[flutter_tools] unpin SDK deps when upgrading packages (#53429)

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

@@ -276,14 +276,30 @@ class UpdatePackagesCommand extends FlutterCommand {
         final File fakePackage = _pubspecFor(tempDir);
         fakePackage.createSync();
         fakePackage.writeAsStringSync(_generateFakePubspec(dependencies.values));
-        // First we run "pub upgrade" on this generated package:
+        // First, we create a synthetic flutter SDK so that transitive flutter SDK
+        // constraints are not affected by this upgrade.
+        final Directory temporaryFlutterSdk = createTemporaryFlutterSdk(
+          globals.fs,
+          globals.fs.directory(Cache.flutterRoot),
+          pubspecs,
+        );
+
+        // Next we run "pub upgrade" on this generated package:
         await pub.get(
           context: PubContext.updatePackages,
           directory: tempDir.path,
           upgrade: true,
           checkLastModified: false,
           offline: offline,
+          flutterRootOverride: temporaryFlutterSdk.path,
         );
+        // Cleanup the temporary SDK
+        try {
+          temporaryFlutterSdk.deleteSync(recursive: true);
+        } on FileSystemException {
+          // So sad...
+        }
+
         // Then we run "pub deps --style=compact" on the result. We pipe all the
         // output to tree.fill(), which parses it so that it can create a graph
         // of all the dependencies so that we can figure out the transitive
@@ -1170,7 +1186,8 @@ class PubspecDependency extends PubspecLine {
 
 /// Generates the File object for the pubspec.yaml file of a given Directory.
 File _pubspecFor(Directory directory) {
-  return globals.fs.file(globals.fs.path.join(directory.path, 'pubspec.yaml'));
+  return directory.fileSystem.file(
+    directory.fileSystem.path.join(directory.path, 'pubspec.yaml'));
 }
 
 /// Generates the source of a fake pubspec.yaml file given a list of
@@ -1334,3 +1351,77 @@ String _computeChecksum(Iterable<String> names, String getVersion(String name))
   }
   return ((upperCheck << 8) | lowerCheck).toRadixString(16).padLeft(4, '0');
 }
+
+/// Create a synthetic Flutter SDK so that pub version solving does not get
+/// stuck on the old versions.
+Directory createTemporaryFlutterSdk(FileSystem fileSystem, Directory realFlutter, List<PubspecYaml> pubspecs) {
+  final Set<String> currentPackages = realFlutter
+    .childDirectory('packages')
+    .listSync()
+    .whereType<Directory>()
+    .map((Directory directory) => fileSystem.path.basename(directory.path))
+    .toSet();
+
+  final Map<String, PubspecYaml> pubspecsByName = <String, PubspecYaml>{};
+  for (final PubspecYaml pubspec in pubspecs) {
+    pubspecsByName[pubspec.name] = pubspec;
+  }
+
+  final Directory directory = fileSystem.systemTempDirectory
+    .createTempSync('flutter_upgrade_sdk.')
+    ..createSync();
+  // Fill in version info.
+  realFlutter.childFile('version')
+    .copySync(directory.childFile('version').path);
+
+  // Directory structure should mirror the current Flutter SDK
+  final Directory packages = directory.childDirectory('packages');
+  for (final String flutterPackage in currentPackages) {
+    final File pubspecFile = packages
+      .childDirectory(flutterPackage)
+      .childFile('pubspec.yaml')
+      ..createSync(recursive: true);
+    final PubspecYaml pubspecYaml = pubspecsByName[flutterPackage];
+    final StringBuffer output = StringBuffer('name: $flutterPackage\n');
+
+    // Fill in SDK dependency constraint.
+    output.write('''
+environment:
+  sdk: ">=2.7.0 <3.0.0"
+''');
+
+    output.writeln('dependencies:');
+    for (final PubspecDependency dependency in pubspecYaml.dependencies) {
+      if (dependency.isTransitive || dependency.isDevDependency) {
+        continue;
+      }
+      if (dependency.kind == DependencyKind.sdk) {
+        output.writeln('  ${dependency.name}:\n    sdk: flutter');
+        continue;
+      }
+      output.writeln('  ${dependency.name}: any');
+    }
+    pubspecFile.writeAsStringSync(output.toString());
+  }
+
+  // Create the sky engine pubspec.yaml
+  directory
+    .childDirectory('bin')
+    .childDirectory('cache')
+    .childDirectory('pkg')
+    .childDirectory('sky_engine')
+    .childFile('pubspec.yaml')
+    ..createSync(recursive: true)
+    ..writeAsStringSync('''
+name: sky_engine
+version: 0.0.99
+author: Flutter Authors <flutter-dev@googlegroups.com>
+description: Dart SDK extensions for dart:ui
+homepage: http://flutter.io
+# sky_engine requires sdk_ext support in the analyzer which was added in 1.11.x
+environment:
+  sdk: '>=1.11.0 <3.0.0'
+''');
+
+  return directory;
+}

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

@@ -96,6 +96,7 @@ abstract class Pub {
     bool offline = false,
     bool checkLastModified = true,
     bool skipPubspecYamlCheck = false,
+    String flutterRootOverride,
   });
 
   /// Runs pub in 'batch' mode.
@@ -143,6 +144,7 @@ class _DefaultPub implements Pub {
     bool offline = false,
     bool checkLastModified = true,
     bool skipPubspecYamlCheck = false,
+    String flutterRootOverride,
   }) async {
     directory ??= globals.fs.currentDirectory.path;
 
