Support dart2wasm in node.js tests (#2259)

Support `dart2wasm` as a compiler for tests running in Node.js.
`dart2wasm` emits a `.mjs` file exporting definitions to load generated
wasm modules, the only additional thing we have to do is wrap that in a
simple entrypoint file compiling the wasm module and invoking the
startup wrapper.

There's no support for stack trace maps yet. We also don't support
precompiled node wasm tests yet (`dart2wasm` is also not currently
supported by `build_web_compilers`, so we're blocked on that either
way).

In the test runtime, I had to migrate off `require` as that function is
not in the global context for `.mjs` files. It looks like we can use
`await import` instead though. If we need to support ancient Node
versions that lack `import` support, I can adapt that to still use
`require` when compiled with `dart2js` for compatibility.

Author: simolus3

.github/workflows/dart.yml

@@ -1,7 +1,7 @@
 name: regression_tests
 publish_to: none
 environment:
-  sdk: ^3.5.0-259.0.dev
+  sdk: ^3.5.0-311.0.dev
 resolution: workspace
 dependencies:
   test: any

integration_tests/regression/pubspec.yaml

@@ -1,7 +1,7 @@
 name: spawn_hybrid
 publish_to: none
 environment:
-  sdk: ^3.5.0-259.0.dev
+  sdk: ^3.5.0-311.0.dev
 resolution: workspace
 dependencies:
   async: ^2.9.0

integration_tests/spawn_hybrid/pubspec.yaml

@@ -1,2 +1,5 @@
 platforms: [chrome, firefox]
+# Node doesn't work because the version available in the current Ubuntu GitHub runners is too
+# old to support WASM+GC, which would be required to run Dart tests.
+#platforms: [chrome, firefox, node]
 compilers: [dart2wasm]

integration_tests/wasm/dart_test.yaml

@@ -1,7 +1,7 @@
 name: wasm_tests
 publish_to: none
 environment:
-  sdk: ^3.5.0-259.0.dev
+  sdk: ^3.5.0-311.0.dev
 resolution: workspace
 dev_dependencies:
   test: any

integration_tests/wasm/pubspec.yaml

@@ -7,7 +7,7 @@ repository: https://github.com/dart-lang/test/tree/master/pkgs/checks
 resolution: workspace
 
 environment:
-  sdk: ^3.5.0-259.0.dev
+  sdk: ^3.5.0-311.0.dev
 
 dependencies:
   async: ^2.8.0

pkgs/checks/pubspec.yaml

@@ -1,7 +1,8 @@
 ## 1.25.9-wip
 
 * Fix dart2wasm tests on windows.
-* Increase SDK constraint to ^3.5.0-259.0.dev.
+* Increase SDK constraint to ^3.5.0-311.0.dev.
+* Support running Node.js tests compiled with dart2wasm.
 
 ## 1.25.8
 

pkgs/test/CHANGELOG.md

@@ -14,5 +14,5 @@ void internalBootstrapNodeTest(Function Function() getMain) {
     if (serialized is! Map) return;
     setStackTraceMapper(JSStackTraceMapper.deserialize(serialized)!);
   });
-  socketChannel().pipe(channel);
+  socketChannel().then((socket) => socket.pipe(channel));
 }

pkgs/test/lib/src/bootstrap/node.dart

@@ -16,17 +16,18 @@ import 'package:test_api/backend.dart'
 import 'package:test_core/src/runner/application_exception.dart'; // ignore: implementation_imports
 import 'package:test_core/src/runner/configuration.dart'; // ignore: implementation_imports
 import 'package:test_core/src/runner/dart2js_compiler_pool.dart'; // ignore: implementation_imports
+import 'package:test_core/src/runner/load_exception.dart'; // ignore: implementation_imports
 import 'package:test_core/src/runner/package_version.dart'; // ignore: implementation_imports
 import 'package:test_core/src/runner/platform.dart'; // ignore: implementation_imports
 import 'package:test_core/src/runner/plugin/customizable_platform.dart'; // ignore: implementation_imports
 import 'package:test_core/src/runner/plugin/environment.dart'; // ignore: implementation_imports
 import 'package:test_core/src/runner/plugin/platform_helpers.dart'; // ignore: implementation_imports
 import 'package:test_core/src/runner/runner_suite.dart'; // ignore: implementation_imports
 import 'package:test_core/src/runner/suite.dart'; // ignore: implementation_imports
+import 'package:test_core/src/runner/wasm_compiler_pool.dart'; // ignore: implementation_imports
 import 'package:test_core/src/util/errors.dart'; // ignore: implementation_imports
 import 'package:test_core/src/util/io.dart'; // ignore: implementation_imports
 import 'package:test_core/src/util/package_config.dart'; // ignore: implementation_imports
-import 'package:test_core/src/util/pair.dart'; // ignore: implementation_imports
 import 'package:test_core/src/util/stack_trace_mapper.dart'; // ignore: implementation_imports
 import 'package:yaml/yaml.dart';
 
