[tool] Move changed file detection to base command class

Consolidates the code to find all changed file paths into the
`PackageLoopingCommand` class that is the base of almost all of the repo
tooling commands. This in a preparatory PR for a future change to allow
each command to define a list of files or file patterns that
definitively *don't* affect that test, so that CI can be smarter about
what tests to run (e.g., not running expensive integration tests for
README changes).

A side effect of this change is that tests of almost all commands now
need a mock `GitDir` instance. This would add a lot of copy/pasted
boilerplate to the test setup, and there is already too much of that, so
instead this refactors common test setup:
- Creating a memory file system
- Populating it with a packages directory
- Creating a RecordingProcessRunner to mock out process calls
- Creating a mock GitDir that forwards to a RecordingProcessRunner

into a helper method (using records and destructuring to easily return
multiple values). While some tests don't need all of these steps, those
that don't can easily ignore parts of it, and it will make it much
easier to update tests in the future if they need them, and it makes the
setup much more consistent which makes it easier to reason about test
setup in general.

Prep for flutter/flutter#136394

script/tool/lib/src/analyze_command.dart

@@ -17,6 +17,7 @@ class AnalyzeCommand extends PackageLoopingCommand {
     super.packagesDir, {
     super.processRunner,
     super.platform,
+    super.gitDir,
   }) {
     argParser.addMultiOption(_customAnalysisFlag,
         help:

script/tool/lib/src/build_examples_command.dart

@@ -48,6 +48,7 @@ class BuildExamplesCommand extends PackageLoopingCommand {
     super.packagesDir, {
     super.processRunner,
     super.platform,
+    super.gitDir,
   }) {
     argParser.addFlag(platformLinux);
     argParser.addFlag(platformMacOS);

script/tool/lib/src/common/git_version_finder.dart

@@ -28,15 +28,6 @@ class GitVersionFinder {
   /// The base branche used to find a merge point if baseSha is not provided.
   final String _baseBranch;
 
-  static bool _isPubspec(String file) {
-    return file.trim().endsWith('pubspec.yaml');
-  }
-
-  /// Get a list of all the pubspec.yaml file that is changed.
-  Future<List<String>> getChangedPubSpecs() async {
-    return (await getChangedFiles()).where(_isPubspec).toList();
-  }
-
   /// Get a list of all the changed files.
   Future<List<String>> getChangedFiles(
       {bool includeUncommitted = false}) async {

script/tool/lib/src/common/package_looping_command.dart

@@ -9,6 +9,7 @@ import 'package:path/path.dart' as p;
 import 'package:pub_semver/pub_semver.dart';
 
 import 'core.dart';
+import 'git_version_finder.dart';
 import 'output_utils.dart';
 import 'package_command.dart';
 import 'repository_package.dart';
@@ -226,6 +227,17 @@ abstract class PackageLoopingCommand extends PackageCommand {
   /// The suggested indentation for printed output.
   String get indentation => hasLongOutput ? '' : '  ';
 
+  /// The base SHA used to calculate changed files.
+  ///
+  /// This is guaranteed to be populated before [initializeRun] is called.
+  late String baseSha;
+
+  /// The repo-relative paths (using Posix separators) of all files changed
+  /// relative to [baseSha].
+  ///
+  /// This is guaranteed to be populated before [initializeRun] is called.
+  late List<String> changedFiles;
+
   // ----------------------------------------
 
   @override
@@ -264,6 +276,11 @@ abstract class PackageLoopingCommand extends PackageCommand {
 
     final DateTime runStart = DateTime.now();
 
+    // Populate the list of changed files for subclasses to use.
+    final GitVersionFinder gitVersionFinder = await retrieveVersionFinder();
+    baseSha = await gitVersionFinder.getBaseSha();
+    changedFiles = await gitVersionFinder.getChangedFiles();
+
     await initializeRun();
 
     final List<PackageEnumerationEntry> targetPackages =

script/tool/lib/src/custom_test_command.dart

@@ -21,6 +21,7 @@ class CustomTestCommand extends PackageLoopingCommand {
     super.packagesDir, {
     super.processRunner,
     super.platform,
+    super.gitDir,
   });
 
