Throw when a holey property is set in Array.sort

test/mjsunit/array-sort.js

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 462 matching lines @@
 
   {
     function f() { return arguments };
     var a = f(2,1,3);
     a.__proto__ = new Proxy({}, {});
     assertEquals([1,2,3], [...(Array.prototype.sort.apply(a))]);
   }
 }
 TestSortOnProxy();
 
+function TestSortOnNonExtensible() {
+  {
+    var arr = [1,,2];
+    Object.preventExtensions(arr);
+    var exception = false;
+    try {
+      arr.sort();
+    } catch (e) {
+      exception = true;
+      assertTrue(e instanceof TypeError);
+    }
+    assertTrue(exception);
+    assertEquals(arr, [1,,2]);
+  }
+  {
+    var arr = [1,undefined,2];
+    Object.preventExtensions(arr);
+    arr.sort();
+    assertEquals(3, arr.length);
+    assertEquals(arr, [1,2,undefined]);

[adamk, 2017/02/01 16:39:13]

Shouldn't this fail now?

[Choongwoo Han, 2017/02/01 18:21:07]

Yes. In this case, this arr does not have any hole since undefined also has a
key ([1, undefined, 2].hasOwnProperty(1) == true). 

+  }
+}
+TestSortOnNonExtensible();
+
 
 // Test special prototypes
 (function testSortSpecialPrototypes() {
   function test(proto, length, expected) {
     var result = {
        length: length,
        __proto__: proto,
      };
     Array.prototype.sort.call(result);
     assertEquals(expected.length, result.length, "result.length");
@@ skipping 44 matching lines @@
     var array = new Int32Array(3);
     array[0] = 2;
     array[1] = 1;
     array[2] = 3;
     test(array, 1, [2]);
     test(array, 2, [1, 2]);
     test(array, 3, [1, 2, 3]);
   })()
 
 })();