From dc361af48bc9a1353b10b39997bb806b48f51656 Mon Sep 17 00:00:00 2001
From: "K. Lange" <klange@toaruos.org>
Date: Fri, 2 Apr 2021 12:25:07 +0900
Subject: [PATCH] Fix incorrect binding of classmethod when called on instance
 of subclass

---
 src/vm.c                                 |  5 +++--
 test/testClassMethodInherited.krk        | 10 ++++++++++
 test/testClassMethodInherited.krk.expect |  4 ++++
 3 files changed, 17 insertions(+), 2 deletions(-)
 create mode 100644 test/testClassMethodInherited.krk
 create mode 100644 test/testClassMethodInherited.krk.expect

diff --git a/src/vm.c b/src/vm.c
index aacd817..4e07647 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -910,6 +910,7 @@ KrkValue krk_callSimple(KrkValue value, int argCount, int isMethod) {
  * Works for managed and native method calls.
  */
 int krk_bindMethod(KrkClass * _class, KrkString * name) {
+	KrkClass * originalClass = _class;
 	KrkValue method, out;
 	while (_class) {
 		if (krk_tableGet_fast(&_class->methods, name, &method)) break;
@@ -920,7 +921,7 @@ int krk_bindMethod(KrkClass * _class, KrkString * name) {
 		if (((KrkNative*)AS_OBJECT(method))->flags & KRK_NATIVE_FLAGS_IS_DYNAMIC_PROPERTY) {
 			out = AS_NATIVE(method)->function(1, (KrkValue[]){krk_peek(0)}, 0);
 		} else if (((KrkNative*)AS_OBJECT(method))->flags & KRK_NATIVE_FLAGS_IS_CLASS_METHOD) {
-			out = OBJECT_VAL(krk_newBoundMethod(OBJECT_VAL(_class), AS_OBJECT(method)));
+			out = OBJECT_VAL(krk_newBoundMethod(OBJECT_VAL(originalClass), AS_OBJECT(method)));
 		} else if (((KrkNative*)AS_OBJECT(method))->flags & KRK_NATIVE_FLAGS_IS_STATIC_METHOD) {
 			out = method;
 		} else {
@@ -928,7 +929,7 @@ int krk_bindMethod(KrkClass * _class, KrkString * name) {
 		}
 	} else if (IS_CLOSURE(method)) {
 		if (AS_CLOSURE(method)->flags & KRK_FUNCTION_FLAGS_IS_CLASS_METHOD) {
-			out = OBJECT_VAL(krk_newBoundMethod(OBJECT_VAL(_class), AS_OBJECT(method)));
+			out = OBJECT_VAL(krk_newBoundMethod(OBJECT_VAL(originalClass), AS_OBJECT(method)));
 		} else if (AS_CLOSURE(method)->flags & KRK_FUNCTION_FLAGS_IS_STATIC_METHOD) {
 			out = method;
 		} else {
diff --git a/test/testClassMethodInherited.krk b/test/testClassMethodInherited.krk
new file mode 100644
index 0000000..bc57f87
--- /dev/null
+++ b/test/testClassMethodInherited.krk
@@ -0,0 +1,10 @@
+class Foo:
+    @classmethod
+    def doThing(cls):
+        print("Called from a",cls)
+class Bar(Foo):
+    pass
+Foo.doThing()
+Foo().doThing()
+Bar.doThing()
+Bar().doThing()
diff --git a/test/testClassMethodInherited.krk.expect b/test/testClassMethodInherited.krk.expect
new file mode 100644
index 0000000..1a90b5e
--- /dev/null
+++ b/test/testClassMethodInherited.krk.expect
@@ -0,0 +1,4 @@
+Called from a <class '__main__.Foo'>
+Called from a <class '__main__.Foo'>
+Called from a <class '__main__.Bar'>
+Called from a <class '__main__.Bar'>