Speed up native assets target (#134523)

Speeds up the native assets target in the backend by

1. changing other targets `gen_dart_plugin_registrant` and
`release_unpack_ios` to do async I/O,
2. not reparsing the package config, and
3. not calling `dart pub deps --json` for 0 or 1 packages (fixed
package:native_assets_builder).

* https://github.com/flutter/flutter/issues/134427

```
           [   +2 ms] native_assets: Starting due to {}
           [   +2 ms] Skipping target: gen_localizations
           [   +1 ms] gen_dart_plugin_registrant: Starting due to {InvalidatedReasonKind.inputChanged: The following inputs have updated contents: /Users/dacoharkes/flt/engine/flutter/examples/hello_world/.dart_tool/package_config_subset}
           [  +33 ms] gen_dart_plugin_registrant: Complete
           [ +107 ms] release_unpack_ios: Complete
           [  +60 ms] Writing native_assets.yaml.
           [   +7 ms] Writing /Users/dacoharkes/flt/engine/flutter/examples/hello_world/.dart_tool/flutter_build/be2692bbfbc0b9a27fcd2422d52354c6/native_assets.yaml done.
           [        ] native_assets: Complete
```

->

```
           [   +4 ms] native_assets: Starting due to {}
           [        ] Skipping target: gen_localizations
           [   +1 ms] gen_dart_plugin_registrant: Starting due to {InvalidatedReasonKind.inputChanged: The following inputs have updated contents: /Users/dacoharkes/flt/engine/flutter/examples/hello_world/.dart_tool/package_config_subset}
           [  +31 ms] Writing native_assets.yaml.
           [   +8 ms] Writing /Users/dacoharkes/flt/engine/flutter/examples/hello_world/.dart_tool/flutter_build/f9451a65a465bfab70d004e21d6cc1d6/native_assets.yaml done.
           [   +1 ms] native_assets: Complete
```

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [ ] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] All existing and new tests are passing.


<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#overview
[Tree Hygiene]: https://github.com/flutter/flutter/wiki/Tree-hygiene
[test-exempt]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/wiki/Tree-hygiene#handling-breaking-changes
[Discord]: https://github.com/flutter/flutter/wiki/Chat

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

@@ -287,21 +287,21 @@ abstract class UnpackIOS extends Target {
     if (archs == null) {
       throw MissingDefineException(kIosArchs, name);
     }
-    _copyFramework(environment, sdkRoot);
+    await _copyFramework(environment, sdkRoot);
 
     final File frameworkBinary = environment.outputDir.childDirectory('Flutter.framework').childFile('Flutter');
     final String frameworkBinaryPath = frameworkBinary.path;
-    if (!frameworkBinary.existsSync()) {
+    if (!await frameworkBinary.exists()) {
       throw Exception('Binary $frameworkBinaryPath does not exist, cannot thin');
     }
-    _thinFramework(environment, frameworkBinaryPath, archs);
+    await _thinFramework(environment, frameworkBinaryPath, archs);
     if (buildMode == BuildMode.release) {
-      _bitcodeStripFramework(environment, frameworkBinaryPath);
+      await _bitcodeStripFramework(environment, frameworkBinaryPath);
     }
     await _signFramework(environment, frameworkBinary, buildMode);
   }
 
-  void _copyFramework(Environment environment, String sdkRoot) {
+  Future<void> _copyFramework(Environment environment, String sdkRoot) async {
     final EnvironmentType? environmentType = environmentTypeFromSdkroot(sdkRoot, environment.fileSystem);
     final String basePath = environment.artifacts.getArtifactPath(
       Artifact.flutterFramework,
@@ -310,7 +310,7 @@ abstract class UnpackIOS extends Target {
       environmentType: environmentType,
     );
 
-    final ProcessResult result = environment.processManager.runSync(<String>[
+    final ProcessResult result = await environment.processManager.run(<String>[
       'rsync',
       '-av',
       '--delete',
@@ -328,16 +328,20 @@ abstract class UnpackIOS extends Target {
   }
 
