[flutter_tools] enable `flutter upgrade` to support force pushed branches (#55594)

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

@@ -100,7 +100,12 @@ class UpgradeCommandRunner {
     @required FlutterVersion flutterVersion,
     @required bool testFlow,
   }) async {
-    await verifyUpstreamConfigured();
+    final String upstreamRevision = await fetchRemoteRevision();
+    if (flutterVersion.frameworkRevision == upstreamRevision) {
+      globals.printStatus('Flutter is already up to date on channel ${flutterVersion.channel}');
+      globals.printStatus('$flutterVersion');
+      return;
+    }
     if (!force && gitTagVersion == const GitTagVersion.unknown()) {
       // If the commit is a recognized branch and not master,
       // explain that we are avoiding potential damage.
@@ -132,12 +137,8 @@ class UpgradeCommandRunner {
     }
     recordState(flutterVersion);
     await upgradeChannel(flutterVersion);
-    final bool alreadyUpToDate = await attemptFastForward(flutterVersion);
-    if (alreadyUpToDate) {
-      // If the upgrade was a no op, then do not continue with the second half.
-      globals.printStatus('Flutter is already up to date on channel ${flutterVersion.channel}');
-      globals.printStatus('$flutterVersion');
-    } else if (!testFlow) {
+    await attemptReset(flutterVersion, upstreamRevision);
+    if (!testFlow) {
       await flutterUpgradeContinue();
     }
   }
@@ -199,16 +200,25 @@ class UpgradeCommandRunner {
     return false;
   }
 
-  /// Check if there is an upstream repository configured.
+  /// Returns the remote HEAD revision.
   ///
   /// Exits tool if there is no upstream.
-  Future<void> verifyUpstreamConfigured() async {
+  Future<String> fetchRemoteRevision() async {
+    String revision;
     try {
+      // Fetch upstream branch's commits and tags
       await processUtils.run(
-        <String>[ 'git', 'rev-parse', '@{u}'],
+        <String>['git', 'fetch', '--tags'],
         throwOnError: true,
         workingDirectory: workingDirectory,
       );
+      // '@{u}' means upstream HEAD
+      final RunResult result = await processUtils.run(
+          <String>[ 'git', 'rev-parse', '--verify', '@{u}'],
+          throwOnError: true,
+          workingDirectory: workingDirectory,
+      );
+      revision = result.stdout.trim();
     } on Exception {
       throwToolExit(
         'Unable to upgrade Flutter: no origin repository configured. '
@@ -216,6 +226,7 @@ class UpgradeCommandRunner {
         "https://github.com/flutter/flutter' in $workingDirectory",
       );
     }
+    return revision;
   }
 
   /// Attempts to upgrade the channel.
@@ -227,33 +238,20 @@ class UpgradeCommandRunner {
     await ChannelCommand.upgradeChannel();
   }
 
-  /// Attempts to rebase the upstream onto the local branch.
-  ///
-  /// If there haven't been any hot fixes or local changes, this is equivalent
-  /// to a fast-forward.
+  /// Attempts a hard reset to the given revision.
   ///
-  /// If the fast forward lands us on the same channel and revision, then
-  /// returns true, otherwise returns false.
-  Future<bool> attemptFastForward(FlutterVersion oldFlutterVersion) async {
-    final int code = await processUtils.stream(
-      <String>['git', 'pull', '--ff-only'],
+  /// This is a reset instead of fast forward because if we are on a release
+  /// branch with cherry picks, there may not be a direct fast-forward route
+  /// to the next release.
+  Future<void> attemptReset(FlutterVersion oldFlutterVersion, String newRevision) async {
+    final RunResult result = await processUtils.run(
+      <String>['git', 'reset', '--hard', newRevision],
+      throwOnError: true,
       workingDirectory: workingDirectory,
-      mapFunction: (String line) => matchesGitLine(line) ? null : line,
     );
-    if (code != 0) {
-      throwToolExit(null, exitCode: code);
+    if (result.exitCode != 0) {
+      throwToolExit(null, exitCode: result.exitCode);
     }
-
-    // Check if the upgrade did anything.
-    bool alreadyUpToDate = false;
-    try {
-      final FlutterVersion newFlutterVersion = FlutterVersion(const SystemClock(), workingDirectory);
-      alreadyUpToDate = newFlutterVersion.channel == oldFlutterVersion.channel &&
-        newFlutterVersion.frameworkRevision == oldFlutterVersion.frameworkRevision;
-    } on Exception catch (e) {
-      globals.printTrace('Failed to determine FlutterVersion after upgrade fast-forward: $e');
-    }
-    return alreadyUpToDate;
   }
 