   @override

script/tool/lib/src/dart_test_command.dart

@@ -27,6 +27,7 @@ class DartTestCommand extends PackageLoopingCommand {
     super.packagesDir, {
     super.processRunner,
     super.platform,
+    super.gitDir,
   }) {
     argParser.addOption(
       kEnableExperiment,

script/tool/lib/src/drive_examples_command.dart

@@ -27,6 +27,7 @@ class DriveExamplesCommand extends PackageLoopingCommand {
     super.packagesDir, {
     super.processRunner,
     super.platform,
+    super.gitDir,
   }) {
     argParser.addFlag(platformAndroid,
         help: 'Runs the Android implementation of the examples',

script/tool/lib/src/federation_safety_check_command.dart

@@ -59,9 +59,8 @@ class FederationSafetyCheckCommand extends PackageLoopingCommand {
   @override
   Future<void> initializeRun() async {
     final GitVersionFinder gitVersionFinder = await retrieveVersionFinder();
-    final String baseSha = await gitVersionFinder.getBaseSha();
     print('Validating changes relative to "$baseSha"\n');
-    for (final String path in await gitVersionFinder.getChangedFiles()) {
+    for (final String path in changedFiles) {
       // Git output always uses Posix paths.
       final List<String> allComponents = p.posix.split(path);
       final int packageIndex = allComponents.indexOf('packages');

script/tool/lib/src/fetch_deps_command.dart

@@ -27,6 +27,7 @@ class FetchDepsCommand extends PackageLoopingCommand {
     super.packagesDir, {
     super.processRunner,
     super.platform,
+    super.gitDir,
   }) {
     argParser.addFlag(_dartFlag, defaultsTo: true, help: 'Run "pub get"');
     argParser.addFlag(_supportingTargetPlatformsOnlyFlag,

script/tool/lib/src/firebase_test_lab_command.dart

@@ -23,6 +23,7 @@ class FirebaseTestLabCommand extends PackageLoopingCommand {
     super.packagesDir, {
     super.processRunner,
     super.platform,
+    super.gitDir,
   }) {
     argParser.addOption(
       _gCloudProjectArg,

script/tool/lib/src/fix_command.dart

@@ -13,6 +13,7 @@ class FixCommand extends PackageLoopingCommand {
     super.packagesDir, {
     super.processRunner,
     super.platform,
+    super.gitDir,
   });
 
   @override

script/tool/lib/src/format_command.dart

@@ -49,6 +49,7 @@ class FormatCommand extends PackageLoopingCommand {
     super.packagesDir, {
     super.processRunner,
     super.platform,
+    super.gitDir,
   }) {
     argParser.addFlag(_failonChangeArg, hide: true);
     argParser.addFlag(_dartArg, help: 'Format Dart files', defaultsTo: true);

script/tool/lib/src/gradle_check_command.dart

@@ -19,7 +19,10 @@ final Version minKotlinVersion = Version(1, 7, 10);
 /// A command to enforce gradle file conventions and best practices.
 class GradleCheckCommand extends PackageLoopingCommand {
   /// Creates an instance of the gradle check command.
-  GradleCheckCommand(super.packagesDir);
+  GradleCheckCommand(
+    super.packagesDir, {
+    super.gitDir,
+  });
 
   @override
   final String name = 'gradle-check';

script/tool/lib/src/lint_android_command.dart

@@ -18,6 +18,7 @@ class LintAndroidCommand extends PackageLoopingCommand {
     super.packagesDir, {
     super.processRunner,
     super.platform,
+    super.gitDir,
   });
 
   @override

script/tool/lib/src/native_test_command.dart

@@ -45,6 +45,7 @@ class NativeTestCommand extends PackageLoopingCommand {
     super.packagesDir, {
     super.processRunner,
     super.platform,
+    super.gitDir,
     Abi? abi,
   })  : _abi = abi ?? Abi.current(),
         _xcode = Xcode(processRunner: processRunner, log: true) {

script/tool/lib/src/podspec_check_command.dart

@@ -25,6 +25,7 @@ class PodspecCheckCommand extends PackageLoopingCommand {
     super.packagesDir, {
     super.processRunner,
     super.platform,
+    super.gitDir,
   });
 
