Use already downloaded dart sdk for frontend_server. (#14702)

* Use already downloaded dart sdk for frontend_server.

This is follow-up to https://github.com/flutter/flutter/pull/14610

* Remove reference to engine dart-sdk from artifacts

* Remove unused imports

* WIP to switch back to solution where dart sdk is downloaded into bin/cache/dart-sdk, but it is 'flutter precache -a' that can download all dart sdks for other platforms under bin/cache/artifacts/engine/<platform>/dart-sdk

* Download all dart sdks when 'flutter precache -a'

bin/internal/dart-sdk.version

-2.0.0-dev.22.0

packages/flutter_tools/lib/src/artifacts.dart

@@ -24,7 +24,6 @@ enum Artifact {
   platformLibrariesJson,
   flutterPatchedSdkPath,
   frontendServerSnapshotForEngineDartSdk,
-  engineDartSdkPath,
 }
 
 String _artifactToFileName(Artifact artifact) {
@@ -52,8 +51,6 @@ String _artifactToFileName(Artifact artifact) {
     case Artifact.flutterPatchedSdkPath:
       assert(false, 'No filename for sdk path, should not be invoked');
       return null;
-    case Artifact.engineDartSdkPath:
-      return 'dart-sdk';
     case Artifact.frontendServerSnapshotForEngineDartSdk:
       return 'frontend_server.dart.snapshot';
   }
@@ -164,7 +161,6 @@ class CachedArtifacts extends Artifacts {
       case Artifact.vmSnapshotData:
       case Artifact.isolateSnapshotData:
       case Artifact.frontendServerSnapshotForEngineDartSdk:
-      case Artifact.engineDartSdkPath:
         final String engineArtifactsPath = cache.getArtifactDirectory('engine').path;
         final String platformDirName = getNameForTargetPlatform(platform);
         return fs.path.join(engineArtifactsPath, platformDirName, _artifactToFileName(artifact));
@@ -248,8 +244,6 @@ class LocalEngineArtifacts extends Artifacts {
         return _getFlutterPatchedSdkPath();
       case Artifact.frontendServerSnapshotForEngineDartSdk:
         return fs.path.join(_hostEngineOutPath, 'gen', _artifactToFileName(artifact));
-      case Artifact.engineDartSdkPath:
-        return fs.path.join(_hostEngineOutPath, 'dart-sdk');
     }
     assert(false, 'Invalid artifact $artifact.');
     return null;

packages/flutter_tools/lib/src/cache.dart

@@ -8,12 +8,10 @@ import 'package:meta/meta.dart';
 
 import 'base/context.dart';
 import 'base/file_system.dart';
-import 'base/io.dart';
 import 'base/logger.dart';
 import 'base/net.dart';
 import 'base/os.dart';
 import 'base/platform.dart';
-import 'base/process_manager.dart';
 import 'globals.dart';
 
 /// A wrapper around the `bin/cache/` directory.
@@ -118,32 +116,6 @@ class Cache {
     return _engineRevision;
   }
 
-  String _engineDartVersion;
-
-  String get engineDartVersion {
-    if (_engineDartVersion == null) {
-      final Directory engineDirectory = getArtifactDirectory('engine');
-
-      List<String> dartSdkBinParts;
-      if (platform.isLinux) {
-        dartSdkBinParts = <String>['linux-x64', 'dart-sdk', 'bin', 'dart'];
-      } else if (platform.isMacOS) {
-        dartSdkBinParts = <String>['darwin-x64', 'dart-sdk', 'bin', 'dart'];
-      } else if (platform.isWindows) {
-        dartSdkBinParts = <String>['windows-x64', 'dart-sdk', 'bin', 'dart.exe'];
-      } else {
-        // Unknown platform, we can't derive version.
-        return null;
-      }
-      final File dartSdkBin = engineDirectory.childFile(fs.path.joinAll(dartSdkBinParts));
-      final ProcessResult result = processManager.runSync(<String>[dartSdkBin.path, '--version']);
-      // https://github.com/dart-lang/sdk/issues/31481
-      // We can use the process utils directly when this is fixed instead of parsing stderr.
-      _engineDartVersion = result.stderr.trim().replaceAll('Dart VM version: ', '');
-    }
-    return _engineDartVersion;
-  }
-
   static Cache get instance => context[Cache];
 
   /// Return the top-level directory in the cache; this is `bin/cache`.
@@ -364,7 +336,8 @@ class FlutterEngine extends CachedArtifact {
         ..addAll(_linuxBinaryDirs)
         ..addAll(_windowsBinaryDirs)
         ..addAll(_androidBinaryDirs)
-        ..addAll(_iosBinaryDirs);
+        ..addAll(_iosBinaryDirs)
+        ..addAll(_dartSdks);
     else if (platform.isLinux)
       binaryDirs
         ..addAll(_linuxBinaryDirs)
@@ -384,7 +357,6 @@ class FlutterEngine extends CachedArtifact {
 
   List<List<String>> get _osxBinaryDirs => <List<String>>[
     <String>['darwin-x64', 'darwin-x64/artifacts.zip'],
-    <String>['darwin-x64', 'dart-sdk-darwin-x64.zip'],
     <String>['android-arm-profile/darwin-x64', 'android-arm-profile/darwin-x64.zip'],
     <String>['android-arm-release/darwin-x64', 'android-arm-release/darwin-x64.zip'],
     <String>['android-arm64-profile/darwin-x64', 'android-arm64-profile/darwin-x64.zip'],
@@ -393,7 +365,6 @@ class FlutterEngine extends CachedArtifact {
 