@@ -178,6 +180,7 @@ class _DefaultPub implements Pub {
           filter: _filterOverrideWarnings,
           failureMessage: 'pub $command failed',
           retry: true,
+          flutterRootOverride: flutterRootOverride,
         );
         status.stop();
       // The exception is rethrown, so don't catch only Exceptions.
@@ -231,6 +234,7 @@ class _DefaultPub implements Pub {
     String failureMessage = 'pub failed',
     @required bool retry,
     bool showTraceForErrors,
+    String flutterRootOverride,
   }) async {
     showTraceForErrors ??= await globals.isRunningOnBot;
 
@@ -259,7 +263,7 @@ class _DefaultPub implements Pub {
         _pubCommand(arguments),
         workingDirectory: directory,
         mapFunction: filterWrapper, // may set versionSolvingFailed, lastPubMessage
-        environment: await _createPubEnvironment(context),
+        environment: await _createPubEnvironment(context, flutterRootOverride),
       );
       String message;
       switch (code) {
@@ -348,9 +352,9 @@ typedef MessageFilter = String Function(String message);
 ///
 /// [context] provides extra information to package server requests to
 /// understand usage.
-Future<Map<String, String>> _createPubEnvironment(PubContext context) async {
+Future<Map<String, String>> _createPubEnvironment(PubContext context, [ String flutterRootOverride ]) async {
   final Map<String, String> environment = <String, String>{
-    'FLUTTER_ROOT': Cache.flutterRoot,
+    'FLUTTER_ROOT': flutterRootOverride ?? Cache.flutterRoot,
     _pubEnvironmentKey: await _getPubEnvironmentValue(context),
   };
   final String pubCache = _getRootPubCacheIfAvailable();

packages/flutter_tools/test/general.shard/update_packages_test.dart

+// Copyright 2014 The Flutter 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 'package:file/memory.dart';
+import 'package:file_testing/file_testing.dart';
+import 'package:flutter_tools/src/base/file_system.dart';
+import 'package:flutter_tools/src/commands/update_packages.dart';
+
+import '../src/common.dart';
+
+// An example pubspec.yaml from flutter, not necessary for it to be up to date.
+const String kFlutterPubspecYaml = r'''
+name: flutter
+author: Flutter Authors <flutter-dev@googlegroups.com>
+description: A framework for writing Flutter applications
+homepage: http://flutter.dev
+
+environment:
+  # The pub client defaults to an <2.0.0 sdk constraint which we need to explicitly overwrite.
+  sdk: ">=2.2.2 <3.0.0"
+
+dependencies:
+  # To update these, use "flutter update-packages --force-upgrade".
+  collection: 1.14.11
+  meta: 1.1.8
+  typed_data: 1.1.6
+  vector_math: 2.0.8
+
+  sky_engine:
+    sdk: flutter
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter
+  flutter_goldens:
+    sdk: flutter
+  mockito: 4.1.1
+
+  archive: 2.0.11 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
+
+# PUBSPEC CHECKSUM: 1437
+''';
+
+void main() {
+  testWithoutContext('createTemporaryFlutterSdk creates an unpinned flutter SDK', () {
+    final FileSystem fileSystem = MemoryFileSystem.test();
+
+    // Setup simplified FLutter SDK.
+    final Directory flutterSdk = fileSystem.directory('flutter')
+      ..createSync();
+    // Create version file
+    flutterSdk.childFile('version').writeAsStringSync('1.2.3');
+    // Create a pubspec file
+    final Directory flutter = flutterSdk
+      .childDirectory('packages')
+      .childDirectory('flutter')
+      ..createSync(recursive: true);
+    flutter
+      .childFile('pubspec.yaml')
+      .writeAsStringSync(kFlutterPubspecYaml);
+
+    // Create already parsed pubspecs.
+    final PubspecYaml flutterPubspec = PubspecYaml(flutter);
+
+    final Directory result = createTemporaryFlutterSdk(
+      fileSystem,
+      flutterSdk,
+      <PubspecYaml>[flutterPubspec],
+    );
+
+    expect(result, exists);
+
+    // The version file exists.
+    expect(result.childFile('version'), exists);
+    expect(result.childFile('version').readAsStringSync(), '1.2.3');
+
+    // The sky_engine package exists
+    expect(fileSystem.directory('${result.path}/bin/cache/pkg/sky_engine'), exists);
+
+    // The flutter pubspec exists
+    final File pubspecFile = fileSystem.file('${result.path}/packages/flutter/pubspec.yaml');
+    expect(pubspecFile, exists);
+
+    // The flutter pubspec contains `any` dependencies.
+    final PubspecYaml outputPubspec = PubspecYaml(pubspecFile.parent);
+    expect(outputPubspec.name, 'flutter');
+    expect(outputPubspec.dependencies.first.name, 'collection');
+    expect(outputPubspec.dependencies.first.version, 'any');
+  });
+}

packages/flutter_tools/test/src/throwing_pub.dart

@@ -28,6 +28,7 @@ class ThrowingPub implements Pub {
     bool offline = false,
     bool checkLastModified = true,
     bool skipPubspecYamlCheck = false,
+    String flutterRootOverride,
   }) {
     throw UnsupportedError('Attempted to invoke pub during test.');
   }