Set dart defines properly while in debug mode. (#152262)

Turns out just supporting the right value for `kDebugMode` was a lot simpler than I thought. Debug builds used to never go through the build system code path when using `flutter run`, but now that we have wasm this can occur with the run command.

This should address https://github.com/flutter/flutter/issues/148850

dev/bots/suite_runners/run_web_tests.dart

@@ -224,6 +224,8 @@ class WebTestsSuite {
           '--dart-define=test.valueB=Value',
         ]
       ),
+      () => _runWebDebugTest('lib/assertion_test.dart'),
+      () => _runWebReleaseTest('lib/assertion_test.dart'),
       () => _runWebDebugTest('lib/sound_mode.dart'),
       () => _runWebReleaseTest('lib/sound_mode.dart'),
       () => _runFlutterWebTest(

dev/integration_tests/web/lib/assertion_test.dart

@@ -0,0 +1,32 @@
+// 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 'dart:js_interop';
+
+import 'package:flutter/foundation.dart';
+import 'package:web/web.dart' as web;
+
+Future<void> main() async  {
+  bool executedAssert = false;
+  assert(() {
+    executedAssert = true;
+    return true;
+  }());
+
+  final StringBuffer output = StringBuffer();
+  if (executedAssert == kDebugMode) {
+    output.write('--- TEST SUCCEEDED ---');
+  } else {
+    output.write('--- TEST FAILED ---');
+  }
+
+  await web.window.fetch(
+    '/test-result'.toJS,
+    web.RequestInit(
+      method: 'POST',
+      body: '$output'.toJS,
+    )
+  ).toDart;
+  print(output);
+}

packages/flutter_tools/lib/src/build_system/targets/web.dart

@@ -177,7 +177,7 @@ class Dart2JSTarget extends Dart2WebTarget {
       ...decodeCommaSeparated(environment.defines, kExtraFrontEndOptions),
       if (buildMode == BuildMode.profile)
         '-Ddart.vm.profile=true'
-      else
+      else if (buildMode == BuildMode.release)
         '-Ddart.vm.product=true',
       for (final String dartDefine in computeDartDefines(environment))
         '-D$dartDefine',
@@ -185,7 +185,7 @@ class Dart2JSTarget extends Dart2WebTarget {
 
     final List<String> compilationArgs = <String>[
       ...sharedCommandOptions,
-      ...compilerConfig.toSharedCommandOptions(),
+      ...compilerConfig.toSharedCommandOptions(buildMode),
       '-o',
       environment.buildDir.childFile('app.dill').path,
       '--packages=.dart_tool/package_config.json',
@@ -298,7 +298,6 @@ class Dart2WasmTarget extends Dart2WebTarget {
     final String platformBinariesPath = artifacts.getHostArtifact(HostArtifact.webPlatformKernelFolder).path;
     final String platformFilePath = environment.fileSystem.path.join(platformBinariesPath, 'dart2wasm_platform.dill');
 
-    assert(buildMode == BuildMode.release || buildMode == BuildMode.profile);
     final List<String> compilationArgs = <String>[
       artifacts.getArtifactPath(Artifact.engineDartBinary, platform: TargetPlatform.web_javascript),
       'compile',
@@ -313,7 +312,7 @@ class Dart2WasmTarget extends Dart2WebTarget {
       ],
       if (buildMode == BuildMode.profile)
         '-Ddart.vm.profile=true'
-      else
+      else if (buildMode == BuildMode.release)
         '-Ddart.vm.product=true',
       ...decodeCommaSeparated(environment.defines, kExtraFrontEndOptions),
       for (final String dartDefine in computeDartDefines(environment))

packages/flutter_tools/lib/src/web/compiler_config.dart

@@ -102,17 +102,18 @@ class JsCompilerConfig extends WebCompilerConfig {
   CompileTarget get compileTarget => CompileTarget.js;
 
   /// Arguments to use in both phases: full JS compile and CFE-only.
-  List<String> toSharedCommandOptions() => <String>[
+  List<String> toSharedCommandOptions(BuildMode buildMode) => <String>[
         if (nativeNullAssertions) '--native-null-assertions',
         if (!sourceMaps) '--no-source-maps',
+        if (buildMode == BuildMode.debug) '--enable-asserts',
       ];
 
   /// Arguments to use in the full JS compile, but not CFE-only.
   ///
   /// Includes the contents of [toSharedCommandOptions].
   List<String> toCommandOptions(BuildMode buildMode) => <String>[
-        if (buildMode == BuildMode.profile) '--no-minify',
-        ...toSharedCommandOptions(),
+        if (buildMode != BuildMode.release) '--no-minify',
+        ...toSharedCommandOptions(buildMode),
         '-O$optimizationLevel',
         if (dumpInfo) '--dump-info',
         if (noFrequencyBasedMinification) '--no-frequency-based-minification',
@@ -157,6 +158,7 @@ class WasmCompilerConfig extends WebCompilerConfig {
       '-O$optimizationLevel',
       '--${stripSymbols ? '' : 'no-'}strip-wasm',
       if (!sourceMaps) '--extra-compiler-option=--no-source-maps',
+      if (buildMode == BuildMode.debug) '--extra-compiler-option=--enable-asserts',
     ];
   }
 

packages/flutter_tools/test/general.shard/build_system/targets/web_test.dart

@@ -868,6 +868,54 @@ void main() {
     ProcessManager: () => processManager,
   }));
 
