Make "pub get" retry once a second when it fails. (#11882)

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

@@ -103,7 +103,7 @@ class PackagesTestCommand extends FlutterCommand {
   }
 
   @override
-  Future<Null> runCommand() => pub(<String>['run', 'test']..addAll(argResults.rest));
+  Future<Null> runCommand() => pub(<String>['run', 'test']..addAll(argResults.rest), retry: false);
 }
 
 class PackagesPassthroughCommand extends FlutterCommand {
@@ -124,5 +124,5 @@ class PackagesPassthroughCommand extends FlutterCommand {
   }
 
   @override
-  Future<Null> runCommand() => pub(argResults.rest);
+  Future<Null> runCommand() => pub(argResults.rest, retry: false);
 }

packages/flutter_tools/lib/src/dart/pub.dart

@@ -4,6 +4,8 @@
 
 import 'dart:async';
 
+import 'package:meta/meta.dart';
+
 import '../base/common.dart';
 import '../base/file_system.dart';
 import '../base/logger.dart';
@@ -55,7 +57,13 @@ Future<Null> pubGet({
     if (offline)
       args.add('--offline');
     try {
-      await pub(args, directory: directory, filter: _filterOverrideWarnings, failureMessage: 'pub $command failed');
+      await pub(
+        args,
+        directory: directory,
+        filter: _filterOverrideWarnings,
+        failureMessage: 'pub $command failed',
+        retry: true,
+      );
     } finally {
       status.stop();
     }
@@ -73,15 +81,29 @@ typedef String MessageFilter(String message);
 Future<Null> pub(List<String> arguments, {
   String directory,
   MessageFilter filter,
-  String failureMessage: 'pub failed'
+  String failureMessage: 'pub failed',
+  @required bool retry,
 }) async {
   final List<String> command = <String>[ sdkBinaryName('pub') ]..addAll(arguments);
-  final int code = await runCommandAndStreamOutput(
-    command,
-    workingDirectory: directory,
-    mapFunction: filter,
-    environment: <String, String>{ 'FLUTTER_ROOT': Cache.flutterRoot, _pubEnvironmentKey: _getPubEnvironmentValue() }
-  );
+  int attempts = 0;
+  int duration = 1;
+  int code;
+  while (true) {
+    attempts += 1;
+    code = await runCommandAndStreamOutput(
+      command,
+      workingDirectory: directory,
+      mapFunction: filter,
+      environment: <String, String>{ 'FLUTTER_ROOT': Cache.flutterRoot, _pubEnvironmentKey: _getPubEnvironmentValue() }
+    );
+    if (code != 69) // UNAVAILABLE in https://github.com/dart-lang/pub/blob/master/lib/src/exit_codes.dart
+      break;
+    printStatus('$failureMessage ($code) -- attempting retry $attempts in $duration second${ duration == 1 ? "" : "s"}...');
+    await new Future<Null>.delayed(new Duration(seconds: duration));
+    if (duration < 64)
+      duration *= 2;
+  }
+  assert(code != null);
   if (code != 0)
     throwToolExit('$failureMessage ($code)', exitCode: code);
 }

