Reland "[ddc] Add web library environment variables"

This is a reland of fb36bba5f2 with
a fix to the ordering to ensure all the expectations run.

Original change's description:
> [ddc] Add web library environment variables
>
> Ensure frontend server builds for the `DevCompilerTarget` add the
> environment variables needed for `bool.fromEnvironment()` calls for
> conditional imports.
>
> Change-Id: Ifd372c1cf385fc843534d85af1ac9ae75a6285b8
> Fixes: https://github.com/dart-lang/sdk/issues/47207
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/213802
> Commit-Queue: Nicholas Shahan <nshahan@google.com>
> Reviewed-by: Johnni Winther <johnniwinther@google.com>

Change-Id: Id88aeaf0ddc783936d413c06099df031bc7cb0a7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/214224
Reviewed-by: Anna Gringauze <annagrin@google.com>
Commit-Queue: Nicholas Shahan <nshahan@google.com>

pkg/dev_compiler/lib/src/compiler/shared_command.dart

@@ -23,34 +23,6 @@ import 'module_builder.dart';
 /// This file should only implement functionality that does not depend on
 /// Analyzer/Kernel imports.
 
-/// Variables that indicate which libraries are available in dev compiler.
-// TODO(jmesserly): provide an option to compile without dart:html & friends?
-Map<String, String> sdkLibraryVariables = {
-  'dart.isVM': 'false',
-  'dart.library.async': 'true',
-  'dart.library.core': 'true',
-  'dart.library.collection': 'true',
-  'dart.library.convert': 'true',
-  // TODO(jmesserly): this is not really supported in dart4web other than
-  // `debugger()`
-  'dart.library.developer': 'true',
-  'dart.library.io': 'false',
-  'dart.library.isolate': 'false',
-  'dart.library.js': 'true',
-  'dart.library.js_util': 'true',
-  'dart.library.math': 'true',
-  'dart.library.mirrors': 'false',
-  'dart.library.typed_data': 'true',
-  'dart.library.indexed_db': 'true',
-  'dart.library.html': 'true',
-  'dart.library.html_common': 'true',
-  'dart.library.svg': 'true',
-  'dart.library.ui': 'false',
-  'dart.library.web_audio': 'true',
-  'dart.library.web_gl': 'true',
-  'dart.library.web_sql': 'true',
-};
-
 /// Compiler options for the `dartdevc` backend.
 class SharedCompilerOptions {
   /// Whether to emit the source mapping file.

pkg/dev_compiler/lib/src/kernel/command.dart

@@ -819,7 +819,8 @@ Map<String, String> parseAndRemoveDeclaredVariables(List<String> args) {
   }
 
   // Add platform defined variables
-  declaredVariables.addAll(sdkLibraryVariables);
+  // TODO(47243) Remove when all code paths read these from the `Target`.
+  declaredVariables.addAll(sdkLibraryEnvironmentDefines);
 
   return declaredVariables;
 }

pkg/dev_compiler/lib/src/kernel/expression_compiler_worker.dart

@@ -12,6 +12,8 @@ import 'dart:isolate';
 import 'package:args/args.dart';
 import 'package:build_integration/file_system/multi_root.dart';
 import 'package:dev_compiler/dev_compiler.dart';
+import 'package:dev_compiler/src/kernel/target.dart'
+    show sdkLibraryEnvironmentDefines;
 import 'package:front_end/src/api_prototype/file_system.dart';
 import 'package:front_end/src/api_unstable/ddc.dart';
 import 'package:kernel/ast.dart' show Component, Library;
@@ -206,7 +208,7 @@ class ExpressionCompilerWorker {
     @required Uri sdkSummary,
     @required FileSystem fileSystem,
     Uri packagesFile,
-    Map<String, String> environmentDefines = const {},
+    Map<String, String> environmentDefines,
     Map<ExperimentalFlag, bool> explicitExperimentalFlags = const {},
     Uri sdkRoot,
     bool trackWidgetCreation = false,
@@ -228,7 +230,11 @@ class ExpressionCompilerWorker {
           TargetFlags(trackWidgetCreation: trackWidgetCreation))
       ..fileSystem = fileSystem
       ..omitPlatform = true
-      ..environmentDefines = environmentDefines
+      ..environmentDefines = {
+        if (environmentDefines != null) ...environmentDefines,
+        // TODO(47243) Remove when all code paths read these from the `Target`.
+        ...sdkLibraryEnvironmentDefines
+      }
       ..explicitExperimentalFlags = explicitExperimentalFlags
       ..onDiagnostic = _onDiagnosticHandler(errors, warnings, infos)
       ..nnbdMode = soundNullSafety ? NnbdMode.Strong : NnbdMode.Weak

