add 0 length guard in IsNonArrayIndexInteger

test/cctest/test-conversions.cc

 // Copyright 2011 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 356 matching lines @@
 static void CheckNonArrayIndex(bool expected, const char* chars) {
   auto isolate = CcTest::i_isolate();
   auto string = isolate->factory()->NewStringFromAsciiChecked(chars);
   CHECK_EQ(expected, IsNonArrayIndexInteger(*string));
 }
 
 
 TEST(NonArrayIndexParsing) {
   auto isolate = CcTest::i_isolate();
   HandleScope scope(isolate);
+  CheckNonArrayIndex(false, "");
   CheckNonArrayIndex(false, "-");
   CheckNonArrayIndex(false, "0");
   CheckNonArrayIndex(false, "01");
   CheckNonArrayIndex(false, "-01");
   CheckNonArrayIndex(false, "4294967295");
   CheckNonArrayIndex(false, "429496.7295");
   CheckNonArrayIndex(false, "43s3");
   CheckNonArrayIndex(true, "-0");
   CheckNonArrayIndex(true, "-1");
   CheckNonArrayIndex(true, "4294967296");
@@ skipping 22 matching lines @@
       "429496729642949672964294967296429496729642949672964294967296"
       "429496729642949672964294967296429496729642949672964294967296"
       "429496729642949672964294967296429496729642949672964294967296"
       "429496729642949672964294967296429496729642949672964294967296"
       "429496729642949672964294967296429496729642949672964294967296"
       "429496729642949672964294967296429496729642949672964294967296"
       "429496729642949672964294967296429496729642949672964294967296"
       "429496729642949672964294967296429496729642949672964294967296"
       "429496729642949672964294967296429496729642949672964294967296");
 }