Use flag name without 'no' prefix only if it exists

webrtc/rtc_base/flags.cc

 /*
  *  Copyright 2006 The WebRTC 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 in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 131 matching lines @@
                              bool* is_bool) {
   *name = nullptr;
   *value = nullptr;
   *is_bool = false;
 
   if (*arg == '-') {
     // find the begin of the flag name
     arg++;  // remove 1st '-'
     if (*arg == '-')
       arg++;  // remove 2nd '-'
-    if (arg[0] == 'n' && arg[1] == 'o') {
+    if (arg[0] == 'n' && arg[1] == 'o' && Lookup(arg + 2)) {
       arg += 2;  // remove "no"
       *is_bool = true;
     }

[kwiberg-webrtc, 2017/09/04 23:30:39]

Wait... what? Do we just *ignore* the "no" prefix? So that -foo and -nofoo mean
the same thing?

[oprypin_webrtc, 2017/09/05 06:54:16]

Yeah that also threw me off. This variable is more like... is_false, judging
from its usages.
I just re-checked that it works correctly.

     *name = arg;
 
     // find the end of the flag name
     while (*arg != '\0' && *arg != '=')
       arg++;
 
     // get the value if any
     if (*arg == '=') {
       // make a copy so we can NUL-terminate flag name
       int n = static_cast<int>(arg - *name);
@@ skipping 124 matching lines @@
   // need to free each string in the array, and then the array.
   for(int i = 0; i < argc_; i++) {
     delete[] argv_[i];
   }
 
   delete[] argv_;
 }
 #endif  // WEBRTC_WIN
 
 }  // namespace rtc