   /// Destructively thin Flutter.framework to include only the specified architectures.
-  void _thinFramework(Environment environment, String frameworkBinaryPath, String archs) {
+  Future<void> _thinFramework(
+    Environment environment,
+    String frameworkBinaryPath,
+    String archs,
+  ) async {
     final List<String> archList = archs.split(' ').toList();
-    final ProcessResult infoResult = environment.processManager.runSync(<String>[
+    final ProcessResult infoResult = await environment.processManager.run(<String>[
       'lipo',
       '-info',
       frameworkBinaryPath,
     ]);
     final String lipoInfo = infoResult.stdout as String;
 
-    final ProcessResult verifyResult = environment.processManager.runSync(<String>[
+    final ProcessResult verifyResult = await environment.processManager.run(<String>[
       'lipo',
       frameworkBinaryPath,
       '-verify_arch',
@@ -355,7 +359,7 @@ abstract class UnpackIOS extends Target {
     }
 
     // Thin in-place.
-    final ProcessResult extractResult = environment.processManager.runSync(<String>[
+    final ProcessResult extractResult = await environment.processManager.run(<String>[
       'lipo',
       '-output',
       frameworkBinaryPath,
@@ -374,8 +378,11 @@ abstract class UnpackIOS extends Target {
 
   /// Destructively strip bitcode from the framework. This can be removed
   /// when the framework is no longer built with bitcode.
-  void _bitcodeStripFramework(Environment environment, String frameworkBinaryPath) {
-    final ProcessResult stripResult = environment.processManager.runSync(<String>[
+  Future<void> _bitcodeStripFramework(
+    Environment environment,
+    String frameworkBinaryPath,
+  ) async {
+    final ProcessResult stripResult = await environment.processManager.run(<String>[
       'xcrun',
       'bitcode_strip',
       frameworkBinaryPath,

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

@@ -80,7 +80,7 @@ abstract class UnpackMacOS extends Target {
     if (!frameworkBinary.existsSync()) {
       throw Exception('Binary $frameworkBinaryPath does not exist, cannot thin');
     }
-    _thinFramework(environment, frameworkBinaryPath);
+    await _thinFramework(environment, frameworkBinaryPath);
   }
 
   static const List<String> _copyDenylist = <String>['entitlements.txt', 'without_entitlements.txt'];
@@ -96,17 +96,21 @@ abstract class UnpackMacOS extends Target {
     }
   }
 
-  void _thinFramework(Environment environment, String frameworkBinaryPath) {
+  Future<void> _thinFramework(
+    Environment environment,
+    String frameworkBinaryPath,
+  ) async {
     final String archs = environment.defines[kDarwinArchs] ?? 'x86_64 arm64';
     final List<String> archList = archs.split(' ').toList();
-    final ProcessResult infoResult = environment.processManager.runSync(<String>[
+    final ProcessResult infoResult =
+        await environment.processManager.run(<String>[
       'lipo',
       '-info',
       frameworkBinaryPath,
     ]);
     final String lipoInfo = infoResult.stdout as String;
 
-    final ProcessResult verifyResult = environment.processManager.runSync(<String>[
+    final ProcessResult verifyResult = await environment.processManager.run(<String>[
       'lipo',
       frameworkBinaryPath,
       '-verify_arch',

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

@@ -4,11 +4,13 @@
 
 import 'package:meta/meta.dart';
 import 'package:native_assets_cli/native_assets_cli.dart' show Asset;
+import 'package:package_config/package_config_types.dart';
 
 import '../../base/common.dart';
 import '../../base/file_system.dart';
 import '../../base/platform.dart';
 import '../../build_info.dart';
+import '../../dart/package_map.dart';
 import '../../ios/native_assets.dart';
 import '../../macos/native_assets.dart';
 import '../../macos/xcode.dart';
@@ -52,7 +54,21 @@ class NativeAssets extends Target {
 
     final Uri projectUri = environment.projectDir.uri;
     final FileSystem fileSystem = environment.fileSystem;
-    final NativeAssetsBuildRunner buildRunner = _buildRunner ?? NativeAssetsBuildRunnerImpl(projectUri, fileSystem, environment.logger);
+    final File packagesFile = fileSystem
+        .directory(projectUri)
+        .childDirectory('.dart_tool')
+        .childFile('package_config.json');
+    final PackageConfig packageConfig = await loadPackageConfigWithLogging(
+      packagesFile,
+      logger: environment.logger,
+    );
+    final NativeAssetsBuildRunner buildRunner = _buildRunner ??
+        NativeAssetsBuildRunnerImpl(
+          projectUri,
+          packageConfig,
+          fileSystem,
+          environment.logger,
+        );
 
     final List<Uri> dependencies;
     switch (targetPlatform) {

packages/flutter_tools/lib/src/flutter_plugins.dart

@@ -26,14 +26,20 @@ import 'platform_plugins.dart';
 import 'plugins.dart';
 import 'project.dart';
 
