[flutter_tools] re-use findProjectRoot on flutter command (#104850)

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

@@ -58,7 +58,6 @@ class PackagesCommand extends FlutterCommand {
 
 class PackagesGetCommand extends FlutterCommand {
   PackagesGetCommand(this.name, this.upgrade) {
-    requiresPubspecYaml();
     argParser.addFlag('offline',
       negatable: false,
       help: 'Use cached packages instead of accessing the network.',

packages/flutter_tools/lib/src/runner/flutter_command.dart

@@ -12,6 +12,7 @@ import '../application_package.dart';
 import '../base/common.dart';
 import '../base/context.dart';
 import '../base/io.dart' as io;
+import '../base/os.dart';
 import '../base/user_messages.dart';
 import '../base/utils.dart';
 import '../build_info.dart';
@@ -1475,16 +1476,12 @@ abstract class FlutterCommand extends Command<void> {
 
       // If there is no pubspec in the current directory, look in the parent
       // until one can be found.
-      bool changedDirectory = false;
-      while (!globals.fs.isFileSync('pubspec.yaml')) {
-        final Directory nextCurrent = globals.fs.currentDirectory.parent;
-        if (nextCurrent == null || nextCurrent.path == globals.fs.currentDirectory.path) {
-          throw ToolExit(userMessages.flutterNoPubspec);
-        }
-        globals.fs.currentDirectory = nextCurrent;
-        changedDirectory = true;
+      final String? path = findProjectRoot(globals.fs, globals.fs.currentDirectory.path);
+      if (path == null) {
+        throwToolExit(userMessages.flutterNoPubspec);
       }
-      if (changedDirectory) {
+      if (path != globals.fs.currentDirectory.path) {
+        globals.fs.currentDirectory = path;
         globals.printStatus('Changing current working directory to: ${globals.fs.currentDirectory.path}');
       }
     }

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

@@ -10,6 +10,7 @@ import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/commands/packages.dart';
 import 'package:flutter_tools/src/dart/pub.dart';
+import 'package:flutter_tools/src/project.dart';
 import 'package:flutter_tools/src/reporting/reporting.dart';
 import 'package:meta/meta.dart';
 import 'package:test/fake.dart';
@@ -77,6 +78,24 @@ void main() {
     FileSystem: () => fileSystem,
   });
 
+  testUsingContext('pub get on target directory', () async {
+    fileSystem.currentDirectory.childDirectory('target').createSync();
+    final Directory targetDirectory = fileSystem.currentDirectory.childDirectory('target');
+    targetDirectory.childFile('pubspec.yaml').createSync();
+
+    final PackagesGetCommand command = PackagesGetCommand('get', false);
+    final CommandRunner<void> commandRunner = createTestCommandRunner(command);
+
+    await commandRunner.run(<String>['get', targetDirectory.path]);
+    final FlutterProject rootProject = FlutterProject.fromDirectory(targetDirectory);
+    expect(rootProject.packageConfigFile.existsSync(), true);
+    expect(await rootProject.packageConfigFile.readAsString(), '{"configVersion":2,"packages":[]}');
+  }, overrides: <Type, Generator>{
+    Pub: () => pub,
+    ProcessManager: () => FakeProcessManager.any(),
+    FileSystem: () => fileSystem,
+  });
+
   testUsingContext("pub get skips example directory if it doesn't contain a pubspec.yaml", () async {
     fileSystem.currentDirectory.childFile('pubspec.yaml').createSync();
     fileSystem.currentDirectory.childDirectory('example').createSync(recursive: true);
@@ -116,7 +135,7 @@ class FakePub extends Fake implements Pub {
     bool shouldSkipThirdPartyGenerator = true,
     bool printProgress = true,
   }) async {
-    fileSystem.currentDirectory
+    fileSystem.directory(directory)
       .childDirectory('.dart_tool')
       .childFile('package_config.json')
       ..createSync(recursive: true)