   @override

script/tool/lib/src/publish_check_command.dart

@@ -23,6 +23,7 @@ class PublishCheckCommand extends PackageLoopingCommand {
     super.packagesDir, {
     super.processRunner,
     super.platform,
+    super.gitDir,
     http.Client? httpClient,
   }) : _pubVersionFinder =
             PubVersionFinder(httpClient: httpClient ?? http.Client()) {

script/tool/lib/src/publish_command.dart

@@ -17,7 +17,6 @@ import 'package:yaml/yaml.dart';
 
 import 'common/core.dart';
 import 'common/file_utils.dart';
-import 'common/git_version_finder.dart';
 import 'common/output_utils.dart';
 import 'common/package_command.dart';
 import 'common/package_looping_command.dart';
@@ -175,12 +174,12 @@ class PublishCommand extends PackageLoopingCommand {
   @override
   Stream<PackageEnumerationEntry> getPackagesToProcess() async* {
     if (getBoolArg(_allChangedFlag)) {
-      final GitVersionFinder gitVersionFinder = await retrieveVersionFinder();
-      final String baseSha = await gitVersionFinder.getBaseSha();
       print(
           'Publishing all packages that have changed relative to "$baseSha"\n');
-      final List<String> changedPubspecs =
-          await gitVersionFinder.getChangedPubSpecs();
+
+      final List<String> changedPubspecs = changedFiles
+          .where((String file) => file.trim().endsWith('pubspec.yaml'))
+          .toList();
 
       for (final String pubspecPath in changedPubspecs) {
         // git outputs a relativa, Posix-style path.

script/tool/lib/src/remove_dev_dependencies_command.dart

@@ -15,7 +15,10 @@ import 'common/repository_package.dart';
 /// clients of the library, but not for development of the library.
 class RemoveDevDependenciesCommand extends PackageLoopingCommand {
   /// Creates a publish metadata updater command instance.
-  RemoveDevDependenciesCommand(super.packagesDir);
+  RemoveDevDependenciesCommand(
+    super.packagesDir, {
+    super.gitDir,
+  });
 
   @override
   final String name = 'remove-dev-dependencies';

script/tool/lib/src/update_dependency_command.dart

@@ -32,6 +32,7 @@ class UpdateDependencyCommand extends PackageLoopingCommand {
   UpdateDependencyCommand(
     super.packagesDir, {
     super.processRunner,
+    super.gitDir,
     http.Client? httpClient,
   }) : _pubVersionFinder =
             PubVersionFinder(httpClient: httpClient ?? http.Client()) {

script/tool/lib/src/update_min_sdk_command.dart

@@ -15,7 +15,10 @@ const int _exitUnknownVersion = 3;
 /// A command to update the minimum Flutter and Dart SDKs of packages.
 class UpdateMinSdkCommand extends PackageLoopingCommand {
   /// Creates a publish metadata updater command instance.
-  UpdateMinSdkCommand(super.packagesDir) {
+  UpdateMinSdkCommand(
+    super.packagesDir, {
+    super.gitDir,
+  }) {
     argParser.addOption(_flutterMinFlag,
         mandatory: true,
         help: 'The minimum version of Flutter to set SDK constraints to.');

script/tool/lib/src/update_release_info_command.dart

@@ -7,7 +7,6 @@ import 'package:file/file.dart';
 import 'package:pub_semver/pub_semver.dart';
 import 'package:yaml_edit/yaml_edit.dart';
 
-import 'common/git_version_finder.dart';
 import 'common/output_utils.dart';
 import 'common/package_looping_command.dart';
 import 'common/package_state_utils.dart';
@@ -76,11 +75,6 @@ class UpdateReleaseInfoCommand extends PackageLoopingCommand {
   // If null, either there is no version change, or it is dynamic (`minimal`).
   _VersionIncrementType? _versionChange;
 
-  // The cache of changed files, for dynamic version change determination.
-  //
-  // Only set for `minimal` version change.
-  late final List<String> _changedFiles;
-
   @override
   final String name = 'update-release-info';
 
@@ -103,12 +97,6 @@ class UpdateReleaseInfoCommand extends PackageLoopingCommand {
       case _versionBugfix:
         _versionChange = _VersionIncrementType.bugfix;
       case _versionMinimal:
-        final GitVersionFinder gitVersionFinder = await retrieveVersionFinder();
-        // If the line below fails with "Not a valid object name FETCH_HEAD"
-        // run "git fetch", FETCH_HEAD is a temporary reference that only exists
-        // after a fetch. This can happen when a branch is made locally and
-        // pushed but never fetched.
-        _changedFiles = await gitVersionFinder.getChangedFiles();
         // Anothing other than a fixed change is null.
         _versionChange = null;
       case _versionNext:
@@ -133,8 +121,7 @@ class UpdateReleaseInfoCommand extends PackageLoopingCommand {
       final String relativePackagePath =
           getRelativePosixPath(package.directory, from: gitRoot);
       final PackageChangeState state = await checkPackageChangeState(package,
-          changedPaths: _changedFiles,
-          relativePackagePath: relativePackagePath);
+          changedPaths: changedFiles, relativePackagePath: relativePackagePath);
 
       if (!state.hasChanges) {
         return PackageResult.skip('No changes to package');

script/tool/lib/src/version_check_command.dart

@@ -154,8 +154,6 @@ class VersionCheckCommand extends PackageLoopingCommand {
   final PubVersionFinder _pubVersionFinder;
 
   late final GitVersionFinder _gitVersionFinder;
-  late final String _mergeBase;
-  late final List<String> _changedFiles;
 
   late final Set<String> _prLabels = _getPRLabels();
 
