Native: emit _Nullable_result attribute when generating Objective-C header

^KT-47042 Fixed

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/objcexport/ObjCExportHeaderGenerator.kt

@@ -654,10 +654,14 @@ internal class ObjCExportTranslatorImpl(
                         ObjCPointerType(ObjCNullableReferenceType(ObjCClassType("NSError")), nullable = true)
 
                     MethodBridgeValueParameter.SuspendCompletion -> {
+                        val resultType = when (val it = mapReferenceType(method.returnType!!, objCExportScope)) {
+                            is ObjCNonNullReferenceType -> ObjCNullableReferenceType(it, isNullableResult = false)
+                            is ObjCNullableReferenceType -> ObjCNullableReferenceType(it.nonNullType, isNullableResult = true)
+                        }
                         ObjCBlockPointerType(
                                 returnType = ObjCVoidType,
                                 parameterTypes = listOf(
-                                        mapReferenceType(method.returnType!!, objCExportScope).makeNullable(),
+                                        resultType,
                                         ObjCNullableReferenceType(ObjCClassType("NSError"))
                                 )
                         )
@@ -1049,11 +1053,20 @@ abstract class ObjCExportHeaderGenerator internal constructor(
         }
         add("")
 
+        // If _Nullable_result is not supported, then use _Nullable:
+        add("#pragma push_macro(\"$objcNullableResultAttribute\")")
+        add("#if !__has_feature(nullability_nullable_result)")
+        add("#undef $objcNullableResultAttribute")
+        add("#define $objcNullableResultAttribute $objcNullableAttribute")
+        add("#endif")
+        add("")
+
         stubs.forEach {
             addAll(StubRenderer.render(it, shouldExportKDoc))
             add("")
         }
 
+        add("#pragma pop_macro(\"$objcNullableResultAttribute\")")
         add("#pragma clang diagnostic pop")
         add("NS_ASSUME_NONNULL_END")
     }

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/objcexport/objcTypes.kt

@@ -30,9 +30,13 @@ sealed class ObjCReferenceType : ObjCType()
 sealed class ObjCNonNullReferenceType : ObjCReferenceType()
 
 data class ObjCNullableReferenceType(
-        val nonNullType: ObjCNonNullReferenceType
+        val nonNullType: ObjCNonNullReferenceType,
+        val isNullableResult: Boolean = false
 ) : ObjCReferenceType() {
-    override fun render(attrsAndName: String) = nonNullType.render(" _Nullable".withAttrsAndName(attrsAndName))
+    override fun render(attrsAndName: String): String {
+        val attribute = if (isNullableResult) objcNullableResultAttribute else objcNullableAttribute
+        return nonNullType.render(" $attribute".withAttrsAndName(attrsAndName))
+    }
 }
 
 data class ObjCClassType(
@@ -139,7 +143,7 @@ data class ObjCPointerType(
 ) : ObjCType() {
     override fun render(attrsAndName: String) =
             pointee.render("*${if (nullable) {
-                " _Nullable".withAttrsAndName(attrsAndName)
+                " $objcNullableAttribute".withAttrsAndName(attrsAndName)
             } else {
                 attrsAndName
             }}")
@@ -208,7 +212,5 @@ internal fun ObjCType.makeNullableIfReferenceOrPointer(): ObjCType = when (this)
     is ObjCNullableReferenceType, is ObjCRawType, is ObjCPrimitiveType, ObjCVoidType -> this
 }
 
-internal fun ObjCReferenceType.makeNullable(): ObjCNullableReferenceType = when (this) {
-    is ObjCNonNullReferenceType -> ObjCNullableReferenceType(this)
-    is ObjCNullableReferenceType -> this
-}
+const val objcNullableAttribute = "_Nullable"
+const val objcNullableResultAttribute = "_Nullable_result"

kotlin-native/backend.native/tests/objcexport/expectedLazy.h

@@ -174,7 +174,7 @@ __attribute__((swift_name("SuspendBridge")))
  @note This method converts instances of CancellationException to errors.
  Other uncaught Kotlin exceptions are fatal.
 */
-- (void)intAsAnyValue:(id _Nullable)value completionHandler:(void (^)(id _Nullable, NSError * _Nullable))completionHandler __attribute__((swift_name("intAsAny(value:completionHandler:)")));
+- (void)intAsAnyValue:(id _Nullable)value completionHandler:(void (^)(id _Nullable_result, NSError * _Nullable))completionHandler __attribute__((swift_name("intAsAny(value:completionHandler:)")));
 
