[flutter_tools] fix tests with no native assets running native asset build

packages/flutter_tools/lib/src/ios/native_assets.dart

@@ -23,7 +23,7 @@ Future<Uri?> dryRunNativeAssetsIOS({
   required Uri projectUri,
   required FileSystem fileSystem,
 }) async {
-  if (await hasNoPackageConfig(buildRunner) || await isDisabledAndNoNativeAssets(buildRunner)) {
+  if (!await nativeBuildRequired(buildRunner)) {
     return null;
   }
 
@@ -72,7 +72,7 @@ Future<List<Uri>> buildNativeAssetsIOS({
   required Uri yamlParentDirectory,
   required FileSystem fileSystem,
 }) async {
-  if (await hasNoPackageConfig(buildRunner) || await isDisabledAndNoNativeAssets(buildRunner)) {
+  if (!await nativeBuildRequired(buildRunner)) {
     await writeNativeAssetsYaml(<Asset>[], yamlParentDirectory, fileSystem);
     return <Uri>[];
   }

packages/flutter_tools/lib/src/linux/native_assets.dart

@@ -23,7 +23,7 @@ Future<Uri?> dryRunNativeAssetsLinux({
   bool flutterTester = false,
   required FileSystem fileSystem,
 }) async {
-  if (await hasNoPackageConfig(buildRunner) || await isDisabledAndNoNativeAssets(buildRunner)) {
+  if (!await nativeBuildRequired(buildRunner)) {
     return null;
   }
 
@@ -90,7 +90,7 @@ Future<(Uri? nativeAssetsYaml, List<Uri> dependencies)> buildNativeAssetsLinux({
     // CMake requires the folder to exist to do copying.
     await buildDir.create(recursive: true);
   }
-  if (await hasNoPackageConfig(buildRunner) || await isDisabledAndNoNativeAssets(buildRunner)) {
+  if (!await nativeBuildRequired(buildRunner)) {
     final Uri nativeAssetsYaml = await writeNativeAssetsYaml(<Asset>[], yamlParentDirectory ?? buildUri_, fileSystem);
     return (nativeAssetsYaml, <Uri>[]);
   }

packages/flutter_tools/lib/src/macos/native_assets.dart

@@ -23,7 +23,7 @@ Future<Uri?> dryRunNativeAssetsMacOS({
   bool flutterTester = false,
   required FileSystem fileSystem,
 }) async {
-  if (await hasNoPackageConfig(buildRunner) || await isDisabledAndNoNativeAssets(buildRunner)) {
+  if (!await nativeBuildRequired(buildRunner)) {
     return null;
   }
 
@@ -77,7 +77,7 @@ Future<(Uri? nativeAssetsYaml, List<Uri> dependencies)> buildNativeAssetsMacOS({
 }) async {
   const OS targetOs = OS.macOS;
   final Uri buildUri_ = nativeAssetsBuildUri(projectUri, targetOs);
-  if (await hasNoPackageConfig(buildRunner) || await isDisabledAndNoNativeAssets(buildRunner)) {
+  if (!await nativeBuildRequired(buildRunner)) {
     final Uri nativeAssetsYaml = await writeNativeAssetsYaml(<Asset>[], yamlParentDirectory ?? buildUri_, fileSystem);
     return (nativeAssetsYaml, <Uri>[]);
   }

packages/flutter_tools/lib/src/native_assets.dart

@@ -214,45 +214,45 @@ BuildMode nativeAssetsBuildMode(build_info.BuildMode buildMode) {
 ///
 /// Native asset builds cannot be run without a package config. If there is
 /// no package config, leave a logging trace about that.
-Future<bool> hasNoPackageConfig(NativeAssetsBuildRunner buildRunner) async {
+Future<bool> _hasNoPackageConfig(NativeAssetsBuildRunner buildRunner) async {
   final bool packageConfigExists = await buildRunner.hasPackageConfig();
   if (!packageConfigExists) {
     globals.logger.printTrace('No package config found. Skipping native assets compilation.');
   }
   return !packageConfigExists;
 }
 
