Hi René, On Fri, 10 Feb 2017, René Scharfe wrote: > Am 10.02.2017 um 15:20 schrieb Johannes Schindelin: > > It is curious that only MacOSX builds trigger an error about this, both > > GCC and Clang, but not Linux GCC nor Clang (see > > https://travis-ci.org/git/git/jobs/200182819#L1152 for details): > > > > builtin/bisect--helper.c:299:6: error: variable 'good_syn' is used > > uninitialized whenever 'if' condition is true > > [-Werror,-Wsometimes-uninitialized] > > if (missing_good && !missing_bad && current_term && > > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > builtin/bisect--helper.c:350:7: note: uninitialized use occurs here > > if (!good_syn) > > ^~~~~~~~ > > The only way that good_syn could be used in the if block is by going to the > label finish, which does the following before returning: > > if (!bad_ref) > free(bad_ref); > if (!good_glob) > free(good_glob); > if (!bad_syn) > free(bad_syn); > if (!good_syn) > free(good_syn); > > On Linux that code is elided completely -- freeing NULL is a no-op. I guess > free(3) has different attributes on OS X and compilers don't dare to optimize > it away there. > > So instead of calling free(3) only in the case when we did not allocate memory > (which makes no sense and leaks) we should either call it in the opposite > case, or (preferred) unconditionally, as it can handle the NULL case itself. > Once that's fixed initialization will be required even on Linux. Exactly, free(NULL) is a no-op. The problem before this fixup was that good_syn was not initialized to NULL. Ciao, Dscho