pkg/dev_compiler/lib/src/kernel/target.dart

@@ -19,6 +19,35 @@ import 'package:kernel/transformations/track_widget_constructor_locations.dart';
 import 'constants.dart' show DevCompilerConstantsBackend;
 import 'kernel_helpers.dart';
 
+/// Boolean environment variables that indicate which libraries are available in
+/// dev compiler.
+// TODO(jmesserly): provide an option to compile without dart:html & friends?
+const sdkLibraryEnvironmentDefines = {
+  'dart.isVM': 'false',
+  'dart.library.async': 'true',
+  'dart.library.core': 'true',
+  'dart.library.collection': 'true',
+  'dart.library.convert': 'true',
+  // TODO(jmesserly): this is not really supported in dart4web other than
+  // `debugger()`
+  'dart.library.developer': 'true',
+  'dart.library.io': 'false',
+  'dart.library.isolate': 'false',
+  'dart.library.js': 'true',
+  'dart.library.js_util': 'true',
+  'dart.library.math': 'true',
+  'dart.library.mirrors': 'false',
+  'dart.library.typed_data': 'true',
+  'dart.library.indexed_db': 'true',
+  'dart.library.html': 'true',
+  'dart.library.html_common': 'true',
+  'dart.library.svg': 'true',
+  'dart.library.ui': 'false',
+  'dart.library.web_audio': 'true',
+  'dart.library.web_gl': 'true',
+  'dart.library.web_sql': 'true',
+};
+
 /// A kernel [Target] to configure the Dart Front End for dartdevc.
 class DevCompilerTarget extends Target {
   DevCompilerTarget(this.flags);
@@ -30,6 +59,10 @@ class DevCompilerTarget extends Target {
 
   Map<String, Class>? _nativeClasses;
 
+  @override
+  Map<String, String> updateEnvironmentDefines(Map<String, String> map) =>
+      map..addAll(sdkLibraryEnvironmentDefines);
+
   @override
   bool get enableSuperMixins => true;
 

pkg/dev_compiler/test/expression_compiler/expression_compiler_worker_shared.dart

@@ -175,6 +175,40 @@ void runExpressionCompilationTests(TestDriver driver) {
           ]));
     });
 
+    test('compile expressions include "dart.library..." environment defines.',
+        () async {
+      driver.requestController.add({
+        'command': 'UpdateDeps',
+        'inputs': driver.inputs,
+      });
+
+      driver.requestController.add({
+        'command': 'CompileExpression',
+        'expression': 'const bool.fromEnvironment("dart.library.html")',
+        'line': 5,
+        'column': 1,
+        'jsModules': {},
+        'jsScope': {'formal': 'formal'},
+        'libraryUri': driver.config.testModule.libraryUri,
+        'moduleName': driver.config.testModule.moduleName,
+      });
+
+      expect(
+          driver.responseController.stream,
+          emitsInOrder([
+            equals({
+              'succeeded': true,
+            }),
+            equals({
+              'succeeded': true,
+              'errors': isEmpty,
+              'warnings': isEmpty,
+              'infos': isEmpty,
+              'compiledProcedure': contains('true'),
+            })
+          ]));
+    });
+
     test('can compile expressions in main', () async {
       driver.requestController.add({
         'command': 'UpdateDeps',

pkg/frontend_server/test/frontend_server_test.dart

@@ -2327,6 +2327,116 @@ class BarState extends State<FizzWidget> {
       expect(count, 3);
     });
 