   List<List<String>> get _linuxBinaryDirs => <List<String>>[
     <String>['linux-x64', 'linux-x64/artifacts.zip'],
-    <String>['linux-x64', 'dart-sdk-linux-x64.zip'],
     <String>['android-arm-profile/linux-x64', 'android-arm-profile/linux-x64.zip'],
     <String>['android-arm-release/linux-x64', 'android-arm-release/linux-x64.zip'],
     <String>['android-arm64-profile/linux-x64', 'android-arm64-profile/linux-x64.zip'],
@@ -402,7 +373,6 @@ class FlutterEngine extends CachedArtifact {
 
   List<List<String>> get _windowsBinaryDirs => <List<String>>[
     <String>['windows-x64', 'windows-x64/artifacts.zip'],
-    <String>['windows-x64', 'dart-sdk-windows-x64.zip'],
     <String>['android-arm-profile/windows-x64', 'android-arm-profile/windows-x64.zip'],
     <String>['android-arm-release/windows-x64', 'android-arm-release/windows-x64.zip'],
     <String>['android-arm64-profile/windows-x64', 'android-arm64-profile/windows-x64.zip'],
@@ -426,6 +396,12 @@ class FlutterEngine extends CachedArtifact {
     <String>['ios-release', 'ios-release/artifacts.zip'],
   ];
 
+  List<List<String>> get _dartSdks => <List<String>> [
+    <String>['darwin-x64', 'dart-sdk-darwin-x64.zip'],
+    <String>['linux-x64', 'dart-sdk-linux-x64.zip'],
+    <String>['windows-x64', 'dart-sdk-windows-x64.zip'],
+  ];
+
   @override
   bool isUpToDateInner() {
     final Directory pkgDir = cache.getCacheDir('pkg');

packages/flutter_tools/lib/src/compile.dart

@@ -8,22 +8,14 @@ import 'dart:convert';
 import 'package:usage/uuid/uuid.dart';
 
 import 'artifacts.dart';
-import 'base/common.dart';
 import 'base/file_system.dart';
 import 'base/io.dart';
 import 'base/process_manager.dart';
+import 'dart/sdk.dart';
 import 'globals.dart';
 
 String _dartExecutable() {
-  final String engineDartSdkPath = artifacts.getArtifactPath(
-    Artifact.engineDartSdkPath
-  );
-  if (!fs.isDirectorySync(engineDartSdkPath)) {
-    throwToolExit('No dart sdk Flutter host engine build found at $engineDartSdkPath.\n'
-      'Note that corresponding host engine build is required even when targeting particular device platforms.',
-      exitCode: 2);
-  }
-  return fs.path.join(engineDartSdkPath, 'bin', 'dart');
+  return fs.path.join(dartSdkPath, 'bin', 'dart');
 }
 
 class _StdoutHandler {

packages/flutter_tools/lib/src/doctor.dart

@@ -258,8 +258,7 @@ class _FlutterValidator extends DoctorValidator {
       '(${version.frameworkAge}), ${version.frameworkDate}'
     ));
     messages.add(new ValidationMessage('Engine revision ${version.engineRevisionShort}'));
-    messages.add(new ValidationMessage('Tools Dart version ${version.dartSdkVersion}'));
-    messages.add(new ValidationMessage('Engine Dart version ${version.engineDartVersion}'));
+    messages.add(new ValidationMessage('Dart version ${version.dartSdkVersion}'));
     final String genSnapshotPath =
       artifacts.getArtifactPath(Artifact.genSnapshot);
 

packages/flutter_tools/lib/src/version.dart

@@ -83,7 +83,6 @@ class FlutterVersion {
   String get frameworkDate => frameworkCommitDate;
 
   String get dartSdkVersion => Cache.instance.dartSdkVersion.split(' ')[0];
-  String get engineDartVersion => Cache.instance.engineDartVersion.split(' ')[0];
 
   String get engineRevision => Cache.instance.engineRevision;
   String get engineRevisionShort => _shortGitRevision(engineRevision);

packages/flutter_tools/test/artifacts_test.dart

@@ -89,10 +89,6 @@ void main() {
           artifacts.getArtifactPath(Artifact.flutterTester),
           fs.path.join(tempDir.path, 'out', 'android_debug_unopt', 'flutter_tester')
       );
-      expect(
-        artifacts.getArtifactPath(Artifact.engineDartSdkPath),
-        fs.path.join(tempDir.path, 'out', 'host_debug_unopt', 'dart-sdk')
-      );
     }, overrides: <Type, Generator> {
       Platform: () => new FakePlatform(operatingSystem: 'linux')
     });

packages/flutter_tools/test/version_test.dart

@@ -61,12 +61,6 @@ void main() {
       _expectVersionMessage('');
     });
 
-    testFlutterVersion('prints non-empty version for engine Dart SDK', () async {
-      final FlutterVersion version = FlutterVersion.instance;
-      final String engineDartVersion = version.engineDartVersion;
-      expect(engineDartVersion.length, greaterThan(0));
-    });
-
     testFlutterVersion('does not ping server when version stamp is up-to-date', () async {
       final FlutterVersion version = FlutterVersion.instance;