@@ -40,7 +41,8 @@ class NodePlatform extends PlatformPlugin
   final Configuration _config;
 
   /// The [Dart2JsCompilerPool] managing active instances of `dart2js`.
-  final _compilers = Dart2JsCompilerPool(['-Dnode=true', '--server-mode']);
+  final _jsCompilers = Dart2JsCompilerPool(['-Dnode=true', '--server-mode']);
+  final _wasmCompilers = WasmCompilerPool(['-Dnode=true']);
 
   /// The temporary directory in which compiled JS is emitted.
   final _compiledDir = createTempDir();
@@ -75,15 +77,17 @@ class NodePlatform extends PlatformPlugin
   @override
   Future<RunnerSuite> load(String path, SuitePlatform platform,
       SuiteConfiguration suiteConfig, Map<String, Object?> message) async {
-    if (platform.compiler != Compiler.dart2js) {
+    if (platform.compiler != Compiler.dart2js &&
+        platform.compiler != Compiler.dart2wasm) {
       throw StateError(
           'Unsupported compiler for the Node platform ${platform.compiler}.');
     }
-    var pair = await _loadChannel(path, platform, suiteConfig);
+    var (channel, stackMapper) =
+        await _loadChannel(path, platform, suiteConfig);
     var controller = deserializeSuite(path, platform, suiteConfig,
-        const PluginEnvironment(), pair.first, message);
+        const PluginEnvironment(), channel, message);
 
-    controller.channel('test.node.mapper').sink.add(pair.last?.serialize());
+    controller.channel('test.node.mapper').sink.add(stackMapper?.serialize());
 
     return await controller.suite;
   }
@@ -92,16 +96,13 @@ class NodePlatform extends PlatformPlugin
   ///
   /// Returns that channel along with a [StackTraceMapper] representing the
   /// source map for the compiled suite.
-  Future<Pair<StreamChannel<Object?>, StackTraceMapper?>> _loadChannel(
-      String path,
-      SuitePlatform platform,
-      SuiteConfiguration suiteConfig) async {
+  Future<(StreamChannel<Object?>, StackTraceMapper?)> _loadChannel(String path,
+      SuitePlatform platform, SuiteConfiguration suiteConfig) async {
     final servers = await _loopback();
 
     try {
-      var pair = await _spawnProcess(
-          path, platform.runtime, suiteConfig, servers.first.port);
-      var process = pair.first;
+      var (process, stackMapper) =
+          await _spawnProcess(path, platform, suiteConfig, servers.first.port);
 
       // Forward Node's standard IO to the print handler so it's associated with
       // the load test.
@@ -110,7 +111,19 @@ class NodePlatform extends PlatformPlugin
       process.stdout.transform(lineSplitter).listen(print);
       process.stderr.transform(lineSplitter).listen(print);
 
-      var socket = await StreamGroup.merge(servers).first;
+      // Wait for the first connection (either over ipv4 or v6). If the proccess
+      // exits before it connects, throw instead of waiting for a connection
+      // indefinitely.
+      var socket = await Future.any([
+        StreamGroup.merge(servers).first,
+        process.exitCode.then((_) => null),
+      ]);
+
+      if (socket == null) {
+        throw LoadException(
+            path, 'Node exited before connecting to the test channel.');
+      }
+
       var channel = StreamChannel(socket.cast<List<int>>(), socket)
           .transform(StreamChannelTransformer.fromCodec(utf8))
           .transform(_chunksToLines)
@@ -120,7 +133,7 @@ class NodePlatform extends PlatformPlugin
         sink.close();
       }));
 
