Enable weak tests for build daemon and frontend server

dwds/test/fixtures/context.dart

@@ -229,6 +229,7 @@ class TestContext {
       String basePath = '';
 
       _port = await findUnusedPort();
+      final soundNullSafety = nullSafety == NullSafety.sound;
       switch (compilationMode) {
         case CompilationMode.buildDaemon:
           {
@@ -237,6 +238,8 @@ class TestContext {
                 '--define',
                 'build_web_compilers|ddc=generate-full-dill=true',
               ],
+              '--define',
+              'build_web_compilers:entrypoint=sound_null_safety=$soundNullSafety',
               '--verbose',
             ];
             _daemonClient =

dwds/test/utils/version_compatibility.dart

@@ -2,21 +2,11 @@
 // 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.
 
-import 'dart:io';
-
-import 'package:pub_semver/pub_semver.dart';
-
 import '../fixtures/context.dart';
 
 bool supportedMode(
     {required CompilationMode compilationMode,
     required NullSafety nullSafetyMode}) {
-  final isDart3 = Version.parse(Platform.version.split(' ')[0]).major == 3;
-  // TODO(https://github.com/dart-lang/webdev/issues/1818): Support compiling to
-  // to weak null-safety for both FrontendServer and BuildDaemon.
-  if (isDart3 && nullSafetyMode == NullSafety.weak) {
-    return false;
-  }
   // TODO(https://github.com/dart-lang/webdev/issues/1591): Support compiling to
   // sound null-safety for the FrontendServer.
   if (compilationMode == CompilationMode.frontendServer &&

fixtures/_test/example/append_body/main.dart

@@ -2,6 +2,8 @@
 // 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.
 
+// @dart=2.9
+
 import 'dart:async';
 import 'dart:developer';
 import 'dart:html';

fixtures/_test/example/hello_world/main.dart

@@ -2,6 +2,8 @@
 // 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.
 
+// @dart=2.9
+
 import 'dart:async';
 import 'dart:convert';
 import 'dart:developer';

fixtures/_test/example/hello_world/part.dart

@@ -2,6 +2,8 @@
 // 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.
 
+// @dart=2.9
+
 part of 'main.dart';
 
 var blah = 'blah';

fixtures/_test/pubspec.yaml

@@ -9,12 +9,12 @@ description: >-
 publish_to: none
 
 environment:
-  sdk: ">=2.5.0 <3.0.0"
+  sdk: ">=2.18.0 <3.0.0"
 
 dependencies:
-  intl: ^0.16.0
+  intl: ^0.17.0
   path: ^1.6.1
 
 dev_dependencies:
-  build_runner: ^2.0.0
-  build_web_compilers: ^3.0.0
+  build_runner: '>=1.6.2 <3.0.0'
+  build_web_compilers: '>=2.12.0 <4.0.0'

fixtures/_testCircular1/pubspec.yaml

@@ -5,14 +5,14 @@
 name: _test_circular1
 version: 1.0.0
 description: >-
-  A fake package used for testing weak null-safety.
+  A fake package used for testing weak null-safety with circular dependency.
 publish_to: none
 
 environment:
-  sdk: ">=2.5.0 <3.0.0"
+  sdk: ">=2.18.0 <3.0.0"
 
 dependencies:
-  intl: ^0.16.0
+  intl: ^0.17.0
   path: ^1.6.1
   _test_circular2:
     path: ../_testCircular2

fixtures/_testCircular1Sound/pubspec.yaml

@@ -1,11 +1,11 @@
 name: _test_circular1_sound
 version: 1.0.0
 description: >-
-  A fake package used for testing sound null-safety.
+    A fake package used for testing imports with sound null-safety with circular dependency.
 publish_to: none
 
 environment:
-  sdk: '>=2.12.0 <3.0.0'
+  sdk: '>=2.18.0 <3.0.0'
 
 dependencies:
   intl: ^0.17.0

fixtures/_testCircular2/pubspec.yaml

@@ -5,11 +5,11 @@
 name: _test_circular2
 version: 1.0.0
 description: >-
-  A fake package used for testing imports with weak null-safety. Imports _test.
+  A fake package used for testing imports with weak null-safety with circular dependency.
 publish_to: none
 
 environment:
-  sdk: ">=2.10.0 <3.0.0"
+  sdk: ">=2.18.0 <3.0.0"
 
 dependencies:
   _test_circular1:

fixtures/_testCircular2Sound/pubspec.yaml

@@ -1,11 +1,11 @@
 name: _test_circular2_sound
 version: 1.0.0
 description: >-
-  A fake package used for testing imports with sound null-safety. Imports _test.
+  A fake package used for testing imports with sound null-safety with circular dependency.
 publish_to: none
 
 environment:
-  sdk: '>=2.12.0 <3.0.0'
+  sdk: '>=2.18.0 <3.0.0'
 
 dependencies:
   _test_circular1_sound:

fixtures/_testPackage/pubspec.yaml

@@ -9,7 +9,7 @@ description: >-
 publish_to: none
 
 environment:
-  sdk: ">=2.10.0 <3.0.0"
+  sdk: ">=2.18.0 <3.0.0"
 
 dependencies:
   _test:

frontend_server_common/lib/src/frontend_server_client.dart

@@ -259,6 +259,7 @@ class ResidentCompiler {
     required this.fileSystemRoots,
     required this.fileSystemScheme,
     required this.platformDill,
+    required this.soundNullSafety,
     this.verbose = false,
     CompilerMessageConsumer compilerMessageConsumer = defaultConsumer,
   }) : _stdoutHandler = StdoutHandler(consumer: compilerMessageConsumer);
@@ -269,6 +270,7 @@ class ResidentCompiler {
   final List<Uri> fileSystemRoots;
   final String fileSystemScheme;
   final String platformDill;
+  final bool soundNullSafety;
   final bool verbose;
 
   /// The path to the root of the Dart SDK used to compile.
@@ -386,6 +388,8 @@ class ResidentCompiler {
       ],
       if (useDebuggerModuleNames) '--debugger-module-names',
       '--experimental-emit-debug-metadata',
+      if (soundNullSafety) '--sound-null-safety',
+      if (!soundNullSafety) '--no-sound-null-safety',
       if (verbose) '--verbose'
     ];
 

frontend_server_common/lib/src/resident_runner.dart

@@ -46,6 +46,7 @@ class ResidentWebRunner {
       fileSystemRoots: fileSystemRoots,
       fileSystemScheme: fileSystemScheme,
       verbose: verbose,
+      soundNullSafety: soundNullSafety,
     );
     expressionCompiler = TestExpressionCompiler(generator);
   }

webdev/test/e2e_test.dart

@@ -302,6 +302,7 @@ void main() {
               'daemon',
               'web:$openPort',
               '--enable-expression-evaluation',
+              '--null-safety=$nullSafetyOption',
               '--verbose',
             ];
             var process = await runWebDev(args,