-/// Checks that if native assets is disabled, none of the dependencies declare
-/// native assets.
-///
-/// If any of the dependencies have native assets, but native assets are
-/// disabled, exits the tool.
-Future<bool> isDisabledAndNoNativeAssets(NativeAssetsBuildRunner buildRunner) async {
-  if (featureFlags.isNativeAssetsEnabled) {
+Future<bool> nativeBuildRequired(NativeAssetsBuildRunner buildRunner) async {
+  if (await _hasNoPackageConfig(buildRunner)) {
     return false;
   }
   final List<Package> packagesWithNativeAssets = await buildRunner.packagesWithNativeAssets();
   if (packagesWithNativeAssets.isEmpty) {
-    return true;
+    return false;
   }
-  final String packageNames = packagesWithNativeAssets.map((Package p) => p.name).join(' ');
-  throwToolExit(
-    'Package(s) $packageNames require the native assets feature to be enabled. '
-    'Enable using `flutter config --enable-native-assets`.',
-  );
+
+  if (!featureFlags.isNativeAssetsEnabled) {
+    final String packageNames = packagesWithNativeAssets.map((Package p) => p.name).join(' ');
+    throwToolExit(
+      'Package(s) $packageNames require the native assets feature to be enabled. '
+      'Enable using `flutter config --enable-native-assets`.',
+    );
+  }
+  return true;
 }
 
 /// Ensures that either this project has no native assets, or that native assets
 /// are supported on that operating system.
 ///
 /// Exits the tool if the above condition is not satisfied.
+// TODO(fujino): this does not appear to do what it says it does.
 Future<void> ensureNoNativeAssetsOrOsIsSupported(
   Uri workingDirectory,
   String os,
   FileSystem fileSystem,
   NativeAssetsBuildRunner buildRunner,
 ) async {
-  if (await hasNoPackageConfig(buildRunner)) {
+  if (await _hasNoPackageConfig(buildRunner)) {
     return;
   }
   final List<Package> packagesWithNativeAssets = await buildRunner.packagesWithNativeAssets();
@@ -345,12 +345,7 @@ Future<Uri?> dryRunNativeAssets({
           buildRunner: buildRunner,
         );
       } else {
-        await ensureNoNativeAssetsOrOsIsSupported(
-          projectUri,
-          const LocalPlatform().operatingSystem,
-          fileSystem,
-          buildRunner,
-        );
+        await nativeBuildRequired(buildRunner);
         nativeAssetsYaml = null;
       }
     case build_info.TargetPlatform.linux_arm64:
@@ -389,7 +384,7 @@ Future<Uri?> dryRunNativeAssetsMultipeOSes({
   required FileSystem fileSystem,
   required Iterable<build_info.TargetPlatform> targetPlatforms,
 }) async {
-  if (await hasNoPackageConfig(buildRunner) || await isDisabledAndNoNativeAssets(buildRunner)) {
+  if (await nativeBuildRequired(buildRunner)) {
     return null;
   }
 

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

@@ -6,6 +6,7 @@ import 'package:file/file.dart';
 import 'package:file/memory.dart';
 import 'package:file_testing/file_testing.dart';
 import 'package:flutter_tools/src/artifacts.dart';
+import 'package:flutter_tools/src/base/common.dart';
 import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/logger.dart';
 import 'package:flutter_tools/src/base/platform.dart';
@@ -86,6 +87,24 @@ void main() {
     );
   });
 
+  testUsingContext('does not throw if clang not present but no native assets present', overrides: <Type, Generator>{
+    FeatureFlags: () => TestFeatureFlags(isNativeAssetsEnabled: true),
+    ProcessManager: () => FakeProcessManager.empty(),
+  }, () async {
+    final File packageConfig = environment.projectDir.childFile('.dart_tool/package_config.json');
+    await packageConfig.create(recursive: true);
+    await buildNativeAssetsLinux(
+      projectUri: projectUri,
+      buildMode: BuildMode.debug,
+      fileSystem: fileSystem,
+      buildRunner: _BuildRunnerWithoutClang(),
+    );
+    expect(
+      (globals.logger as BufferLogger).traceText,
+      isNot(contains('Building native assets for ')),
+    );
+  });
+
   testUsingContext('dry run for multiple OSes with no package config', overrides: <Type, Generator>{
     ProcessManager: () => FakeProcessManager.empty(),
   }, () async {
@@ -372,3 +391,8 @@ void main() {
     expect(result.cc, Uri.file('/some/path/to/clang'));
   });
 }
+
+class _BuildRunnerWithoutClang extends FakeNativeAssetsBuildRunner {
+  @override
+  Future<CCompilerConfig> get cCompilerConfig async => throwToolExit('Failed to find clang++ on the PATH.');
+}