+    test('compiled Javascript includes web library environment defines',
+        () async {
+      var file = File('${tempDir.path}/foo.dart')..createSync();
+      file.writeAsStringSync(
+          "main() {print(const bool.fromEnvironment('dart.library.html'));}\n");
+      var package_config =
+          File('${tempDir.path}/.dart_tool/package_config.json')
+            ..createSync(recursive: true)
+            ..writeAsStringSync('''
+  {
+    "configVersion": 2,
+    "packages": [
+      {
+        "name": "hello",
+        "rootUri": "../",
+        "packageUri": "./"
+      }
+    ]
+  }
+  ''');
+
+      var library = 'package:hello/foo.dart';
+      var module = 'packages/hello/foo.dart';
+
+      var dillFile = File('${tempDir.path}/foo.dart.dill');
+      var sourceFile = File('${dillFile.path}.sources');
+      var manifestFile = File('${dillFile.path}.json');
+      var sourceMapsFile = File('${dillFile.path}.map');
+
+      expect(dillFile.existsSync(), false);
+
+      final List<String> args = <String>[
+        '--sdk-root=${sdkRoot.toFilePath()}',
+        '--incremental',
+        '--platform=${ddcPlatformKernel.path}',
+        '--output-dill=${dillFile.path}',
+        '--target=dartdevc',
+        '--packages=${package_config.path}',
+      ];
+
+      final StreamController<List<int>> streamController =
+          StreamController<List<int>>();
+      final StreamController<List<int>> stdoutStreamController =
+          StreamController<List<int>>();
+      final IOSink ioSink = IOSink(stdoutStreamController.sink);
+      StreamController<Result> receivedResults = StreamController<Result>();
+      final outputParser = OutputParser(receivedResults);
+      stdoutStreamController.stream
+          .transform(utf8.decoder)
+          .transform(const LineSplitter())
+          .listen(outputParser.listener);
+
+      Future<int> result =
+          starter(args, input: streamController.stream, output: ioSink);
+      streamController.add('compile $library\n'.codeUnits);
+      int count = 0;
+      receivedResults.stream.listen((Result compiledResult) {
+        CompilationResult result =
+            CompilationResult.parse(compiledResult.status);
+        if (count == 0) {
+          // Request to 'compile', which results in full JavaScript.
+          expect(result.errorsCount, equals(0));
+          expect(sourceFile.existsSync(), equals(true));
+          expect(manifestFile.existsSync(), equals(true));
+          expect(sourceMapsFile.existsSync(), equals(true));
+          expect(result.filename, dillFile.path);
+
+          var compiledOutput = sourceFile.readAsStringSync();
+          // The constant environment variable should be inlined as a boolean
+          // literal.
+          expect(compiledOutput, contains('print(true);'));
+
+          streamController.add('accept\n'.codeUnits);
+
+          // 'compile-expression-to-js <boundarykey>
+          // libraryUri
+          // line
+          // column
+          // jsModules (one k-v pair per line)
+          // ...
+          // <boundarykey>
+          // jsFrameValues (one k-v pair per line)
+          // ...
+          // <boundarykey>
+          // moduleName
+          // expression
+          outputParser.expectSources = false;
+          streamController.add('compile-expression-to-js abc\n'
+                  '$library\n2\n1\nabc\nabc\n$module\n'
+                  'const bool.fromEnvironment("dart.library.html")\n'
+              .codeUnits);
+          count += 1;
+        } else {
+          expect(count, 1);
+          // Second request is to 'compile-expression-to-js' that should
+          // result in a literal `true` .
+          expect(result.errorsCount, 0);
+          var resultFile = File(result.filename);
+          // The constant environment variable should be inlined as a boolean
+          // literal.
+          expect(resultFile.readAsStringSync(), contains('return true;'));
+          outputParser.expectSources = false;
+          count += 1;
+          streamController.add('quit\n'.codeUnits);
+        }
+      });
+      expect(await result, 0);
+      expect(count, 2);
+    });
+
     test('mixed compile expression commands with web target', () async {
       var file = File('${tempDir.path}/foo.dart')..createSync();
       file.writeAsStringSync("main() {\n\n}\n");