[ffigen] skip SWIFT_UNAVAILABLE

pkgs/ffigen/lib/src/code_generator/objc_interface.dart

@@ -25,6 +25,7 @@ class ObjCInterface extends BindingType with ObjCMethods, HasLocalScope {
   final categories = <ObjCCategory>[];
   final subtypes = <ObjCInterface>[];
   final ApiAvailability apiAvailability;
+  final Set<String> swiftUnavailableSelectors = {};
 
   // Filled by ListBindingsVisitation.
   bool generateAsStub = false;
@@ -168,7 +169,9 @@ ${generateInstanceMethodBindings(w, this)}
               m.originalName == 'new',
         )
         .firstOrNull;
-    if (newMethod != null && originalName != 'NSString') {
+    if (newMethod != null &&
+        originalName != 'NSString' &&
+        !swiftUnavailableSelectors.contains('new')) {
       s.write('''
   /// Returns a new instance of $name constructed with the default `new` method.
   $name() : this.as(${newMethod.name}().object\$);

pkgs/ffigen/lib/src/header_parser/sub_parsers/api_availability.dart

@@ -19,6 +19,7 @@ class ApiAvailability {
   final bool alwaysUnavailable;
   final PlatformAvailability? ios;
   final PlatformAvailability? macos;
+  final bool swiftUnavailable;
 
   late final Availability availability;
 
@@ -27,6 +28,7 @@ class ApiAvailability {
     this.alwaysUnavailable = false,
     this.ios,
     this.macos,
+    this.swiftUnavailable = false,
     required ExternalVersions? externalVersions,
   }) {
     availability = _getAvailability(externalVersions);
@@ -64,6 +66,7 @@ class ApiAvailability {
 
     PlatformAvailability? ios;
     PlatformAvailability? macos;
+    var swiftIsUnavailable = false;
 
     for (var i = 0; i < platformsLength; ++i) {
       final platform = platforms[i];
@@ -80,6 +83,9 @@ class ApiAvailability {
         case 'macos':
           macos = platformAvailability..name = 'macOS';
           break;
+        case 'swift':
+          if (platformAvailability.unavailable) swiftIsUnavailable = true;
+          break;
       }
     }
 
@@ -88,6 +94,7 @@ class ApiAvailability {
       alwaysUnavailable: alwaysUnavailable.value != 0,
       ios: ios,
       macos: macos,
+      swiftUnavailable: swiftIsUnavailable,
       externalVersions: context.config.objectiveC?.externalVersions,
     );
 

pkgs/ffigen/lib/src/header_parser/sub_parsers/objcinterfacedecl_parser.dart

@@ -77,6 +77,25 @@ void fillObjCInterfaceMethodsIfNeeded(
     'Name: ${itf.originalName}, ${cursor.completeStringRepr()}',
   );
 
+  if (!cursor.isInSystemHeader()) {
+    cursor.visitChildren((child) {
+      final isMethodDecl =
+          child.kind ==
+              clang_types.CXCursorKind.CXCursor_ObjCInstanceMethodDecl ||
+          child.kind == clang_types.CXCursorKind.CXCursor_ObjCClassMethodDecl;
+      if (isMethodDecl) {
+        final avail = ApiAvailability.fromCursor(child, context);
+        if (avail.swiftUnavailable) {
+          itf.swiftUnavailableSelectors.add(child.spelling());
+          context.logger.info(
+            'Marking swift-unavailable: '
+            '${itf.originalName}.${child.spelling()}',
+          );
+        }
+      }
+    });
+  }
+
   final itfDecl = Declaration(usr: itf.usr, originalName: itf.originalName);
   cursor.visitChildren((child) {
     switch (child.kind) {

pkgs/ffigen/test/native_objc_test/swift_unavailable_test.dart

@@ -0,0 +1,83 @@
+// Copyright (c) 2025, the Dart project authors. Please see the AUTHORS file
+// 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.
+
+// Objective C support is only available on mac.
+@TestOn('mac-os')
+library;
+
+import 'dart:io';
+
+import 'package:ffigen/ffigen.dart';
+import 'package:path/path.dart' as path;
+import 'package:test/test.dart';
+
+import '../test_utils.dart';
+
+void main() {
+  group('swift_unavailable', () {
+    late final String bindings;
+
+    setUpAll(() {
+      FfiGenerator(
+        output: Output(
+          dartFile: Uri.file(
+            path.join(
+              packagePathForTests,
+              'test',
+              'native_objc_test',
+              'swift_unavailable_bindings.dart',
+            ),
+          ),
+          format: false,
+          style: const DynamicLibraryBindings(
+            wrapperName: 'SwiftUnavailableTestLibrary',
+            wrapperDocComment: 'Tests SWIFT_UNAVAILABLE annotation',
+          ),
+        ),
+        headers: Headers(
+          entryPoints: [
+            Uri.file(
+              path.join(
+                packagePathForTests,
+                'test',
+                'native_objc_test',
+                'swift_unavailable_test.m',
+              ),
+            ),
+          ],
+        ),
+        objectiveC: ObjectiveC(
+          interfaces: Interfaces(
+            include: (decl) => {'Animal'}.contains(decl.originalName),
+          ),
+        ),
+      ).generate(logger: createTestLogger());
+
+      bindings = File(
+        path.join(
+          packagePathForTests,
+          'test',
+          'native_objc_test',
+          'swift_unavailable_bindings.dart',
+        ),
+      ).readAsStringSync();
+    });
+
+    test('initWithName is generated (designated initializer)', () {
+      expect(bindings, contains('initWithName'));
+    });
+
+    test('init is NOT generated (SWIFT_UNAVAILABLE)', () {
+      expect(RegExp(r"'init'\b").hasMatch(bindings), isFalse);
+    });
+
+    test('new is NOT generated (SWIFT_UNAVAILABLE_MSG)', () {
+      expect(bindings, isNot(contains("'new'")));
+    });
+
+    test('no-arg Animal() constructor is NOT generated', () {
+      expect(bindings, isNot(contains('Animal()')));
+    });
+  });
+}

pkgs/ffigen/test/native_objc_test/swift_unavailable_test.m

@@ -0,0 +1,20 @@
+// Copyright (c) 2025, the Dart project authors. Please see the AUTHORS file
+// 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 <Foundation/Foundation.h>
+
+#define SWIFT_UNAVAILABLE \
+  __attribute__((availability(swift, unavailable)))
+#define SWIFT_UNAVAILABLE_MSG(msg) \
+  __attribute__((availability(swift, unavailable, message = msg)))
+#define OBJC_DESIGNATED_INITIALIZER \
+  __attribute__((objc_designated_initializer))
+
+@interface Animal : NSObject
+@property(nonatomic, copy) NSString* _Nonnull name;
+- (nonnull instancetype)initWithName:(NSString* _Nonnull)name
+    OBJC_DESIGNATED_INITIALIZER;
+- (nonnull instancetype)init SWIFT_UNAVAILABLE;
++ (nonnull instancetype)new SWIFT_UNAVAILABLE_MSG("-init is unavailable");
+@end