@@ -177,8 +175,6 @@ class VersionCheckCommand extends PackageLoopingCommand {
   @override
   Future<void> initializeRun() async {
     _gitVersionFinder = await retrieveVersionFinder();
-    _mergeBase = await _gitVersionFinder.getBaseSha();
-    _changedFiles = await _gitVersionFinder.getChangedFiles();
   }
 
   @override
@@ -279,7 +275,7 @@ ${indentation}HTTP response: ${pubVersionFinderResponse.httpResponse.body}
     final String gitPath = path.style == p.Style.windows
         ? p.posix.joinAll(path.split(relativePath))
         : relativePath;
-    return _gitVersionFinder.getPackageVersion(gitPath, gitRef: _mergeBase);
+    return _gitVersionFinder.getPackageVersion(gitPath, gitRef: baseSha);
   }
 
   /// Returns the state of the verison of [package] relative to the comparison
@@ -303,7 +299,7 @@ ${indentation}HTTP response: ${pubVersionFinderResponse.httpResponse.body}
             '$indentation${pubspec.name}: Current largest version on pub: $previousVersion');
       }
     } else {
-      previousVersionSource = _mergeBase;
+      previousVersionSource = baseSha;
       previousVersion =
           await _getPreviousVersionFromGit(package) ?? Version.none;
     }
@@ -535,15 +531,15 @@ ${indentation}The first version listed in CHANGELOG.md is $fromChangeLog.
   /// This should only be called if the version did not change.
   Future<String?> _checkForMissingChangeError(RepositoryPackage package) async {
     // Find the relative path to the current package, as it would appear at the
-    // beginning of a path reported by getChangedFiles() (which always uses
+    // beginning of a path reported by changedFiles (which always uses
     // Posix paths).
     final Directory gitRoot =
         packagesDir.fileSystem.directory((await gitDir).path);
     final String relativePackagePath =
         getRelativePosixPath(package.directory, from: gitRoot);
 
     final PackageChangeState state = await checkPackageChangeState(package,
-        changedPaths: _changedFiles,
+        changedPaths: changedFiles,
         relativePackagePath: relativePackagePath,
         git: await retrieveVersionFinder());
 

script/tool/lib/src/xcode_analyze_command.dart

@@ -16,6 +16,7 @@ class XcodeAnalyzeCommand extends PackageLoopingCommand {
     super.packagesDir, {
     super.processRunner,
     super.platform,
+    super.gitDir,
   }) : _xcode = Xcode(processRunner: processRunner, log: true) {
     argParser.addFlag(platformIOS, help: 'Analyze iOS');
     argParser.addFlag(platformMacOS, help: 'Analyze macOS');

script/tool/test/analyze_command_test.dart

@@ -4,29 +4,29 @@
 
 import 'package:args/command_runner.dart';
 import 'package:file/file.dart';
-import 'package:file/memory.dart';
 import 'package:flutter_plugin_tools/src/analyze_command.dart';
 import 'package:flutter_plugin_tools/src/common/core.dart';
+import 'package:git/git.dart';
 import 'package:test/test.dart';
 
 import 'mocks.dart';
 import 'util.dart';
 
 void main() {
-  late FileSystem fileSystem;
   late MockPlatform mockPlatform;
   late Directory packagesDir;
   late RecordingProcessRunner processRunner;
   late CommandRunner<void> runner;
 
   setUp(() {
-    fileSystem = MemoryFileSystem();
     mockPlatform = MockPlatform();
-    packagesDir = createPackagesDirectory(fileSystem: fileSystem);
-    processRunner = RecordingProcessRunner();
+    final GitDir gitDir;
+    (:packagesDir, :processRunner, gitProcessRunner: _, :gitDir) =
+        configureBaseCommandMocks(platform: mockPlatform);
     final AnalyzeCommand analyzeCommand = AnalyzeCommand(
       packagesDir,
       processRunner: processRunner,
+      gitDir: gitDir,
       platform: mockPlatform,
     );