return type err from PyUnicode_Tailmatch if arg not string

Author: tomasstupka

graalpython/com.oracle.graal.python.test/src/tests/cpyext/test_unicode.py

@@ -132,7 +132,10 @@ def _reference_as_unicode_escape_string(args):
 
 def _reference_tailmatch(args):
     if not isinstance(args[0], str) or not isinstance(args[1], str):
-        return -1;
+        if sys.version_info.minor >= 6:
+            raise SystemError
+        else:
+            raise TypeError
 
     s = args[0]
     substr = args[1]
@@ -580,7 +583,7 @@ def compile_module(self, name):
             ("abc", 1, 1, 0, 1),
         ),
         resultspec="i",
-        argspec='OOiii',
+        argspec='OOnni',
         arguments=["PyObject* left", "PyObject* right", "Py_ssize_t start", "Py_ssize_t end", "int direction"],
         cmpfunc=unhandled_error_compare
     )

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/PythonCextBuiltins.java

@@ -3427,8 +3427,9 @@ public int tailmatch(VirtualFrame frame, Object string, Object substring, long s
         @Specialization(guards = {"!isAnyString(frame, string, getClassNode, isSubtypeNode) || !isAnyString(frame, substring, getClassNode, isSubtypeNode)"})
         public Object find(VirtualFrame frame, Object string, Object substring, Object start, Object end, Object direction,
                         @Cached GetClassNode getClassNode,
-                        @Cached IsSubtypeNode isSubtypeNode) {
-            return -1;
+                        @Cached IsSubtypeNode isSubtypeNode,
+                        @Cached PRaiseNativeNode raiseNativeNode) {
+            return raiseNativeNode.raiseInt(frame, -1, TypeError, ErrorMessages.MUST_BE_STR_NOT_P, string);
         }
 
         protected boolean isAnyString(VirtualFrame frame, Object obj, GetClassNode getClassNode, IsSubtypeNode isSubtypeNode) {