-      return Pair(channel, pair.last);
+      return (channel, stackMapper);
     } finally {
       unawaited(Future.wait<void>(servers.map((s) =>
           s.close().then<ServerSocket?>((v) => v).onError((_, __) => null))));
@@ -131,23 +144,28 @@ class NodePlatform extends PlatformPlugin
   ///
   /// Returns that channel along with a [StackTraceMapper] representing the
   /// source map for the compiled suite.
-  Future<Pair<Process, StackTraceMapper?>> _spawnProcess(String path,
-      Runtime runtime, SuiteConfiguration suiteConfig, int socketPort) async {
+  Future<(Process, StackTraceMapper?)> _spawnProcess(
+      String path,
+      SuitePlatform platform,
+      SuiteConfiguration suiteConfig,
+      int socketPort) async {
     if (_config.suiteDefaults.precompiledPath != null) {
-      return _spawnPrecompiledProcess(path, runtime, suiteConfig, socketPort,
-          _config.suiteDefaults.precompiledPath!);
+      return _spawnPrecompiledProcess(path, platform.runtime, suiteConfig,
+          socketPort, _config.suiteDefaults.precompiledPath!);
     } else {
-      return _spawnNormalProcess(path, runtime, suiteConfig, socketPort);
+      return switch (platform.compiler) {
+        Compiler.dart2js => _spawnNormalJsProcess(
+            path, platform.runtime, suiteConfig, socketPort),
+        Compiler.dart2wasm => _spawnNormalWasmProcess(
+            path, platform.runtime, suiteConfig, socketPort),
+        _ => throw StateError('Unsupported compiler ${platform.compiler}'),
+      };
     }
   }
 
-  /// Compiles [testPath] with dart2js, adds the node preamble, and then spawns
-  /// a Node.js process that loads that Dart test suite.
-  Future<Pair<Process, StackTraceMapper?>> _spawnNormalProcess(String testPath,
-      Runtime runtime, SuiteConfiguration suiteConfig, int socketPort) async {
-    var dir = Directory(_compiledDir).createTempSync('test_').path;
-    var jsPath = p.join(dir, '${p.basename(testPath)}.node_test.dart.js');
-    await _compilers.compile('''
+  Future<String> _entrypointScriptForTest(
+      String testPath, SuiteConfiguration suiteConfig) async {
+    return '''
         ${suiteConfig.metadata.languageVersionComment ?? await rootPackageLanguageVersionComment}
         import "package:test/src/bootstrap/node.dart";
 
@@ -156,7 +174,20 @@ class NodePlatform extends PlatformPlugin
         void main() {
           internalBootstrapNodeTest(() => test.main);
         }
-      ''', jsPath, suiteConfig);
+      ''';
+  }
+
+  /// Compiles [testPath] with dart2js, adds the node preamble, and then spawns
+  /// a Node.js process that loads that Dart test suite.
+  Future<(Process, StackTraceMapper?)> _spawnNormalJsProcess(String testPath,
+      Runtime runtime, SuiteConfiguration suiteConfig, int socketPort) async {
+    var dir = Directory(_compiledDir).createTempSync('test_').path;
+    var jsPath = p.join(dir, '${p.basename(testPath)}.node_test.dart.js');
+    await _jsCompilers.compile(
+      await _entrypointScriptForTest(testPath, suiteConfig),
+      jsPath,
+      suiteConfig,
+    );
 
     // Add the Node.js preamble to ensure that the dart2js output is
     // compatible. Use the minified version so the source map remains valid.
@@ -173,12 +204,63 @@ class NodePlatform extends PlatformPlugin
           packageMap: (await currentPackageConfig).toPackageMap());
     }
 
