[Bug tree-optimization/104746] [12 Regression] False positive for -Wformat-overflow=2 since r12-7033-g3c9f762ad02f398c

[marxin at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104746

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |NEW
         Resolution|INVALID                     |---

--- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> ---
> That said, the warning persists even with a buffer of sufficient size, but
> then disappears if the empty definition of systemd_escape2() is removed. 
> Since the function fails to return a result the test case is invalid, I'm
> guessing because it was reduced too far.  Can you provide a valid test case?
> 

Sure, there's a valid test-case that is completely fine and we emit a warning:

$ cat problem.c
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
  const char *pipefs_path = argv[1];
  const char *dirname = argv[1];
  const char *suffix = ".mount";

  int len = strlen(pipefs_path);
  char *result = malloc(len + strlen(suffix) + 1);
  sprintf(result, "%s", suffix);

  char *path = malloc(strlen(dirname) + strlen(result) + 2);
  sprintf(path, "%s/%s", dirname, result);

  return 0;
}