+  test('Dart2JSTarget calls dart2js with Dart defines in debug mode', () => testbed.run(() async {
+    environment.defines[kBuildMode] = 'debug';
+    environment.defines[kDartDefines] = encodeDartDefines(<String>['FOO=bar', 'BAZ=qux']);
+    processManager.addCommand(FakeCommand(
+      command: <String>[
+        ..._kDart2jsLinuxArgs,
+        '-DFOO=bar',
+        '-DBAZ=qux',
+        '-DFLUTTER_WEB_AUTO_DETECT=false',
+        '-DFLUTTER_WEB_USE_SKIA=true',
+        '-DFLUTTER_WEB_CANVASKIT_URL=https://www.gstatic.com/flutter-canvaskit/abcdefghijklmnopqrstuvwxyz/',
+        '--no-source-maps',
+        '--enable-asserts',
+        '-o',
+        environment.buildDir.childFile('app.dill').absolute.path,
+        '--packages=.dart_tool/package_config.json',
+        '--cfe-only',
+        environment.buildDir.childFile('main.dart').absolute.path,
+      ]
+    ));
+    processManager.addCommand(FakeCommand(
+      command: <String>[
+        ..._kDart2jsLinuxArgs,
+        '-DFOO=bar',
+        '-DBAZ=qux',
+        '-DFLUTTER_WEB_AUTO_DETECT=false',
+        '-DFLUTTER_WEB_USE_SKIA=true',
+        '-DFLUTTER_WEB_CANVASKIT_URL=https://www.gstatic.com/flutter-canvaskit/abcdefghijklmnopqrstuvwxyz/',
+        '--no-minify',
+        '--no-source-maps',
+        '--enable-asserts',
+        '-O4',
+        '-o',
+        environment.buildDir.childFile('main.dart.js').absolute.path,
+        environment.buildDir.childFile('app.dill').absolute.path,
+      ]
+    ));
+
+    await Dart2JSTarget(
+      const JsCompilerConfig(
+        sourceMaps: false,
+      )
+    ).build(environment);
+  }, overrides: <Type, Generator>{
+    ProcessManager: () => processManager,
+  }));
+
+
   test('Dart2JSTarget calls dart2js with expected args with dump-info', () => testbed.run(() async {
     environment.defines[kBuildMode] = 'profile';
     environment.defines[JsCompilerConfig.kDart2jsDumpInfo] = 'true';
@@ -962,7 +1010,7 @@ void main() {
     for (int level = 1; level <= 4; level++) {
       for (final bool strip in <bool>[true, false]) {
         for (final List<String> defines in const <List<String>>[<String>[], <String>['FOO=bar', 'BAZ=qux']]) {
-          for (final String buildMode in const <String>['profile', 'release']) {
+          for (final String buildMode in const <String>['profile', 'release', 'debug']) {
             for (final bool sourceMaps in const <bool>[true, false]) {
               test('Dart2WasmTarget invokes dart2wasm with renderer=$renderer, -O$level, stripping=$strip, defines=$defines, modeMode=$buildMode sourceMaps=$sourceMaps', () => testbed.run(() async {
                 environment.defines[kBuildMode] = buildMode;
@@ -978,7 +1026,8 @@ void main() {
                       '--extra-compiler-option=--import-shared-memory',
                       '--extra-compiler-option=--shared-memory-max-pages=32768',
                     ],
-                    '-Ddart.vm.${buildMode == 'release' ? 'product' : 'profile' }=true',
+                    if (buildMode != 'debug')
+                      '-Ddart.vm.${buildMode == 'release' ? 'product' : 'profile' }=true',
                     ...defines.map((String define) => '-D$define'),
                     if (renderer == WebRendererMode.skwasm) ...<String>[
                       '-DFLUTTER_WEB_AUTO_DETECT=false',
@@ -994,6 +1043,7 @@ void main() {
                     '-O$level',
                     if (strip && buildMode == 'release') '--strip-wasm' else '--no-strip-wasm',
                     if (!sourceMaps) '--extra-compiler-option=--no-source-maps',
+                    if (buildMode == 'debug') '--extra-compiler-option=--enable-asserts',
                     '-o',
                     environment.buildDir.childFile('main.dart.wasm').absolute.path,
                     environment.buildDir.childFile('main.dart').absolute.path,