-void _renderTemplateToFile(String template, Object? context, File file, TemplateRenderer templateRenderer) {
+Future<void> _renderTemplateToFile(
+  String template,
+  Object? context,
+  File file,
+  TemplateRenderer templateRenderer,
+) async {
   final String renderedTemplate = templateRenderer
     .renderString(template, context);
-  file.createSync(recursive: true);
-  file.writeAsStringSync(renderedTemplate);
+  await file.create(recursive: true);
+  await file.writeAsString(renderedTemplate);
 }
 
-Plugin? _pluginFromPackage(String name, Uri packageRoot, Set<String> appDependencies, {FileSystem? fileSystem}) {
+Future<Plugin?> _pluginFromPackage(String name, Uri packageRoot, Set<String> appDependencies,
+    {FileSystem? fileSystem}) async {
   final FileSystem fs = fileSystem ?? globals.fs;
   final File pubspecFile = fs.file(packageRoot.resolve('pubspec.yaml'));
   if (!pubspecFile.existsSync()) {
@@ -42,7 +48,7 @@ Plugin? _pluginFromPackage(String name, Uri packageRoot, Set<String> appDependen
   Object? pubspec;
 
   try {
-    pubspec = loadYaml(pubspecFile.readAsStringSync());
+    pubspec = loadYaml(await pubspecFile.readAsString());
   } on YamlException catch (err) {
     globals.printTrace('Failed to parse plugin manifest for $name: $err');
     // Do nothing, potentially not a plugin.
@@ -85,7 +91,7 @@ Future<List<Plugin>> findPlugins(FlutterProject project, { bool throwOnError = t
   );
   for (final Package package in packageConfig.packages) {
     final Uri packageRoot = package.packageUriRoot.resolve('..');
-    final Plugin? plugin = _pluginFromPackage(
+    final Plugin? plugin = await _pluginFromPackage(
       package.name,
       packageRoot,
       project.manifest.dependencies,
@@ -445,7 +451,7 @@ Future<void> _writeAndroidPluginRegistrant(FlutterProject project, List<Plugin>
       templateContent = _androidPluginRegistryTemplateOldEmbedding;
   }
   globals.printTrace('Generating $registryPath');
-  _renderTemplateToFile(
+  await _renderTemplateToFile(
     templateContent,
     templateContext,
     globals.fs.file(registryPath),
@@ -774,20 +780,20 @@ Future<void> _writeIOSPluginRegistrant(FlutterProject project, List<Plugin> plug
   };
   if (project.isModule) {
     final Directory registryDirectory = project.ios.pluginRegistrantHost;
-    _renderTemplateToFile(
+    await _renderTemplateToFile(
       _pluginRegistrantPodspecTemplate,
       context,
       registryDirectory.childFile('FlutterPluginRegistrant.podspec'),
       globals.templateRenderer,
     );
   }
-  _renderTemplateToFile(
+  await _renderTemplateToFile(
     _objcPluginRegistryHeaderTemplate,
     context,
     project.ios.pluginRegistrantHeader,
     globals.templateRenderer,
   );
-  _renderTemplateToFile(
+  await _renderTemplateToFile(
     _objcPluginRegistryImplementationTemplate,
     context,
     project.ios.pluginRegistrantImplementation,
@@ -829,13 +835,13 @@ Future<void> _writeLinuxPluginFiles(FlutterProject project, List<Plugin> plugins
 }
 
 Future<void> _writeLinuxPluginRegistrant(Directory destination, Map<String, Object> templateContext) async {
-  _renderTemplateToFile(
+  await _renderTemplateToFile(
     _linuxPluginRegistryHeaderTemplate,
     templateContext,
     destination.childFile('generated_plugin_registrant.h'),
     globals.templateRenderer,
   );
-  _renderTemplateToFile(
+  await _renderTemplateToFile(
     _linuxPluginRegistryImplementationTemplate,
     templateContext,
     destination.childFile('generated_plugin_registrant.cc'),
@@ -844,7 +850,7 @@ Future<void> _writeLinuxPluginRegistrant(Directory destination, Map<String, Obje
 }
 
