From 74cbc01a04fd7b6a092d3428ada254fdb22a762b Mon Sep 17 00:00:00 2001
From: Vladimir Ivanov <knebekaizer@users.noreply.github.com>
Date: Wed, 6 May 2020 12:08:51 +0300
Subject: [PATCH] =?UTF-8?q?Avoid=20duplicated=20selectors=20when=20Kotlin?=
 =?UTF-8?q?=20class=20inherits=20from=20muliple=20ba=E2=80=A6=20(#4145)?=
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Issue: RuntimeAssert in AddMethods (ObjCInterop.mm) when kotlin class overrides the same
selector from multiple bases, e.g. from the base objc class and a protocol(s).
---
 .../kotlin/backend/konan/lower/InteropLowering.kt      |  6 ++++--
 .../tests/interop/objc/tests/KT38234_override.h        |  9 +++++++++
 .../tests/interop/objc/tests/KT38234_override.kt       | 10 ++++++++++
 .../tests/interop/objc/tests/KT38234_override.m        | 10 ++++++++++
 4 files changed, 33 insertions(+), 2 deletions(-)
 create mode 100644 backend.native/tests/interop/objc/tests/KT38234_override.h
 create mode 100644 backend.native/tests/interop/objc/tests/KT38234_override.kt
 create mode 100644 backend.native/tests/interop/objc/tests/KT38234_override.m

diff --git a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/InteropLowering.kt b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/InteropLowering.kt
index dc237d76ed7..183ddbd285e 100644
--- a/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/InteropLowering.kt
+++ b/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/InteropLowering.kt
@@ -864,12 +864,14 @@ private class InteropTransformer(val context: Context, override val irFile: IrFi
     override fun visitClass(declaration: IrClass): IrStatement {
         super.visitClass(declaration)
         if (declaration.isKotlinObjCClass()) {
+            val uniq = mutableSetOf<String>()  // remove duplicates [KT-38234]
             val imps = declaration.simpleFunctions().filter { it.isReal }.flatMap { function ->
                 function.overriddenSymbols.mapNotNull {
-                    val info = it.owner.getExternalObjCMethodInfo()
-                    if (info == null) {
+                    val selector = it.owner.getExternalObjCMethodInfo()?.selector
+                    if (selector == null || selector in uniq) {
                         null
                     } else {
+                        uniq += selector
                         generateWithStubs(it.owner) {
                             generateCFunctionAndFakeKotlinExternalFunction(
                                     function,
diff --git a/backend.native/tests/interop/objc/tests/KT38234_override.h b/backend.native/tests/interop/objc/tests/KT38234_override.h
new file mode 100644
index 00000000000..8a1561d8513
--- /dev/null
+++ b/backend.native/tests/interop/objc/tests/KT38234_override.h
@@ -0,0 +1,9 @@
+#import <Foundation/NSObject.h>
+
+@protocol KT38234_P1
+-(int)foo;
+@end;
+
+@interface KT38234_Base : NSObject <KT38234_P1>
+-(int)callFoo;
+@end;
diff --git a/backend.native/tests/interop/objc/tests/KT38234_override.kt b/backend.native/tests/interop/objc/tests/KT38234_override.kt
new file mode 100644
index 00000000000..5e5ea4c5b1b
--- /dev/null
+++ b/backend.native/tests/interop/objc/tests/KT38234_override.kt
@@ -0,0 +1,10 @@
+import kotlin.test.*
+import objcTests.*
+
+class KT38234_Impl : KT38234_P1Protocol, KT38234_Base() {
+    override fun foo(): Int = 566
+}
+
+@Test fun testKT38234() {
+    assertEquals(566, KT38234_Impl().callFoo())
+}
diff --git a/backend.native/tests/interop/objc/tests/KT38234_override.m b/backend.native/tests/interop/objc/tests/KT38234_override.m
new file mode 100644
index 00000000000..675baa38af0
--- /dev/null
+++ b/backend.native/tests/interop/objc/tests/KT38234_override.m
@@ -0,0 +1,10 @@
+#include "KT38234_override.h"
+
+@implementation KT38234_Base
+-(int)foo {
+    return 1;
+}
+-(int)callFoo {
+    return [self foo];
+}
+@end;