[Bug c/83959] New: Missing buffer overflow warning on printf %s

[prathamesh3492 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83959

            Bug ID: 83959
           Summary: Missing buffer overflow warning on printf %s
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: prathamesh3492 at gcc dot gnu.org
  Target Milestone: ---

int main(void)
{
  char a[3] = "xyz";
  __builtin_printf ("%s", a);
  return 0;
}

No warning generated with -Wall -Wextra -Wstringop-overflow=2.
Should -Wstringop-overflow be catching this case ?

I wonder if the compiler should warn (with Wextra maybe?) for
char a[3] = "xyz";
ie when sizeof(array) == strlen(initializier) ?

Although the above initializer doesn't cause overflow by itself, I suppose
almost
all string functions expect char arrays to end with '\0' and would end up
looking past end of array thus causing overflow.

Thanks,
Prathamesh