[jnigen] Fix crash on Kotlin wildcards

pkgs/jnigen/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.13.1-wip
+
+- Fixed a bug where Kotlin wildcards would crash the code generation.
+
 ## 0.13.0
 
 - **Breaking Change**([#1516](https://github.com/dart-lang/native/issues/1516)):

pkgs/jnigen/lib/src/bindings/kotlin_processor.dart

@@ -254,16 +254,20 @@ class _KotlinTypeProcessor extends TypeVisitor<void> {
   @override
   void visitDeclaredType(DeclaredType node) {
     for (var i = 0; i < node.params.length; ++i) {
-      node.params[i].accept(_KotlinTypeProcessor(kotlinType.arguments[i].type));
+      if (kotlinType.arguments[i] case final KotlinTypeProjection projection) {
+        node.params[i].accept(_KotlinTypeProcessor(projection.type));
+      }
     }
     super.visitDeclaredType(node);
   }
 
   @override
   void visitArrayType(ArrayType node) {
     if (kotlinType.arguments.isNotEmpty) {
-      node.elementType
-          .accept(_KotlinTypeProcessor(kotlinType.arguments.first.type));
+      if (kotlinType.arguments.first
+          case final KotlinTypeProjection projection) {
+        node.elementType.accept(_KotlinTypeProcessor(projection.type));
+      }
     }
     super.visitArrayType(node);
   }

pkgs/jnigen/lib/src/elements/elements.dart

@@ -78,6 +78,7 @@ class ClassDecl with ClassMember, Annotated implements Element<ClassDecl> {
     this.kotlinPackage,
   });
 
+  @JsonKey(includeFromJson: false)
   bool isExcluded;
 
   @override
@@ -625,6 +626,7 @@ class Method with ClassMember, Annotated implements Element<Method> {
     required this.returnType,
   });
 
+  @JsonKey(includeFromJson: false)
   bool isExcluded;
 
   @override
@@ -728,6 +730,7 @@ class Field with ClassMember, Annotated implements Element<Field> {
     this.defaultValue,
   });
 
+  @JsonKey(includeFromJson: false)
   bool isExcluded;
 
   @override
@@ -1120,7 +1123,7 @@ class KotlinType implements Element<KotlinType> {
   final String kind;
   final String? name;
   final int id;
-  final List<KotlinTypeProjection> arguments;
+  final List<KotlinTypeArgument> arguments;
   final bool isNullable;
 
   factory KotlinType.fromJson(Map<String, dynamic> json) =>
@@ -1190,21 +1193,31 @@ class KotlinValueParameter implements Element<KotlinValueParameter> {
   }
 }
 
-@JsonSerializable(createToJson: false)
-class KotlinTypeProjection implements Element<KotlinTypeProjection> {
+sealed class KotlinTypeArgument implements Element<KotlinTypeArgument> {
+  KotlinTypeArgument();
+
+  factory KotlinTypeArgument.fromJson(Map<String, dynamic> json) =>
+      json['type'] == null
+          ? KotlinWildcard()
+          : KotlinTypeProjection(
+              type: KotlinType.fromJson(json['type'] as Map<String, dynamic>),
+              variance: $enumDecode(_$KmVarianceEnumMap, json['variance']),
+            );
+
+  @override
+  R accept<R>(Visitor<KotlinTypeArgument, R> v) {
+    return v.visit(this);
+  }
+}
+
+class KotlinWildcard extends KotlinTypeArgument {}
+
+class KotlinTypeProjection extends KotlinTypeArgument {
   KotlinTypeProjection({
     required this.type,
     required this.variance,
   });
 
   final KotlinType type;
   final KmVariance variance;
-
-  factory KotlinTypeProjection.fromJson(Map<String, dynamic> json) =>
-      _$KotlinTypeProjectionFromJson(json);
-
-  @override
-  R accept<R>(Visitor<KotlinTypeProjection, R> v) {
-    return v.visit(this);
-  }
 }

pkgs/jnigen/pubspec.yaml

@@ -4,7 +4,7 @@
 
 name: jnigen
 description: A Dart bindings generator for Java and Kotlin that uses JNI under the hood to interop with Java virtual machine.
-version: 0.13.0
+version: 0.13.1-wip
 repository: https://github.com/dart-lang/native/tree/main/pkgs/jnigen
 issue_tracker: https://github.com/dart-lang/native/issues?q=is%3Aissue+is%3Aopen+label%3Apackage%3Ajnigen
 

pkgs/jnigen/test/kotlin_test/bindings/kotlin.dart

@@ -994,6 +994,31 @@ class Nullability<$T extends jni$_.JObject?, $U extends jni$_.JObject>
         .object<jni$_.JString?>(const jni$_.JStringNullableType());
   }
 
+  static final _id_list = _class.instanceMethodId(
+    r'list',
+    r'()Ljava/util/List;',
+  );
+
+  static final _list = jni$_.ProtectedJniExtensions.lookup<
+          jni$_.NativeFunction<
+              jni$_.JniResult Function(
+                jni$_.Pointer<jni$_.Void>,
+                jni$_.JMethodIDPtr,
+              )>>('globalEnv_CallObjectMethod')
+      .asFunction<
+          jni$_.JniResult Function(
+            jni$_.Pointer<jni$_.Void>,
+            jni$_.JMethodIDPtr,
+          )>();
+
+  /// from: `public final java.util.List list()`
+  /// The returned object must be released after use, by calling the [release] method.
+  jni$_.JList<jni$_.JObject?> list() {
+    return _list(reference.pointer, _id_list as jni$_.JMethodIDPtr)
+        .object<jni$_.JList<jni$_.JObject?>>(
+            const jni$_.JListType<jni$_.JObject?>(jni$_.JObjectNullableType()));
+  }
+
   static final _id_methodGenericEcho = _class.instanceMethodId(
     r'methodGenericEcho',
     r'(Ljava/lang/Object;)Ljava/lang/Object;',

pkgs/jnigen/test/kotlin_test/kotlin/src/main/kotlin/com/github/dart_lang/jnigen/Nullability.kt

@@ -14,6 +14,10 @@ public class Nullability<T, U: Any>(val t: T, val u: U, var nullableU: U?) {
         return if (returnNull) null else "hello"
     }
 
+    public fun list(): List<*> {
+        return listOf("hello", 42)
+    }
+
     public fun <V: Any> methodGenericEcho(v: V): V {
         return v
     }

pkgs/jnigen/test/kotlin_test/runtime_test_registrant.dart

@@ -81,6 +81,14 @@ void registerTests(String groupName, TestRunnerCallback test) {
       test('Methods', () {
         using((arena) {
           final obj = testObject(arena);
+          expect(
+            obj
+                .list()
+                .first!
+                .as(JString.type, releaseOriginal: true)
+                .toDartString(releaseOriginal: true),
+            'hello',
+          );
           expect(obj.hello().toDartString(releaseOriginal: true), 'hello');
           expect(
             obj.nullableHello(false)!.toDartString(releaseOriginal: true),