   /// Update the engine repository and precache all artifacts.
@@ -300,18 +298,4 @@ class UpgradeCommandRunner {
       allowReentrantFlutter: true,
     );
   }
-
-  //  dev/benchmarks/complex_layout/lib/main.dart        |  24 +-
-  static final RegExp _gitDiffRegex = RegExp(r' (\S+)\s+\|\s+\d+ [+-]+');
-
-  //  rename {packages/flutter/doc => dev/docs}/styles.html (92%)
-  //  delete mode 100644 doc/index.html
-  //  create mode 100644 dev/integration_tests/flutter_gallery/lib/gallery/demo.dart
-  static final RegExp _gitChangedRegex = RegExp(r' (rename|delete mode|create mode) .+');
-
-  static bool matchesGitLine(String line) {
-    return _gitDiffRegex.hasMatch(line)
-      || _gitChangedRegex.hasMatch(line)
-      || line == 'Fast-forward';
-  }
 }

packages/flutter_tools/test/commands.shard/permeable/upgrade_test.dart

@@ -5,7 +5,6 @@
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/io.dart';
 
-import 'package:flutter_tools/src/base/os.dart';
 import 'package:flutter_tools/src/cache.dart';
 import 'package:flutter_tools/src/commands/upgrade.dart';
 import 'package:flutter_tools/src/convert.dart';
@@ -134,7 +133,10 @@ void main() {
     });
 
     testUsingContext("Doesn't continue on known tag, dev branch, no force, already up-to-date", () async {
+      const String revision = 'abc123';
+      when(flutterVersion.frameworkRevision).thenReturn(revision);
       fakeCommandRunner.alreadyUpToDate = true;
+      fakeCommandRunner.remoteRevision = revision;
       final Future<FlutterCommandResult> result = fakeCommandRunner.runCommand(
         force: false,
         continueFlow: false,
@@ -159,16 +161,26 @@ void main() {
       Platform: () => fakePlatform,
     });
 
-    testUsingContext('verifyUpstreamConfigured', () async {
-      when(globals.processManager.run(
-        <String>['git', 'rev-parse', '@{u}'],
+    testUsingContext('fetchRemoteRevision', () async {
+      const String revision = 'abc123';
+      when(processManager.run(
+        <String>['git', 'fetch', '--tags'],
         environment:anyNamed('environment'),
         workingDirectory: anyNamed('workingDirectory')),
       ).thenAnswer((Invocation invocation) async {
         return FakeProcessResult()
           ..exitCode = 0;
       });
-      await realCommandRunner.verifyUpstreamConfigured();
+      when(processManager.run(
+        <String>['git', 'rev-parse', '--verify', '@{u}'],
+        environment:anyNamed('environment'),
+        workingDirectory: anyNamed('workingDirectory')),
+      ).thenAnswer((Invocation invocation) async {
+        return FakeProcessResult()
+          ..exitCode = 0
+          ..stdout = revision;
+      });
+      expect(await realCommandRunner.fetchRemoteRevision(), revision);
     }, overrides: <Type, Generator>{
       ProcessManager: () => processManager,
       Platform: () => fakePlatform,
@@ -284,58 +296,6 @@ void main() {
       });
     });
   });
-
-  group('matchesGitLine', () {
-    setUpAll(() {
-      Cache.disableLocking();
-    });
-
-    bool _match(String line) => UpgradeCommandRunner.matchesGitLine(line);
-
-    test('regex match', () {
-      expect(_match(' .../flutter_gallery/lib/demo/buttons_demo.dart    | 10 +--'), true);
-      expect(_match(' dev/benchmarks/complex_layout/lib/main.dart        |  24 +-'), true);
-
-      expect(_match(' rename {packages/flutter/doc => dev/docs}/styles.html (92%)'), true);
-      expect(_match(' delete mode 100644 doc/index.html'), true);
-      expect(_match(' create mode 100644 dev/integration_tests/flutter_gallery/lib/gallery/demo.dart'), true);
-
-      expect(_match('Fast-forward'), true);
-    });
-
-    test("regex doesn't match", () {
-      expect(_match('Updating 79cfe1e..5046107'), false);
-      expect(_match('229 files changed, 6179 insertions(+), 3065 deletions(-)'), false);
-    });
-
-    group('findProjectRoot', () {
-      Directory tempDir;
-
-      setUp(() async {
-        tempDir = globals.fs.systemTempDirectory.createTempSync('flutter_tools_upgrade_test.');
-      });
-
-      tearDown(() {
-        tryToDelete(tempDir);
-      });
-
-      testUsingContext('in project', () async {
-        final String projectPath = await createProject(tempDir);
-        expect(findProjectRoot(projectPath), projectPath);
-        expect(findProjectRoot(globals.fs.path.join(projectPath, 'lib')), projectPath);
-
-        final String hello = globals.fs.path.join(Cache.flutterRoot, 'examples', 'hello_world');
-        expect(findProjectRoot(hello), hello);
-        expect(findProjectRoot(globals.fs.path.join(hello, 'lib')), hello);
-      });
-
-      testUsingContext('outside project', () async {
-        final String projectPath = await createProject(tempDir);
-        expect(findProjectRoot(globals.fs.directory(projectPath).parent.path), null);
-        expect(findProjectRoot(Cache.flutterRoot), null);
-      });
-    });
-  });
 }
 