 Future<void> _writePluginCmakefile(File destinationFile, Map<String, Object> templateContext, TemplateRenderer templateRenderer) async {
-  _renderTemplateToFile(
+  await _renderTemplateToFile(
     _pluginCmakefileTemplate,
     templateContext,
     destinationFile,
@@ -860,7 +866,7 @@ Future<void> _writeMacOSPluginRegistrant(FlutterProject project, List<Plugin> pl
     'framework': 'FlutterMacOS',
     'methodChannelPlugins': macosMethodChannelPlugins,
   };
-  _renderTemplateToFile(
+  await _renderTemplateToFile(
     _swiftPluginRegistryTemplate,
     context,
     project.macos.managedDirectory.childFile('GeneratedPluginRegistrant.swift'),
@@ -931,13 +937,13 @@ Future<void> writeWindowsPluginFiles(FlutterProject project, List<Plugin> plugin
 }
 
 Future<void> _writeCppPluginRegistrant(Directory destination, Map<String, Object> templateContext, TemplateRenderer templateRenderer) async {
-  _renderTemplateToFile(
+  await _renderTemplateToFile(
     _cppPluginRegistryHeaderTemplate,
     templateContext,
     destination.childFile('generated_plugin_registrant.h'),
     templateRenderer,
   );
-  _renderTemplateToFile(
+  await _renderTemplateToFile(
     _cppPluginRegistryImplementationTemplate,
     templateContext,
     destination.childFile('generated_plugin_registrant.cc'),
@@ -955,7 +961,7 @@ Future<void> _writeWebPluginRegistrant(FlutterProject project, List<Plugin> plug
 
   final String template = webPlugins.isEmpty ? _noopDartPluginRegistryTemplate : _dartPluginRegistryTemplate;
 
-  _renderTemplateToFile(
+  await _renderTemplateToFile(
     template,
     context,
     pluginFile,
@@ -1411,8 +1417,8 @@ Future<void> generateMainDartWithPluginRegistrant(
   final File newMainDart = rootProject.dartPluginRegistrant;
   if (resolutions.isEmpty) {
     try {
-      if (newMainDart.existsSync()) {
-        newMainDart.deleteSync();
+      if (await newMainDart.exists()) {
+        await newMainDart.delete();
       }
     } on FileSystemException catch (error) {
       globals.printWarning(
@@ -1428,7 +1434,7 @@ Future<void> generateMainDartWithPluginRegistrant(
     (templateContext[resolution.platform] as List<Object?>?)?.add(resolution.toMap());
   }
   try {
-    _renderTemplateToFile(
+    await _renderTemplateToFile(
       _dartPluginRegistryForNonWebTemplate,
       templateContext,
       newMainDart,

packages/flutter_tools/lib/src/native_assets.dart

@@ -5,7 +5,8 @@
 // Logic for native assets shared between all host OSes.
 
 import 'package:logging/logging.dart' as logging;
-import 'package:native_assets_builder/native_assets_builder.dart' as native_assets_builder;
+import 'package:native_assets_builder/native_assets_builder.dart' hide NativeAssetsBuildRunner;
+import 'package:native_assets_builder/native_assets_builder.dart' as native_assets_builder show NativeAssetsBuildRunner;
 import 'package:native_assets_cli/native_assets_cli.dart';
 import 'package:package_config/package_config_types.dart';
 
@@ -37,7 +38,7 @@ abstract class NativeAssetsBuildRunner {
   Future<List<Package>> packagesWithNativeAssets();
 
   /// Runs all [packagesWithNativeAssets] `build.dart` in dry run.
-  Future<native_assets_builder.DryRunResult> dryRun({
+  Future<DryRunResult> dryRun({
     required bool includeParentEnvironment,
     required LinkModePreference linkModePreference,
     required OS targetOs,
@@ -45,7 +46,7 @@ abstract class NativeAssetsBuildRunner {
   });
 
   /// Runs all [packagesWithNativeAssets] `build.dart`.
-  Future<native_assets_builder.BuildResult> build({
+  Future<BuildResult> build({
     required bool includeParentEnvironment,
     required BuildMode buildMode,
     required LinkModePreference linkModePreference,
@@ -62,9 +63,15 @@ abstract class NativeAssetsBuildRunner {
 
