevDependency,
+  }) {
+    return PubspecDependency(
+      line ?? this.line,
+      name ?? this.name,
+      suffix ?? this.suffix,
+      isTransitive: isTransitive ?? this.isTransitive,
+      kind: kind ?? this.kind,
+      version: version ?? this.version,
+      sourcePath: sourcePath ?? this.sourcePath,
+      isDevDependency: isDevDependency ?? this.isDevDependency,
+    );
+  }
+
   /// Whether the dependency points to a package in the Flutter SDK.
   ///
   /// There are two ways one can point to a Flutter package:
@@ -1353,16 +1470,16 @@ class PubspecDependency extends PubspecLine {
   /// This generates the entry for this dependency for the pubspec.yaml for the
   /// fake package that we'll use to get the version numbers figured out.
   ///
-  /// When called with [doUpgrade] as [true], the version constrains will be set
-  /// to >= whatever the previous version was. If [doUpgrade] is [false], then
+  /// When called with [allowUpgrade] as [true], the version constrains will be set
+  /// to >= whatever the previous version was. If [allowUpgrade] is [false], then
   /// the previous version is used again as an exact pin.
-  void describeForFakePubspec(StringBuffer dependencies, StringBuffer overrides, { bool doUpgrade = true }) {
+  void describeForFakePubspec(StringBuffer dependencies, StringBuffer overrides, { bool allowUpgrade = true }) {
     final String versionToUse;
     // This should only happen when manually adding new dependencies; otherwise
     // versions should always be pinned exactly
     if (version.isEmpty || version == 'any') {
       versionToUse = 'any';
-    } else if (doUpgrade) {
+    } else if (allowUpgrade) {
       // Must wrap in quotes for Yaml parsing
       versionToUse = "'>= $version'";
     } else {
@@ -1445,7 +1562,7 @@ String generateFakePubspec(
       // Don't add pinned dependency if it is not in the set of all transitive dependencies.
       if (!allTransitive.contains(package)) {
         if (verbose) {
-          globals.printStatus('Skipping $package because it was not transitive');
+          globals.printStatus('  - $package: $version (skipped because it was not a transitive dependency)');
         }
         return;
       }
@@ -1457,7 +1574,7 @@ String generateFakePubspec(
   }
   for (final PubspecDependency dependency in dependencies) {
     if (!dependency.pointsToSdk) {
-      dependency.describeForFakePubspec(result, overrides, doUpgrade: doUpgrade);
+      dependency.describeForFakePubspec(result, overrides, allowUpgrade: doUpgrade);
     }
   }
   result.write(overrides.toString());

packages/flutter_tools/test/commands.shard/hermetic/update_packages_test.dart

@@ -197,6 +197,73 @@ void main() {
       Logger: () => logger,
     });
 
+    testUsingContext('--cherry-pick-package', () async {
+      final UpdatePackagesCommand command = UpdatePackagesCommand();
+      await createTestCommandRunner(command).run(<String>[
+        'update-packages',
+        '--cherry-pick-package=vector_math',
+        '--cherry-pick-version=2.0.9',
+      ]);
+      expect(pub.pubGetDirectories, equals(<String>[
+        '/.tmp_rand0/flutter_update_packages.rand0/synthetic_package',
+        '/flutter/examples',
+        '/flutter/packages/flutter',
+      ]));
+      expect(pub.pubBatchDirectories, equals(<String>[
+        '/.tmp_rand0/flutter_update_packages.rand0/synthetic_package',
+      ]));
+      expect(pub.pubspecYamls, hasLength(3));
+      final String output = pub.pubspecYamls.first;
+      expect(output, isNotNull);
+      expect(output, contains('collection: 1.14.11\n'));
+      expect(output, contains('meta: 1.1.8\n'));
+      expect(output, contains('typed_data: 1.1.6\n'));
+      expect(output, contains('vector_math: 2.0.9\n'));
+      expect(output, isNot(contains('vector_math: 2.0.8')));
+      expect(output, isNot(contains('vector_math: ">= 2.0.8"')));
+      expect(output, isNot(contains("vector_math: '>= 2.0.8'")));
+    }, overrides: <Type, Generator>{
+      Pub: () => pub,
+      FileSystem: () => fileSystem,
+      ProcessManager: () => processManager,
+      Cache: () => Cache.test(
+        processManager: processManager,
+      ),
+      Logger: () => logger,
+    });
+
+    testUsingContext('--force-upgrade', () async {
+      final UpdatePackagesCommand command = UpdatePackagesCommand();
+      await createTestCommandRunner(command).run(<String>[
+        'update-packages',
+        '--force-upgrade',
+      ]);
+      expect(pub.pubGetDirectories, equals(<String>[
+        '/.tmp_rand0/flutter_update_packages.rand0/synthetic_package',
+        '/flutter/examples',
+        '/flutter/packages/flutter',
+      ]));
+      expect(pub.pubBatchDirectories, equals(<String>[
+        '/.tmp_rand0/flutter_update_packages.rand0/synthetic_package',
+      ]));
+      expect(pub.pubspecYamls, hasLength(3));
+      final String output = pub.pubspecYamls.first;
+      expect(output, isNotNull);
+      expect(output, contains("collection: '>= 1.14.11'\n"));
+      expect(output, contains("meta: '>= 1.1.8'\n"));
+      expect(output, contains("typed_data: '>= 1.1.6'\n"));
+      expect(output, contains("vector_math: '>= 2.0.8'\n"));
+      expect(output, isNot(contains('vector_math: 2.0.8')));
+    }, overrides: <Type, Generator>{
+      Pub: () => pub,
+      FileSystem: () => fileSystem,
+      ProcessManager: () => processManager,
+      Cache: () => Cache.test(
+        processManager: processManager,
+      ),
+      Logger: () => logger,
+    });
+
     testUsingContext('force updates packages --synthetic-package-path', () async {
       final UpdatePackagesCommand command = UpdatePackagesCommand();
       const String dir = '/path/to/synthetic/package';
@@ -272,6 +339,7 @@ class FakePub extends Fake implements Pub {
   final FileSystem fileSystem;
   final List<String> pubGetDirectories = <String>[];
   final List<String> pubBatchDirectories = <String>[];
+  final List<String> pubspecYamls = <String>[];
 
   @override
   Future<void> get({
@@ -287,6 +355,7 @@ class FakePub extends Fake implements Pub {
     PubOutputMode outputMode = PubOutputMode.all,
   }) async {
     pubGetDirectories.add(project.directory.path);
+    pubspecYamls.add(project.directory.childFile('pubspec.yaml').readAsStringSync());
     project.directory.childFile('pubspec.lock')
       ..createSync(recursive: true)
       ..writeAsStringSync('''