Fix bug in deletion of indexed properties

The delete operator always return true in case of indexed property. It
should return false if an indexed property can't be deleted (eg.
DontDelete attribute is set or a string object is the holder).

Contributed by Peter Varga <pvarga@inf.u-szeged.hu>

BUG=none
TEST=mjsunit/delete-non-configurable

Review URL: https://codereview.chromium.org/11094021
Patch from Peter Varga <pvarga@inf.u-szeged.hu>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12736 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/elements.cc

@@ -1336,30 +1336,29 @@ class DictionaryElementsAccessor
     int entry = dictionary->FindEntry(key);
     if (entry != SeededNumberDictionary::kNotFound) {
       Object* result = dictionary->DeleteProperty(entry, mode);
-      if (result == heap->true_value()) {
-        MaybeObject* maybe_elements = dictionary->Shrink(key);
-        FixedArray* new_elements = NULL;
-        if (!maybe_elements->To(&new_elements)) {
-          return maybe_elements;
-        }
-        if (is_arguments) {
-          FixedArray::cast(obj->elements())->set(1, new_elements);
-        } else {
-          obj->set_elements(new_elements);
+      if (result == heap->false_value()) {
+        if (mode == JSObject::STRICT_DELETION) {
+          // Deleting a non-configurable property in strict mode.
+          HandleScope scope(isolate);
+          Handle<Object> holder(obj);
+          Handle<Object> name = isolate->factory()->NewNumberFromUint(key);
+          Handle<Object> args[2] = { name, holder };
+          Handle<Object> error =
+              isolate->factory()->NewTypeError("strict_delete_property",
+                                               HandleVector(args, 2));
+          return isolate->Throw(*error);
         }
+        return heap->false_value();
       }
-      if (mode == JSObject::STRICT_DELETION &&
-          result == heap->false_value()) {
-        // In strict mode, attempting to delete a non-configurable property
-        // throws an exception.
-        HandleScope scope(isolate);
-        Handle<Object> holder(obj);
-        Handle<Object> name = isolate->factory()->NewNumberFromUint(key);
-        Handle<Object> args[2] = { name, holder };
-        Handle<Object> error =
-            isolate->factory()->NewTypeError("strict_delete_property",
-                                             HandleVector(args, 2));
-        return isolate->Throw(*error);
+      MaybeObject* maybe_elements = dictionary->Shrink(key);
+      FixedArray* new_elements = NULL;
+      if (!maybe_elements->To(&new_elements)) {
+        return maybe_elements;
+      }
+      if (is_arguments) {
+        FixedArray::cast(obj->elements())->set(1, new_elements);
+      } else {
+        obj->set_elements(new_elements);
       }
     }
     return heap->true_value();

src/objects.cc

@@ -3904,6 +3904,21 @@ MaybeObject* JSObject::DeleteElement(uint32_t index, DeleteMode mode) {
     return isolate->heap()->false_value();
   }
 
+  if (IsStringObjectWithCharacterAt(index)) {
+    if (mode == STRICT_DELETION) {
+      // Deleting a non-configurable property in strict mode.
+      HandleScope scope(isolate);
+      Handle<Object> holder(this);
+      Handle<Object> name = isolate->factory()->NewNumberFromUint(index);
+      Handle<Object> args[2] = { name, holder };
+      Handle<Object> error =
+          isolate->factory()->NewTypeError("strict_delete_property",
+                                           HandleVector(args, 2));
+      return isolate->Throw(*error);
+    }
+    return isolate->heap()->false_value();
+  }
+
   if (IsJSGlobalProxy()) {
     Object* proto = GetPrototype();
     if (proto->IsNull()) return isolate->heap()->false_value();

test/mjsunit/delete-non-configurable.js

+// Copyright 2012 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
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Delete elements of a String object.
+var TIPLI = "tipli"
+var so = new String(TIPLI);
+var length = so.length;
+
+for (var i = 0; i < length; i++) {
+  assertFalse(delete so[i]);
+  assertThrows("'use strict'; delete so[i];", TypeError);
+  assertFalse(delete so[i.toString()]);
+  assertThrows("'use strict'; delete so[i.toString()];", TypeError);
+}
+
+assertEquals(length, so.length);
+assertEquals(new String(TIPLI), so);
+
+// Delete elements of an Array.
+var arr = new Array(length);
+
+for (var i = 0; i < length; i++) {
+  arr[i] = i;
+  Object.defineProperty(arr, i, { configurable: false });
+}
+
+for (var i = 0; i < length; i++) {
+  assertFalse(delete arr[i]);
+  assertThrows("'use strict'; delete arr[i];", TypeError);
+  assertFalse(delete arr[i.toString()]);
+  assertThrows("'use strict'; delete arr[i.toString()];", TypeError);
+  assertEquals(i, arr[i]);
+}
+
+assertEquals(length, arr.length);
+assertTrue(delete arr[length]);
+
+// Delete an element of an Object.
+var INDEX = 28;
+var obj = new Object();
+
+obj[INDEX] = TIPLI;
+Object.defineProperty(obj, INDEX, { configurable: false });
+
+assertFalse(delete obj[INDEX]);
+assertThrows("'use strict'; delete obj[INDEX];", TypeError);
+assertFalse(delete obj[INDEX.toString()]);
+assertThrows("'use strict'; delete obj[INDEX.toString()];", TypeError);
+assertEquals(TIPLI, obj[INDEX]);
+assertTrue(delete arr[INDEX+1]);