 class FakeUpgradeCommandRunner extends UpgradeCommandRunner {
@@ -343,8 +303,10 @@ class FakeUpgradeCommandRunner extends UpgradeCommandRunner {
 
   bool alreadyUpToDate = false;
 
+  String remoteRevision = '';
+
   @override
-  Future<void> verifyUpstreamConfigured() async {}
+  Future<String> fetchRemoteRevision() async => remoteRevision;
 
   @override
   Future<bool> hasUncomittedChanges() async => willHaveUncomittedChanges;
@@ -353,7 +315,7 @@ class FakeUpgradeCommandRunner extends UpgradeCommandRunner {
   Future<void> upgradeChannel(FlutterVersion flutterVersion) async {}
 
   @override
-  Future<bool> attemptFastForward(FlutterVersion flutterVersion) async => alreadyUpToDate;
+  Future<bool> attemptReset(FlutterVersion flutterVersion, String newRevision) async => alreadyUpToDate;
 
   @override
   Future<void> precacheArtifacts() async {}

packages/flutter_tools/test/integration.shard/downgrade_upgrade_integration_test.dart

@@ -57,8 +57,7 @@ void main() {
       'git', 'config', '--system', 'core.longpaths', 'true',
     ]);
 
-    print('Step 1');
-    // Step 1. Clone the dev branch of flutter into the test directory.
+    print('Step 1 - clone the $_kBranch of flutter into the test directory');
     exitCode = await processUtils.stream(<String>[
       'git',
       'clone',
@@ -66,8 +65,7 @@ void main() {
     ], workingDirectory: parentDirectory.path, trace: true);
     expect(exitCode, 0);
 
-    print('Step 2');
-    // Step 2. Switch to the dev branch.
+    print('Step 2 - switch to the $_kBranch');
     exitCode = await processUtils.stream(<String>[
       'git',
       'checkout',
@@ -78,8 +76,7 @@ void main() {
     ], workingDirectory: testDirectory.path, trace: true);
     expect(exitCode, 0);
 
-    print('Step 3');
-    // Step 3. Revert to a prior version.
+    print('Step 3 - revert back to $_kInitialVersion');
     exitCode = await processUtils.stream(<String>[
       'git',
       'reset',
@@ -88,9 +85,8 @@ void main() {
     ], workingDirectory: testDirectory.path, trace: true);
     expect(exitCode, 0);
 
-    print('Step 4');
-    // Step 4. Upgrade to the newest stable. This should update the persistent
-    // tool state with the sha for v1.14.3
+    print('Step 4 - upgrade to the newest $_kBranch');
+    // This should update the persistent tool state with the sha for HEAD
     exitCode = await processUtils.stream(<String>[
       flutterBin,
       'upgrade',
@@ -99,8 +95,7 @@ void main() {
     ], workingDirectory: testDirectory.path, trace: true);
     expect(exitCode, 0);
 
-    print('Step 5');
-    // Step 5. Verify that the version is different.
+    print('Step 5 - verify that the version is different');
     final RunResult versionResult = await processUtils.run(<String>[
       'git',
       'describe',
@@ -111,8 +106,9 @@ void main() {
       '--tags',
     ], workingDirectory: testDirectory.path);
     expect(versionResult.stdout, isNot(contains(_kInitialVersion)));
+    print('current version is ${versionResult.stdout.trim()}\ninitial was $_kInitialVersion');
 
-    print('Step 6');
+    print('Step 6 - downgrade back to the initial version');
     // Step 6. Downgrade back to initial version.
     exitCode = await processUtils.stream(<String>[
        flutterBin,
@@ -122,7 +118,7 @@ void main() {
     ], workingDirectory: testDirectory.path, trace: true);
     expect(exitCode, 0);
 
-    print('Step 7');
+    print('Step 7 - verify downgraded version matches original version');
     // Step 7. Verify downgraded version matches original version.
     final RunResult oldVersionResult = await processUtils.run(<String>[
       'git',
@@ -134,5 +130,6 @@ void main() {
       '--tags',
     ], workingDirectory: testDirectory.path);
     expect(oldVersionResult.stdout, contains(_kInitialVersion));
+    print('current version is ${oldVersionResult.stdout.trim()}\ninitial was $_kInitialVersion');
   });
 }