packages/flutter_tools/test/dart/pub_get_test.dart

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:async';
+
+import 'package:file/file.dart';
+import 'package:file/memory.dart';
+import 'package:flutter_tools/src/base/io.dart';
+import 'package:flutter_tools/src/dart/pub.dart';
+import 'package:mockito/mockito.dart';
+import 'package:process/process.dart';
+import 'package:quiver/testing/async.dart';
+import 'package:test/test.dart';
+
+import '../src/context.dart';
+
+void main() {
+  testUsingContext('pub get 69', () async {
+    String error;
+    new FakeAsync().run((FakeAsync time) {
+      pubGet(checkLastModified: false).then((Null value) {
+        error = 'test completed unexpectedly';
+      }, onError: (dynamic error) {
+        error = 'test failed unexpectedly';
+      });
+      expect(testLogger.statusText, '');
+      time.elapse(const Duration(milliseconds: 500));
+      expect(testLogger.statusText,
+        'Running "flutter packages get" in /...\n'
+        'pub get failed (69) -- attempting retry 1 in 1 second...\n'
+      );
+      time.elapse(const Duration(milliseconds: 500));
+      expect(testLogger.statusText,
+        'Running "flutter packages get" in /...\n'
+        'pub get failed (69) -- attempting retry 1 in 1 second...\n'
+        'pub get failed (69) -- attempting retry 2 in 2 seconds...\n'
+      );
+      time.elapse(const Duration(seconds: 1));
+      expect(testLogger.statusText,
+        'Running "flutter packages get" in /...\n'
+        'pub get failed (69) -- attempting retry 1 in 1 second...\n'
+        'pub get failed (69) -- attempting retry 2 in 2 seconds...\n'
+      );
+      time.elapse(const Duration(seconds: 100)); // from t=0 to t=100
+      expect(testLogger.statusText,
+        'Running "flutter packages get" in /...\n'
+        'pub get failed (69) -- attempting retry 1 in 1 second...\n'
+        'pub get failed (69) -- attempting retry 2 in 2 seconds...\n'
+        'pub get failed (69) -- attempting retry 3 in 4 seconds...\n' // at t=1
+        'pub get failed (69) -- attempting retry 4 in 8 seconds...\n' // at t=5
+        'pub get failed (69) -- attempting retry 5 in 16 seconds...\n' // at t=13
+        'pub get failed (69) -- attempting retry 6 in 32 seconds...\n' // at t=29
+        'pub get failed (69) -- attempting retry 7 in 64 seconds...\n' // at t=61
+      );
+      time.elapse(const Duration(seconds: 200)); // from t=0 to t=200
+      expect(testLogger.statusText,
+        'Running "flutter packages get" in /...\n'
+        'pub get failed (69) -- attempting retry 1 in 1 second...\n'
+        'pub get failed (69) -- attempting retry 2 in 2 seconds...\n'
+        'pub get failed (69) -- attempting retry 3 in 4 seconds...\n'
+        'pub get failed (69) -- attempting retry 4 in 8 seconds...\n'
+        'pub get failed (69) -- attempting retry 5 in 16 seconds...\n'
+        'pub get failed (69) -- attempting retry 6 in 32 seconds...\n'
+        'pub get failed (69) -- attempting retry 7 in 64 seconds...\n'
+        'pub get failed (69) -- attempting retry 8 in 64 seconds...\n' // at t=39
+        'pub get failed (69) -- attempting retry 9 in 64 seconds...\n' // at t=103
+        'pub get failed (69) -- attempting retry 10 in 64 seconds...\n' // at t=167
+      );
+    });
+    expect(testLogger.errorText, isEmpty);
+    expect(error, isNull);
+  }, overrides: <Type, Generator>{
+    ProcessManager: () => new MockProcessManager(69),
+    FileSystem: () => new MockFileSystem(),
+  });
+}
+
+typedef void StartCallback(List<dynamic> command);
+
+class MockProcessManager implements ProcessManager {
+  MockProcessManager(this.fakeExitCode);
+
+  final int fakeExitCode;
+
+  @override
+  Future<Process> start(
+    List<dynamic> command, {
+    String workingDirectory,
+    Map<String, String> environment,
+    bool includeParentEnvironment: true,
+    bool runInShell: false,
+    ProcessStartMode mode: ProcessStartMode.NORMAL,
+  }) {
+    return new Future<Process>.value(new MockProcess(fakeExitCode));
+  }
+
+  @override
+  dynamic noSuchMethod(Invocation invocation) => null;
+}
+
+class MockProcess implements Process {
+  MockProcess(this.fakeExitCode);
+
+  final int fakeExitCode;
+
+  @override
+  Stream<List<int>> get stdout => new MockStream<List<int>>();
+
+  @override
+  Stream<List<int>> get stderr => new MockStream<List<int>>();
+
+  @override
+  Future<int> get exitCode => new Future<int>.value(fakeExitCode);
+
+  @override
+  dynamic noSuchMethod(Invocation invocation) => null;
+}
+
+class MockStream<T> implements Stream<T> {
+  @override
+  Stream<S> transform<S>(StreamTransformer<T, S> streamTransformer) => new MockStream<S>();
+
+  @override
+  Stream<T> where(bool test(T event)) => new MockStream<T>();
+
+  @override
+  StreamSubscription<T> listen(void onData(T event), {Function onError, void onDone(), bool cancelOnError}) {
+    return new MockStreamSubscription<T>();
+  }
+
+  @override
+  dynamic noSuchMethod(Invocation invocation) => null;
+}
+
+class MockStreamSubscription<T> implements StreamSubscription<T> {
+  @override
+  Future<E> asFuture<E>([E futureValue]) => new Future<E>.value();
+
+  @override
+  Future<Null> cancel() => null;
+
+  @override
+  dynamic noSuchMethod(Invocation invocation) => null;
+}
+
+
+class MockFileSystem extends MemoryFileSystem {
+  @override
+  File file(dynamic path) {
+    return new MockFile();
+  }
+}
+
+class MockFile implements File {
+  @override
+  Future<RandomAccessFile> open({FileMode mode: FileMode.READ}) async {
+    return new MockRandomAccessFile();
+  }
+
+  @override
+  bool existsSync() => true;
+
+  @override
+  DateTime lastModifiedSync() => new DateTime(0);
+
+  @override
+  dynamic noSuchMethod(Invocation invocation) => null;
+}
+
+class MockRandomAccessFile extends Mock implements RandomAccessFile {}

packages/flutter_tools/test/dart_dependencies_test.dart

@@ -74,7 +74,7 @@ void main()  {
       }
     });
 
-    testUsingContext('does not change ASCI casing of path', () {
+    testUsingContext('does not change ASCII casing of path', () {
       final String testPath = fs.path.join(dataPath, 'asci_casing');
       final String mainPath = fs.path.join(testPath, 'main.dart');
       final String packagesPath = fs.path.join(testPath, '.packages');