V2.6 false positive: knownConditionTrueFalse when break out of loop.

[David Zanter]

Hello, I did see a couple of other false positives related to knownConditionTrueFalse in the Forum; However they didn't seem to be exactly the same. The following code is flagging a false positive of: knownConditionTrueFalse

This is a simplfied test program, where it looks like it is missing that the second if statement can break out and then pool != NULL.

void main ()
{
   void * pool = NULL;
   void * edp = NULL;
   do
   {
      pool = malloc(40);
      if (pool == NULL)
      {
         break;
      }
      edp = malloc(20);
      if (edp == NULL)
      {
         break;
      }

      edp->pool               = pool;
      pool                    = NULL;
   }
   while (0);

   if (pool)
     free(pool);
}

[centos@dzdocker tk-build-container]$ cppcheck --enable=all /u/dazant/docker/falsepositive.c
Checking /u/dazant/docker/falsepositive.c ...
/u/dazant/docker/falsepositive.c:25:8: style: Condition 'pool' is always false [knownConditionTrueFalse]
   if (pool)
       ^
/u/dazant/docker/falsepositive.c:21:33: note: Assignment 'pool=NULL', assigned value is 0
      pool                    = NULL;
                                ^
/u/dazant/docker/falsepositive.c:25:8: note: Condition 'pool' is always false
   if (pool)
       ^

Thanks!

[Daniel Marjamäki]

Thanks! I can reproduce. I have created https://trac.cppcheck.net/ticket/10625