-    return Pair(await _startProcess(runtime, jsPath, socketPort), mapper);
+    return (await _startProcess(runtime, jsPath, socketPort), mapper);
+  }
+
+  /// Compiles [testPath] with dart2wasm, adds a JS entrypoint and then spawns
+  /// a Node.js process loading the compiled test suite.
+  Future<(Process, StackTraceMapper?)> _spawnNormalWasmProcess(String testPath,
+      Runtime runtime, SuiteConfiguration suiteConfig, int socketPort) async {
+    var dir = Directory(_compiledDir).createTempSync('test_').path;
+    // dart2wasm will emit a .wasm file and a .mjs file responsible for loading
+    // that file.
+    var wasmPath = p.join(dir, '${p.basename(testPath)}.node_test.dart.wasm');
+    var loader = '${p.basename(testPath)}.node_test.dart.wasm.mjs';
+
+    // We need to create an additional entrypoint file loading the wasm module.
+    var jsPath = p.join(dir, '${p.basename(testPath)}.node_test.dart.js');
+
+    await _wasmCompilers.compile(
+      await _entrypointScriptForTest(testPath, suiteConfig),
+      wasmPath,
+      suiteConfig,
+    );
+
+    await File(jsPath).writeAsString('''
+const { createReadStream } = require('fs');
+const { once } = require('events');
+const { PassThrough } = require('stream');
+
+const main = async () => {
+  const { instantiate, invoke } = await import("./$loader");
+
+  const wasmContents = createReadStream("$wasmPath.wasm");
+  const stream = new PassThrough();
+  wasmContents.pipe(stream);
+
+  await once(wasmContents, 'open');
+  const response = new Response(
+    stream,
+    {
+      headers: {
+        "Content-Type": "application/wasm"
+      }
+    }
+  );
+  const instancePromise = WebAssembly.compileStreaming(response);
+  const module = await instantiate(instancePromise, {});
+  invoke(module);
+};
+
+main();
+''');
+
+    return (await _startProcess(runtime, jsPath, socketPort), null);
   }
 
   /// Spawns a Node.js process that loads the Dart test suite at [testPath]
   /// under [precompiledPath].
-  Future<Pair<Process, StackTraceMapper?>> _spawnPrecompiledProcess(
+  Future<(Process, StackTraceMapper?)> _spawnPrecompiledProcess(
       String testPath,
       Runtime runtime,
       SuiteConfiguration suiteConfig,
@@ -195,7 +277,7 @@ class NodePlatform extends PlatformPlugin
               .toPackageMap());
     }
 
-    return Pair(await _startProcess(runtime, jsPath, socketPort), mapper);
+    return (await _startProcess(runtime, jsPath, socketPort), mapper);
   }
 
   /// Starts the Node.js process for [runtime] with [jsPath].
@@ -224,7 +306,8 @@ class NodePlatform extends PlatformPlugin
 
   @override
   Future<void> close() => _closeMemo.runOnce(() async {
-        await _compilers.close();
+        await _jsCompilers.close();
+        await _wasmCompilers.close();
         await Directory(_compiledDir).deleteWithRetry();
       });
   final _closeMemo = AsyncMemoizer<void>();

pkgs/test/lib/src/runner/node/platform.dart

@@ -1,46 +1,41 @@
 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
-
-@JS()
-library;
-
 import 'dart:async';
 import 'dart:convert';
+import 'dart:js_interop';
 
-import 'package:js/js.dart';
 import 'package:stream_channel/stream_channel.dart';
 
-@JS('require')
-external _Net _require(String module);
-
 @JS('process.argv')
-external List<String> get _args;
+external JSArray<JSString> get _args;
 
-@JS()
-class _Net {
+extension type _Net._(JSObject _) {
   external _Socket connect(int port);
 }
 
-@JS()
-class _Socket {
-  external void setEncoding(String encoding);
-  external void on(String event, void Function(String chunk) callback);
-  external void write(String data);
+extension type _Socket._(JSObject _) {
+  external void setEncoding(JSString encoding);
+  external void on(JSString event, JSFunction callback);
+  external void write(JSString data);
 }
 
 /// Returns a [StreamChannel] of JSON-encodable objects that communicates over a
 /// socket whose port is given by `process.argv[2]`.
-StreamChannel<Object?> socketChannel() {
-  var net = _require('net');
-  var socket = net.connect(int.parse(_args[2]));
-  socket.setEncoding('utf8');
+Future<StreamChannel<Object?>> socketChannel() async {
+  final net = (await importModule('node:net'.toJS).toDart) as _Net;
+
+  var socket = net.connect(int.parse(_args.toDart[2].toDart));
+  socket.setEncoding('utf8'.toJS);
 
   var socketSink = StreamController<Object?>(sync: true)
-    ..stream.listen((event) => socket.write('${jsonEncode(event)}\n'));
+    ..stream.listen((event) => socket.write('${jsonEncode(event)}\n'.toJS));
 
   var socketStream = StreamController<String>(sync: true);
-  socket.on('data', allowInterop(socketStream.add));
+  socket.on(
+    'data'.toJS,
+    ((JSString chunk) => socketStream.add(chunk.toDart)).toJS,
+  );
 
   return StreamChannel.withCloseGuarantee(
       socketStream.stream.transform(const LineSplitter()).map(jsonDecode),