enhance flutter upgrade to find project root (#5552)

* enhance flutter upgrade to find project root
fixes https://github.com/flutter/flutter/issues/2990

* address comments

* restore original formatting

* fix lints

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

@@ -5,6 +5,8 @@
 import 'dart:async';
 import 'dart:io';
 
+import 'package:path/path.dart' as path;
+
 import '../base/process.dart';
 import '../dart/pub.dart';
 import '../cache.dart';
@@ -61,9 +63,11 @@ class UpgradeCommand extends FlutterCommand {
     printStatus('');
     printStatus(FlutterVersion.getVersion(Cache.flutterRoot).toString());
 
-    if (FileSystemEntity.isFileSync('pubspec.yaml')) {
+    String projRoot = findProjectRoot();
+    if (projRoot != null) {
       printStatus('');
-      code = await pubGet(upgrade: true, checkLastModified: false);
+      code = await pubGet(
+          directory: projRoot, upgrade: true, checkLastModified: false);
 
       if (code != 0)
         return code;
@@ -86,4 +90,20 @@ class UpgradeCommand extends FlutterCommand {
       || _gitChangedRegex.hasMatch(line)
       || line == 'Fast-forward';
   }
+
+  /// Find and return the project root directory relative to the specified
+  /// directory or the current working directory if none specified.
+  /// Return `null` if the project root could not be found
+  /// or if the project root is the flutter repository root.
+  static String findProjectRoot([String directory]) {
+    directory ??= Directory.current.path;
+    while (true) {
+      if (FileSystemEntity.isFileSync(path.join(directory, 'pubspec.yaml')))
+        return directory;
+      String parent = FileSystemEntity.parentOf(directory);
+      if (directory == parent)
+        return null;
+      directory = parent;
+    }
+  }
 }

packages/flutter_tools/test/upgrade_test.dart

@@ -2,9 +2,19 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:async';
+import 'dart:io';
+
+import 'package:args/command_runner.dart';
+import 'package:flutter_tools/src/cache.dart';
+import 'package:flutter_tools/src/commands/create.dart';
 import 'package:flutter_tools/src/commands/upgrade.dart';
+import 'package:path/path.dart' as path;
 import 'package:test/test.dart';
 
+import 'src/common.dart';
+import 'src/context.dart';
+
 void main() {
   group('upgrade', () {
     bool _match(String line) => UpgradeCommand.matchesGitLine(line);
@@ -24,5 +34,42 @@ void main() {
       expect(_match('Updating 79cfe1e..5046107'), false);
       expect(_match('229 files changed, 6179 insertions(+), 3065 deletions(-)'), false);
     });
+
+    group('findProjectRoot', () {
+      Directory temp;
+
+      setUp(() async {
+        temp = Directory.systemTemp.createTempSync('flutter_tools');
+      });
+
+      tearDown(() {
+        temp.deleteSync(recursive: true);
+      });
+
+      Future<Null> createProject() async {
+        CreateCommand command = new CreateCommand();
+        CommandRunner runner = createTestCommandRunner(command);
+        int code = await runner.run(<String>['create', '--no-pub', temp.path]);
+        expect(code, 0);
+      }
+
+      testUsingContext('in project', () async {
+        await createProject();
+
+        String proj = temp.path;
+        expect(UpgradeCommand.findProjectRoot(proj), proj);
+        expect(UpgradeCommand.findProjectRoot(path.join(proj, 'lib')), proj);
+
+        String hello = path.join(Cache.flutterRoot, 'examples', 'hello_world');
+        expect(UpgradeCommand.findProjectRoot(hello), hello);
+        expect(UpgradeCommand.findProjectRoot(path.join(hello, 'lib')), hello);
+      });
+
+      testUsingContext('outside project', () async {
+        await createProject();
+        expect(UpgradeCommand.findProjectRoot(temp.parent.path), null);
+        expect(UpgradeCommand.findProjectRoot(Cache.flutterRoot), null);
+      });
+    });
   });
 }