[flutter_plugin_tools] Restructure version-check

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

@@ -58,6 +58,16 @@ void printSuccess(String successMessage) {
   print(Colorize(successMessage)..green());
 }
 
+/// Prints `warningMessage` in yellow.
+///
+/// Warnings are not surfaced in CI summaries, so this is only useful for
+/// highlighting something when someone is already looking though the log
+/// messages. DO NOT RELY on someone noticing a warning; instead, use it for
+/// things that might be useful to someone debugging an unexpected result.
+void printWarning(String warningMessage) {
+  print(Colorize(warningMessage)..yellow());
+}
+
 /// Prints `errorMessage` in red.
 void printError(String errorMessage) {
   print(Colorize(errorMessage)..red());

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

@@ -35,6 +35,10 @@ abstract class PackageLoopingCommand extends PluginCommand {
   /// in the final summary. An empty list indicates success.
   Future<List<String>> runForPackage(Directory package);
 
+  /// Called during [run] after all calls to [runForPackage]. This provides an
+  /// opportunity to do any cleanup of run-level state.
+  Future<void> completeRun() async {}
+
   /// Whether or not the output (if any) of [runForPackage] is long, or short.
   ///
   /// This changes the logging that happens at the start of each package's
@@ -99,6 +103,9 @@ abstract class PackageLoopingCommand extends PluginCommand {
     return packageName;
   }
 
+  /// The suggested indentation for printed output.
+  String get indentation => hasLongOutput ? '' : '  ';
+
   // ----------------------------------------
 
   @override
@@ -115,6 +122,8 @@ abstract class PackageLoopingCommand extends PluginCommand {
       results[package] = await runForPackage(package);
     }
 
+    completeRun();
+
     // If there were any errors reported, summarize them and exit.
     if (results.values.any((List<String> failures) => failures.isNotEmpty)) {
       const String indentation = '  ';

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

@@ -20,8 +20,8 @@ abstract class PluginCommand extends Command<void> {
   PluginCommand(
     this.packagesDir, {
     this.processRunner = const ProcessRunner(),
-    this.gitDir,
-  }) {
+    GitDir? gitDir,
+  }) : _gitDir = gitDir {
     argParser.addMultiOption(
       _pluginsArg,
       splitCommas: true,
@@ -76,10 +76,11 @@ abstract class PluginCommand extends Command<void> {
   /// This can be overridden for testing.
   final ProcessRunner processRunner;
 
-  /// The git directory to use. By default it uses the parent directory.
+  /// The git directory to use. If unset, [gitDir] populates it from the
+  /// packages directory's enclosing repository.
   ///
   /// This can be mocked for testing.
-  final GitDir? gitDir;
+  GitDir? _gitDir;
 
   int? _shardIndex;
   int? _shardCount;
@@ -100,6 +101,26 @@ abstract class PluginCommand extends Command<void> {
     return _shardCount!;
   }
 
+  /// Returns the [GitDir] containing [packagesDir].
+  Future<GitDir> get gitDir async {
+    GitDir? gitDir = _gitDir;
+    if (gitDir != null) {
+      return gitDir;
+    }
+
+    // Ensure there are no symlinks in the path, as it can break
+    // GitDir's allowSubdirectory:true.
+    final String packagesPath = packagesDir.resolveSymbolicLinksSync();
+    if (!await GitDir.isGitDir(packagesPath)) {
+      printError('$packagesPath is not a valid Git repository.');
+      throw ToolExit(2);
+    }
+    gitDir =
+        await GitDir.fromExisting(packagesDir.path, allowSubdirectory: true);
+    _gitDir = gitDir;
+    return gitDir;
+  }
+
   /// Convenience accessor for boolean arguments.
   bool getBoolArg(String key) {
     return (argResults![key] as bool?) ?? false;
@@ -285,22 +306,10 @@ abstract class PluginCommand extends Command<void> {
   ///
   /// Throws tool exit if [gitDir] nor root directory is a git directory.
   Future<GitVersionFinder> retrieveVersionFinder() async {
-    final String rootDir = packagesDir.parent.absolute.path;
     final String baseSha = getStringArg(_kBaseSha);
 
-    GitDir? baseGitDir = gitDir;
-    if (baseGitDir == null) {
-      if (!await GitDir.isGitDir(rootDir)) {
-        printError(
-          '$rootDir is not a valid Git repository.',
-        );
-        throw ToolExit(2);
-      }
-      baseGitDir = await GitDir.fromExisting(rootDir);
-    }
-
     final GitVersionFinder gitVersionFinder =
-        GitVersionFinder(baseGitDir, baseSha);
+        GitVersionFinder(await gitDir, baseSha);
     return gitVersionFinder;
   }
 

script/tool/lib/src/publish_plugin_command.dart

@@ -149,15 +149,7 @@ class PublishPluginCommand extends PluginCommand {
     }
 
     _print('Checking local repo...');
-    // Ensure there are no symlinks in the path, as it can break
-    // GitDir's allowSubdirectory:true.
-    final String packagesPath = packagesDir.resolveSymbolicLinksSync();
-    if (!await GitDir.isGitDir(packagesPath)) {
-      _print('$packagesPath is not a valid Git repository.');
-      throw ToolExit(1);
-    }
-    final GitDir baseGitDir = gitDir ??
-        await GitDir.fromExisting(packagesPath, allowSubdirectory: true);
+    final GitDir repository = await gitDir;
 
     final bool shouldPushTag = getBoolArg(_pushTagsOption);
     _RemoteInfo? remote;
@@ -179,7 +171,7 @@ class PublishPluginCommand extends PluginCommand {
     bool successful;
     if (publishAllChanged) {
       successful = await _publishAllChangedPackages(
-        baseGitDir: baseGitDir,
+        baseGitDir: repository,
         remoteForTagPush: remote,
       );
     } else {

script/tool/lib/src/pubspec_check_command.dart

@@ -70,7 +70,6 @@ class PubspecCheckCommand extends PackageLoopingCommand {
     File pubspecFile, {
     required String packageName,
   }) async {
-    const String indentation = '  ';
     final String contents = pubspecFile.readAsStringSync();
     final Pubspec? pubspec = _tryParsePubspec(contents);
     if (pubspec == null) {