 /**
  @note This method converts instances of CancellationException to errors.
@@ -186,7 +186,7 @@ __attribute__((swift_name("SuspendBridge")))
  @note This method converts instances of CancellationException to errors.
  Other uncaught Kotlin exceptions are fatal.
 */
-- (void)unitAsAnyValue:(id _Nullable)value completionHandler:(void (^)(id _Nullable, NSError * _Nullable))completionHandler __attribute__((swift_name("unitAsAny(value:completionHandler:)")));
+- (void)unitAsAnyValue:(id _Nullable)value completionHandler:(void (^)(id _Nullable_result, NSError * _Nullable))completionHandler __attribute__((swift_name("unitAsAny(value:completionHandler:)")));
 
 /**
  @note This method converts all Kotlin exceptions to errors.
@@ -201,7 +201,7 @@ __attribute__((swift_name("SuspendBridge")))
 /**
  @note This method converts all Kotlin exceptions to errors.
 */
-- (void)nothingAsAnyValue:(id _Nullable)value completionHandler:(void (^)(id _Nullable, NSError * _Nullable))completionHandler __attribute__((swift_name("nothingAsAny(value:completionHandler:)")));
+- (void)nothingAsAnyValue:(id _Nullable)value completionHandler:(void (^)(id _Nullable_result, NSError * _Nullable))completionHandler __attribute__((swift_name("nothingAsAny(value:completionHandler:)")));
 
 /**
  @note This method converts all Kotlin exceptions to errors.
@@ -275,13 +275,13 @@ __attribute__((swift_name("CoroutinesKt")))
  @note This method converts instances of CoroutineException, CancellationException to errors.
  Other uncaught Kotlin exceptions are fatal.
 */
-+ (void)suspendFunResult:(id _Nullable)result doSuspend:(BOOL)doSuspend doThrow:(BOOL)doThrow completionHandler:(void (^)(id _Nullable, NSError * _Nullable))completionHandler __attribute__((swift_name("suspendFun(result:doSuspend:doThrow:completionHandler:)")));
++ (void)suspendFunResult:(id _Nullable)result doSuspend:(BOOL)doSuspend doThrow:(BOOL)doThrow completionHandler:(void (^)(id _Nullable_result, NSError * _Nullable))completionHandler __attribute__((swift_name("suspendFun(result:doSuspend:doThrow:completionHandler:)")));
 
 /**
  @note This method converts instances of CoroutineException, CancellationException to errors.
  Other uncaught Kotlin exceptions are fatal.
 */
-+ (void)suspendFunAsyncResult:(id _Nullable)result continuationHolder:(KtContinuationHolder<id> *)continuationHolder completionHandler:(void (^)(id _Nullable, NSError * _Nullable))completionHandler __attribute__((swift_name("suspendFunAsync(result:continuationHolder:completionHandler:)")));
++ (void)suspendFunAsyncResult:(id _Nullable)result continuationHolder:(KtContinuationHolder<id> *)continuationHolder completionHandler:(void (^)(id _Nullable_result, NSError * _Nullable))completionHandler __attribute__((swift_name("suspendFunAsync(result:continuationHolder:completionHandler:)")));
 
 /**
  @note This method converts instances of CoroutineException, CancellationException to errors.
@@ -315,7 +315,7 @@ __attribute__((swift_name("CoroutinesKt")))
  @note This method converts instances of CancellationException to errors.
  Other uncaught Kotlin exceptions are fatal.
 */
-+ (void)invoke1Block:(id<KtKotlinSuspendFunction1>)block argument:(id _Nullable)argument completionHandler:(void (^)(id _Nullable, NSError * _Nullable))completionHandler __attribute__((swift_name("invoke1(block:argument:completionHandler:)")));
++ (void)invoke1Block:(id<KtKotlinSuspendFunction1>)block argument:(id _Nullable)argument completionHandler:(void (^)(id _Nullable_result, NSError * _Nullable))completionHandler __attribute__((swift_name("invoke1(block:argument:completionHandler:)")));
 @end;
 
