INTF: Fix check if interface exists (#4759)

As mentioned in #4673, the existence check for interfaces is not correct and actually checking for classes. The PR will correct the check.

Co-authored-by: Lars Hvam <larshp@hotmail.com>

src/objects/oo/zcl_abapgit_oo_base.clas.abap

@@ -81,17 +81,7 @@ CLASS zcl_abapgit_oo_base IMPLEMENTATION.
 
 
   METHOD zif_abapgit_oo_object_fnc~exists.
-    CALL FUNCTION 'SEO_CLASS_EXISTENCE_CHECK'
+    ASSERT 0 = 1. "Subclass responsibility
-      EXPORTING
-        clskey        = is_object_name
-      EXCEPTIONS
-        not_specified = 1
-        not_existing  = 2
-        is_interface  = 3
-        no_text       = 4
-        inconsistent  = 5
-        OTHERS        = 6.
-    rv_exists = boolc( sy-subrc <> 2 ).
   ENDMETHOD.
 
 

src/objects/oo/zcl_abapgit_oo_interface.clas.abap

@@ -15,6 +15,8 @@ CLASS zcl_abapgit_oo_interface DEFINITION
         REDEFINITION .
     METHODS zif_abapgit_oo_object_fnc~deserialize_source
         REDEFINITION .
+    METHODS zif_abapgit_oo_object_fnc~exists
+        REDEFINITION .
   PROTECTED SECTION.
   PRIVATE SECTION.
 
@@ -257,6 +259,21 @@ CLASS zcl_abapgit_oo_interface IMPLEMENTATION.
   ENDMETHOD.
 
 
+  METHOD zif_abapgit_oo_object_fnc~exists.
+    CALL FUNCTION 'SEO_INTERFACE_EXISTENCE_CHECK'
+      EXPORTING
+        intkey        = is_object_name
+      EXCEPTIONS
+        not_specified = 1
+        not_existing  = 2
+        is_class      = 3
+        no_text       = 4
+        inconsistent  = 5
+        OTHERS        = 6.
+    rv_exists = boolc( sy-subrc = 0 OR sy-subrc = 4 ).
+  ENDMETHOD.
+
+
   METHOD zif_abapgit_oo_object_fnc~get_includes.
     DATA lv_interface_name TYPE seoclsname.
     lv_interface_name = iv_object_name.