Handle hidden dot files in iOS framework bundles (#99771)

dev/devicelab/bin/tasks/module_test_ios.dart

@@ -79,6 +79,26 @@ Future<void> main() async {
         );
       }
 
+      section('Build ephemeral host app when SDK is on external disk');
+
+      // Pretend the SDK was on an external drive with stray "._" files in the xcframework
+      // and build again.
+      Directory(path.join(
+        projectDir.path,
+        '.ios',
+        'Flutter',
+        'engine',
+        'Flutter.xcframework',
+        '._ios-arm64_x86_64-simulator',
+      )).createSync(recursive: true);
+
+      await inDirectory(projectDir, () async {
+        await flutter(
+          'build',
+          options: <String>['ios', '--no-codesign', '--simulator', '--debug'],
+        );
+      });
+
       section('Clean build');
 
       await inDirectory(projectDir, () async {

packages/flutter_tools/bin/podhelper.rb

@@ -60,6 +60,7 @@ def flutter_additional_ios_build_settings(target)
     # Profile can't be derived from the CocoaPods build configuration. Use release framework (for linking only).
     configuration_engine_dir = build_configuration.type == :debug ? debug_framework_dir : release_framework_dir
     Dir.new(configuration_engine_dir).each_child do |xcframework_file|
+      continue if xcframework_file.start_with?(".") # Hidden file, possibly on external disk.
       if xcframework_file.end_with?("-simulator") # ios-arm64_x86_64-simulator
         build_configuration.build_settings['FRAMEWORK_SEARCH_PATHS[sdk=iphonesimulator*]'] = "\"#{configuration_engine_dir}/#{xcframework_file}\" $(inherited)"
       elsif xcframework_file.start_with?("ios-") # ios-armv7_arm64