[GR-9754] ValueError should be raised, if a list is modified during calling sort method.

PullRequest: graalpython-open/41

Author: ppisl

graalpython/com.oracle.graal.python.test/src/tests/list_tests.py

@@ -8,7 +8,7 @@
 
 import sys
 import os
-#from functools import cmp_to_key
+from functools import cmp_to_key
 import seq_tests
 #from test import support
 
@@ -489,8 +489,6 @@ def test_copy(self):
 
         self.assertRaises(TypeError, u.copy, None)
 
-    # TODO cmp_to_key is not available yet
-    '''
     def test_sort(self):
         u = self.type2test([1, 0])
         u.sort()
@@ -538,7 +536,6 @@ def selfmodifyingComparison(x,y):
                           key=cmp_to_key(selfmodifyingComparison))
 
         self.assertRaises(TypeError, z.sort, 42, 42, 42, 42)
-    '''
 
     def test_slice(self):
         u = self.type2test("spam")

graalpython/lib-graalpython/list.py

@@ -54,7 +54,10 @@ def sort(self, key=None, reverse=False):
             lt = lambda a,b: key(a) < key(b)
         else:
             lt = lambda a,b: a < b
+    origLen = len(self)
     TimSort(self, lt=lt).sort()
+    if(origLen != len(self)):
+        raise ValueError("list modified during sort")
     return None