patch 9.1.0673: Vim9: too recursive func calls when calling super-class method

Problem:  Vim9: too recursive func calls when calling super-class method
          with non-overriden super-call methods. (Aliaksei Budavei)
Solution: use interface method, when super is to be used (Ernie Rael)

When compiling "super.Func()" force class context to class that defines
function that is doing "super.Func()".
ISN_METHODCALL arg "cmf_is_super" for specific ufunc.

fixes: #15448
fixes: #15463 (2) super.method may not execute in context of defining
                  class
closes: #15477

Signed-off-by: Ernie Rael <errael@raelity.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/proto/vim9instr.pro

@@ -58,7 +58,7 @@ int check_internal_func_args(cctx_T *cctx, int func_idx, int argcount, int metho
 int generate_BCALL(cctx_T *cctx, int func_idx, int argcount, int method_call);
 int generate_LISTAPPEND(cctx_T *cctx);
 int generate_BLOBAPPEND(cctx_T *cctx);
-int generate_CALL(cctx_T *cctx, ufunc_T *ufunc, class_T *cl, int mi, int pushed_argcount);
+int generate_CALL(cctx_T *cctx, ufunc_T *ufunc, class_T *cl, int mi, int pushed_argcount, int is_super);
 int generate_UCALL(cctx_T *cctx, char_u *name, int argcount);
 int check_func_args_from_type(cctx_T *cctx, type_T *type, int argcount, int at_top, char_u *name);
 int generate_PCALL(cctx_T *cctx, int argcount, char_u *name, type_T *type, int at_top);

src/testdir/test_vim9_class.vim

@@ -3252,6 +3252,141 @@ def Test_using_base_class()
   v9.CheckSourceSuccess(lines)
 enddef
 
+def Test_super_dispatch()
+  # See #15448 and #15463
+  var lines =<< trim END
+    vim9script
+
+    class A
+        def String(): string
+            return 'A'
+        enddef
+    endclass
+
+    class B extends A
+        def String(): string
+            return super.String()
+        enddef
+    endclass
+
+    class C extends B
+    endclass
+
+    assert_equal('A', C.new().String())
+  END
+  v9.CheckSourceSuccess(lines)
+
+  lines =<< trim END
+    vim9script
+
+    class A
+        def F(): string
+            return 'AA'
+        enddef
+    endclass
+
+    class B extends A
+        def F(): string
+            return 'BB'
+        enddef
+        def S(): string
+            return super.F()
+        enddef
+        def S0(): string
+            return this.S()
+        enddef
+    endclass
+
+    class C extends B
+        def F(): string
+            return 'CC'
+        enddef
+        def ToB(): string
+            return super.F()
+        enddef
+    endclass
+
+    assert_equal('AA', B.new().S())
+    assert_equal('AA', C.new().S())
+    assert_equal('AA', B.new().S0())
+    assert_equal('AA', C.new().S0())
+
+    assert_equal('BB', C.new().ToB())
+
+    assert_equal('CC', C.new().F())
+    assert_equal('BB', B.new().F())
+    assert_equal('AA', A.new().F())
+  END
+  v9.CheckSourceSuccess(lines)
+
+  lines =<< trim END
+    vim9script
+
+    var call_chain: list<string>
+
+    abstract class A
+        abstract def _G(): string
+
+        def F(): string
+            call_chain->add('A.F()')
+            return this._G()
+        enddef
+        def _H(): string
+            call_chain->add('A._H()')
+            return this.F()
+        enddef
+    endclass
+
+    class B extends A
+        def _G(): string
+            call_chain->add('B.G()')
+            return 'BBB'
+        enddef
+        def SF(): string
+            call_chain->add('B.SF()')
+            return super._H()
+        enddef
+    endclass
+
+    class C extends B
+    endclass
+
+    class D extends C
+        def SF(): string
+            call_chain->add('D.SF()')
+            return super.SF()
+        enddef
+    endclass
+
+    class E extends D
+        def SF(): string
+            call_chain->add('E.SF()')
+            return super.SF()
+        enddef
+    endclass
+
+    class F extends E
+        def _G(): string
+            call_chain->add('F._G()')
+            return 'FFF'
+        enddef
+    endclass
+
+    # E.new() -> A.F() -> B._G()
+    call_chain = []
+    var o1 = E.new()
+    assert_equal('BBB', o1.F())
+    assert_equal(['A.F()', 'B.G()'], call_chain)
+
+    # F.new() -> E.SF() -> D.SF() -> B.SF() -> A._H() -> A.F() -> F._G()
+    call_chain = []
+    var o2 = F.new()
+    assert_equal('FFF', o2.SF())
+    assert_equal(['E.SF()', 'D.SF()', 'B.SF()', 'A._H()', 'A.F()', 'F._G()'], call_chain)
+  END
+  v9.CheckSourceSuccess(lines)
+enddef
+
 def Test_class_import()
   var lines =<< trim END
     vim9script

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    673,
 /**/
     672,
 /**/

src/vim9.h

@@ -238,8 +238,9 @@ typedef struct {
 // arguments to ISN_METHODCALL
 typedef struct {
     class_T *cmf_itf;	    // interface used
-    int	    cmf_idx;	    // index in "def_functions" for ISN_DCALL
+    int	    cmf_idx;	    // index in "def_functions" for ISN_METHODCALL
     int	    cmf_argcount;   // number of arguments on top of stack
+    int	    cmf_is_super;   // doing "super.Func", use cmf_itf, not cmf_idx
 } cmfunc_T;
 
