add 0 length guard in IsNonArrayIndexInteger

src/conversions.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <limits.h>
 #include <stdarg.h>
 #include <cmath>
 
 #include "src/v8.h"
 
@@ skipping 491 matching lines @@
   }
 }
 
 
 bool IsNonArrayIndexInteger(String* string) {
   const int kBufferSize = 64;
   const int kUint32MaxChars = 11;
   uint16_t buffer[kBufferSize];
   int offset = 0;
   const int length = string->length();
-  DCHECK_NE(0, length);
+  if (length == 0) return false;
   // First iteration, check for minus, 0 followed by anything else, etc.
   int to = std::min(offset + kUint32MaxChars, length);
   {
     String::WriteToFlat(string, buffer, offset, to);
     bool negative = false;
     if (buffer[offset] == '-') {
       negative = true;
       ++offset;
       if (offset == to) return false;  // Just '-' is bad.
     }
@@ skipping 24 matching lines @@
     }
     if (offset == length) break;
     // Read next chunk.
     to = std::min(offset + kBufferSize, length);
     String::WriteToFlat(string, buffer, offset, to);
     i = 0;
   }
   return true;
 }
 } }  // namespace v8::internal