 /// Uses `package:native_assets_builder` for its implementation.
 class NativeAssetsBuildRunnerImpl implements NativeAssetsBuildRunner {
-  NativeAssetsBuildRunnerImpl(this.projectUri, this.fileSystem, this.logger);
+  NativeAssetsBuildRunnerImpl(
+    this.projectUri,
+    this.packageConfig,
+    this.fileSystem,
+    this.logger,
+  );
 
   final Uri projectUri;
+  final PackageConfig packageConfig;
   final FileSystem fileSystem;
   final Logger logger;
 
@@ -90,8 +97,6 @@ class NativeAssetsBuildRunnerImpl implements NativeAssetsBuildRunner {
     dartExecutable: _dartExecutable,
   );
 
-  native_assets_builder.PackageLayout? _packageLayout;
-
   @override
   Future<bool> hasPackageConfig() {
     final File packageConfigJson = fileSystem
@@ -103,27 +108,35 @@ class NativeAssetsBuildRunnerImpl implements NativeAssetsBuildRunner {
 
   @override
   Future<List<Package>> packagesWithNativeAssets() async {
-    _packageLayout ??= await native_assets_builder.PackageLayout.fromRootPackageRoot(projectUri);
-    return _packageLayout!.packagesWithNativeAssets;
+    final PackageLayout packageLayout = PackageLayout.fromPackageConfig(
+      packageConfig,
+      projectUri.resolve('.dart_tool/package_config.json'),
+    );
+    return packageLayout.packagesWithNativeAssets;
   }
 
   @override
-  Future<native_assets_builder.DryRunResult> dryRun({
+  Future<DryRunResult> dryRun({
     required bool includeParentEnvironment,
     required LinkModePreference linkModePreference,
     required OS targetOs,
     required Uri workingDirectory,
   }) {
+    final PackageLayout packageLayout = PackageLayout.fromPackageConfig(
+      packageConfig,
+      projectUri.resolve('.dart_tool/package_config.json'),
+    );
     return _buildRunner.dryRun(
       includeParentEnvironment: includeParentEnvironment,
       linkModePreference: linkModePreference,
       targetOs: targetOs,
       workingDirectory: workingDirectory,
+      packageLayout: packageLayout,
     );
   }
 
   @override
-  Future<native_assets_builder.BuildResult> build({
+  Future<BuildResult> build({
     required bool includeParentEnvironment,
     required BuildMode buildMode,
     required LinkModePreference linkModePreference,
@@ -133,6 +146,10 @@ class NativeAssetsBuildRunnerImpl implements NativeAssetsBuildRunner {
     int? targetAndroidNdkApi,
     IOSSdk? targetIOSSdk,
   }) {
+    final PackageLayout packageLayout = PackageLayout.fromPackageConfig(
+      packageConfig,
+      projectUri.resolve('.dart_tool/package_config.json'),
+    );
     return _buildRunner.build(
       buildMode: buildMode,
       cCompilerConfig: cCompilerConfig,
@@ -142,6 +159,7 @@ class NativeAssetsBuildRunnerImpl implements NativeAssetsBuildRunner {
       targetAndroidNdkApi: targetAndroidNdkApi,
       targetIOSSdk: targetIOSSdk,
       workingDirectory: workingDirectory,
+      packageLayout: packageLayout,
     );
   }
 

packages/flutter_tools/lib/src/run_hot.dart

@@ -366,7 +366,12 @@ class HotRunner extends ResidentRunner {
     await _calculateTargetPlatform();
 
     final Uri projectUri = Uri.directory(projectRootPath);
-    _buildRunner ??= NativeAssetsBuildRunnerImpl(projectUri, fileSystem, globals.logger);
+    _buildRunner ??= NativeAssetsBuildRunnerImpl(
+      projectUri,
+      debuggingOptions.buildInfo.packageConfig,
+      fileSystem,
+      globals.logger,
+    );
     final Uri? nativeAssetsYaml = await dryRunNativeAssets(
       projectUri: projectUri,
       fileSystem: fileSystem,