 // arguments to ISN_PCALL

src/vim9execute.c

@@ -4400,14 +4400,23 @@ exec_instructions(ectx_T *ectx)
 			goto on_error;
 		    }
 
+		    ufunc_T *ufunc;
+		    if (mfunc->cmf_is_super)
+			// Doing "super.Func", use the specific ufunc.
+			ufunc = mfunc->cmf_itf->class_obj_methods[
+							    mfunc->cmf_idx];
+		    else
+		    {
 			class_T *cl = obj->obj_class;
 
 			// convert the interface index to the object index
 			int idx = object_index_from_itf_index(mfunc->cmf_itf,
 						     TRUE, mfunc->cmf_idx, cl);
+			ufunc = cl->class_obj_methods[idx];
+		    }
 
-		    if (call_ufunc(cl->class_obj_methods[idx], NULL,
-				mfunc->cmf_argcount, ectx, NULL, NULL) == FAIL)
+		    if (call_ufunc(ufunc, NULL, mfunc->cmf_argcount, ectx,
+							   NULL, NULL) == FAIL)
 			goto on_error;
 		}
 		break;

src/vim9expr.c

@@ -349,6 +349,11 @@ compile_class_object_index(cctx_T *cctx, char_u **arg, type_T *type)
 	else
 	{
 	    // type->tt_type == VAR_OBJECT: method call
+	    // When compiling Func and doing "super.SomeFunc()", must be in the
+	    // class context that defines Func.
+	    if (is_super)
+		cl = cctx->ctx_ufunc->uf_defclass;
+
 	    function_count = cl->class_obj_method_count;
 	    child_count = cl->class_obj_method_count_child;
 	    functions = cl->class_obj_methods;
@@ -419,8 +424,8 @@ compile_class_object_index(cctx_T *cctx, char_u **arg, type_T *type)
 	    return generate_PCALL(cctx, argcount, name, ocm->ocm_type, TRUE);
 	if (type->tt_type == VAR_OBJECT
 		     && (cl->class_flags & (CLASS_INTERFACE | CLASS_EXTENDED)))
-	    return generate_CALL(cctx, ufunc, cl, fi, argcount);
-	return generate_CALL(cctx, ufunc, NULL, 0, argcount);
+	    return generate_CALL(cctx, ufunc, cl, fi, argcount, is_super);
+	return generate_CALL(cctx, ufunc, NULL, 0, argcount, FALSE);
     }
 
     if (type->tt_type == VAR_OBJECT)
@@ -1035,7 +1040,7 @@ compile_builtin_method_call(cctx_T *cctx, class_builtin_T builtin_method)
 	ufunc_T *uf = class_get_builtin_method(type->tt_class, builtin_method,
 							&method_idx);
 	if (uf != NULL)
-	    res = generate_CALL(cctx, uf, type->tt_class, method_idx, 0);
+	    res = generate_CALL(cctx, uf, type->tt_class, method_idx, 0, FALSE);
     }
 
     return res;
@@ -1238,7 +1243,7 @@ compile_call(
 	{
 	    if (!func_is_global(ufunc))
 	    {
-		res = generate_CALL(cctx, ufunc, NULL, 0, argcount);
+		res = generate_CALL(cctx, ufunc, NULL, 0, argcount, FALSE);
 		goto theend;
 	    }
 	    if (!has_g_namespace
@@ -1257,7 +1262,7 @@ compile_call(
 	    if (cctx->ctx_ufunc->uf_defclass == cl)
 	    {
 		res = generate_CALL(cctx, cl->class_class_functions[mi], NULL,
-							0, argcount);
+							0, argcount, FALSE);
 	    }
 	    else
 	    {
@@ -1285,7 +1290,7 @@ compile_call(
     // If we can find a global function by name generate the right call.
     if (ufunc != NULL)
     {
-	res = generate_CALL(cctx, ufunc, NULL, 0, argcount);
+	res = generate_CALL(cctx, ufunc, NULL, 0, argcount, FALSE);
 	goto theend;
     }
 

src/vim9instr.c

@@ -1805,6 +1805,8 @@ generate_BLOBAPPEND(cctx_T *cctx)
  * Generate an ISN_DCALL, ISN_UCALL or ISN_METHODCALL instruction.
  * When calling a method on an object, of which we know the interface only,
  * then "cl" is the interface and "mi" the method index on the interface.
+ * save is_super in the "isn->isn_arg"; it flags execution to use mfunc
+ * directly to determine ufunc.
  * Return FAIL if the number of arguments is wrong.
  */
     int
@@ -1813,7 +1815,8 @@ generate_CALL(
 	ufunc_T	    *ufunc,
 	class_T	    *cl,
 	int	    mi,
-	int	    pushed_argcount)
+	int	    pushed_argcount,
+	int	    is_super)
 {
     isn_T	*isn;
     int		regular_args = ufunc->uf_args.ga_len;
@@ -1898,6 +1901,7 @@ generate_CALL(
 	++cl->class_refcount;
 	isn->isn_arg.mfunc->cmf_idx = mi;
 	isn->isn_arg.mfunc->cmf_argcount = argcount;
+	isn->isn_arg.mfunc->cmf_is_super = is_super;
     }
     else if (isn->isn_type == ISN_DCALL)
     {