 __attribute__((swift_name("DeallocRetainBase")))

kotlin-native/backend.native/tests/objcexport/expectedLazyNoGenerics.h

@@ -174,7 +174,7 @@ __attribute__((swift_name("SuspendBridge")))
  @note This method converts instances of CancellationException to errors.
  Other uncaught Kotlin exceptions are fatal.
 */
-- (void)intAsAnyValue:(id _Nullable)value completionHandler:(void (^)(id _Nullable, NSError * _Nullable))completionHandler __attribute__((swift_name("intAsAny(value:completionHandler:)")));
+- (void)intAsAnyValue:(id _Nullable)value completionHandler:(void (^)(id _Nullable_result, NSError * _Nullable))completionHandler __attribute__((swift_name("intAsAny(value:completionHandler:)")));
 
 /**
  @note This method converts instances of CancellationException to errors.
@@ -186,7 +186,7 @@ __attribute__((swift_name("SuspendBridge")))
  @note This method converts instances of CancellationException to errors.
  Other uncaught Kotlin exceptions are fatal.
 */
-- (void)unitAsAnyValue:(id _Nullable)value completionHandler:(void (^)(id _Nullable, NSError * _Nullable))completionHandler __attribute__((swift_name("unitAsAny(value:completionHandler:)")));
+- (void)unitAsAnyValue:(id _Nullable)value completionHandler:(void (^)(id _Nullable_result, NSError * _Nullable))completionHandler __attribute__((swift_name("unitAsAny(value:completionHandler:)")));
 
 /**
  @note This method converts all Kotlin exceptions to errors.
@@ -201,7 +201,7 @@ __attribute__((swift_name("SuspendBridge")))
 /**
  @note This method converts all Kotlin exceptions to errors.
 */
-- (void)nothingAsAnyValue:(id _Nullable)value completionHandler:(void (^)(id _Nullable, NSError * _Nullable))completionHandler __attribute__((swift_name("nothingAsAny(value:completionHandler:)")));
+- (void)nothingAsAnyValue:(id _Nullable)value completionHandler:(void (^)(id _Nullable_result, NSError * _Nullable))completionHandler __attribute__((swift_name("nothingAsAny(value:completionHandler:)")));
 
 /**
  @note This method converts all Kotlin exceptions to errors.
@@ -275,13 +275,13 @@ __attribute__((swift_name("CoroutinesKt")))
  @note This method converts instances of CoroutineException, CancellationException to errors.
  Other uncaught Kotlin exceptions are fatal.
 */
-+ (void)suspendFunResult:(id _Nullable)result doSuspend:(BOOL)doSuspend doThrow:(BOOL)doThrow completionHandler:(void (^)(id _Nullable, NSError * _Nullable))completionHandler __attribute__((swift_name("suspendFun(result:doSuspend:doThrow:completionHandler:)")));
++ (void)suspendFunResult:(id _Nullable)result doSuspend:(BOOL)doSuspend doThrow:(BOOL)doThrow completionHandler:(void (^)(id _Nullable_result, NSError * _Nullable))completionHandler __attribute__((swift_name("suspendFun(result:doSuspend:doThrow:completionHandler:)")));
 
 /**
  @note This method converts instances of CoroutineException, CancellationException to errors.
  Other uncaught Kotlin exceptions are fatal.
 */
-+ (void)suspendFunAsyncResult:(id _Nullable)result continuationHolder:(KtContinuationHolder *)continuationHolder completionHandler:(void (^)(id _Nullable, NSError * _Nullable))completionHandler __attribute__((swift_name("suspendFunAsync(result:continuationHolder:completionHandler:)")));
++ (void)suspendFunAsyncResult:(id _Nullable)result continuationHolder:(KtContinuationHolder *)continuationHolder completionHandler:(void (^)(id _Nullable_result, NSError * _Nullable))completionHandler __attribute__((swift_name("suspendFunAsync(result:continuationHolder:completionHandler:)")));
 
 /**
  @note This method converts instances of CoroutineException, CancellationException to errors.
@@ -315,7 +315,7 @@ __attribute__((swift_name("CoroutinesKt")))
  @note This method converts instances of CancellationException to errors.
  Other uncaught Kotlin exceptions are fatal.
 */
-+ (void)invoke1Block:(id<KtKotlinSuspendFunction1>)block argument:(id _Nullable)argument completionHandler:(void (^)(id _Nullable, NSError * _Nullable))completionHandler __attribute__((swift_name("invoke1(block:argument:completionHandler:)")));
++ (void)invoke1Block:(id<KtKotlinSuspendFunction1>)block argument:(id _Nullable)argument completionHandler:(void (^)(id _Nullable_result, NSError * _Nullable))completionHandler __attribute__((swift_name("invoke1(block:argument:completionHandler:)")));
 @end;
 
 __attribute__((swift_name("DeallocRetainBase")))