packages/flutter_tools/lib/src/test/test_compiler.dart

@@ -168,7 +168,12 @@ class TestCompiler {
 
       Uri? nativeAssetsYaml;
       final Uri projectUri = FlutterProject.current().directory.uri;
-      final NativeAssetsBuildRunner buildRunner = NativeAssetsBuildRunnerImpl(projectUri, globals.fs, globals.logger);
+      final NativeAssetsBuildRunner buildRunner = NativeAssetsBuildRunnerImpl(
+        projectUri,
+        buildInfo.packageConfig,
+        globals.fs,
+        globals.logger,
+      );
       if (globals.platform.isMacOS) {
         (nativeAssetsYaml, _) = await buildNativeAssetsMacOS(
           buildMode: BuildMode.debug,

packages/flutter_tools/pubspec.yaml

@@ -52,7 +52,7 @@ dependencies:
 
   cli_config: 0.1.1
   graphs: 2.3.1
-  native_assets_builder: 0.2.0
+  native_assets_builder: 0.2.3
   native_assets_cli: 0.2.0
 
   # We depend on very specific internal implementation details of the
@@ -112,4 +112,4 @@ dartdoc:
   # Exclude this package from the hosted API docs.
   nodoc: true
 
-# PUBSPEC CHECKSUM: 284b
+# PUBSPEC CHECKSUM: 7f4e

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

@@ -55,11 +55,15 @@ void main() {
   });
 
   testUsingContext('NativeAssets throws error if missing ios archs', () async {
+    await createPackageConfig(iosEnvironment);
+
     iosEnvironment.defines.remove(kIosArchs);
     expect(const NativeAssets().build(iosEnvironment), throwsA(isA<MissingDefineException>()));
   });
 
   testUsingContext('NativeAssets throws error if missing sdk root', () async {
+    await createPackageConfig(iosEnvironment);
+
     iosEnvironment.defines.remove(kSdkRoot);
     expect(const NativeAssets().build(iosEnvironment), throwsA(isA<MissingDefineException>()));
   });
@@ -78,6 +82,8 @@ void main() {
         ),
       },
       () async {
+        await createPackageConfig(iosEnvironment);
+
         final NativeAssetsBuildRunner buildRunner = FakeNativeAssetsBuildRunner();
         await NativeAssets(buildRunner: buildRunner).build(iosEnvironment);
 
@@ -95,6 +101,8 @@ void main() {
       FeatureFlags: () => TestFeatureFlags(isNativeAssetsEnabled: true),
     },
     () async {
+      await createPackageConfig(iosEnvironment);
+
       final NativeAssetsBuildRunner buildRunner = FakeNativeAssetsBuildRunner(
         buildResult: FakeNativeAssetsBuilderResult(assets: <native_assets_cli.Asset>[
           native_assets_cli.Asset(
@@ -138,3 +146,11 @@ void main() {
     },
   );
 }
+
+Future<void> createPackageConfig(Environment iosEnvironment) async {
+  final File packageConfig = iosEnvironment.projectDir
+      .childDirectory('.dart_tool')
+      .childFile('package_config.json');
+  await packageConfig.parent.create();
+  await packageConfig.create();
+}

packages/flutter_tools/test/general.shard/macos/native_assets_test.dart

@@ -10,6 +10,7 @@ import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/build_info.dart';
 import 'package:flutter_tools/src/build_system/build_system.dart';
+import 'package:flutter_tools/src/dart/package_map.dart';
 import 'package:flutter_tools/src/features.dart';
 import 'package:flutter_tools/src/globals.dart' as globals;
 import 'package:flutter_tools/src/macos/native_assets.dart';
@@ -373,7 +374,22 @@ InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault
       return;
     }
 
-    final NativeAssetsBuildRunner runner = NativeAssetsBuildRunnerImpl(projectUri, fileSystem, logger);
+    final File packagesFile = fileSystem
+        .directory(projectUri)
+        .childDirectory('.dart_tool')
+        .childFile('package_config.json');
+    await packagesFile.parent.create();
+    await packagesFile.create();
+    final PackageConfig packageConfig = await loadPackageConfigWithLogging(
+      packagesFile,
+      logger: environment.logger,
+    );
+    final NativeAssetsBuildRunner runner = NativeAssetsBuildRunnerImpl(
+      projectUri,
+      packageConfig,
+      fileSystem,
+      logger,
+    );
     final CCompilerConfig result = await runner.cCompilerConfig;
     expect(
       result.cc,