Re: [PATCH 11/11] bug_fl(): add missing `va_end()` call

> Jeff King <peff@peff.net> writes:
>
>> On Wed, Jun 15, 2022 at 11:35:45PM +0000, Johannes Schindelin via GitGitGadget wrote:
>>
>>> From: Johannes Schindelin <johannes.schindelin@gmx.de>
>>> 
>>> According to the manual:
>>> 
>>> 	Each invocation of va_copy() must be matched by a corresponding
>>> 	invocation of va_end() in the  same function.
>>> 
>>> Note: There is another instance of `va_copy()` in `usage.c` that is
>>> missing a `va_end()` call, in `BUG_vfl()`. It does not matter there,
>>> though, because that function either `exit()`s or `abort()`s, anyway.
>>> 
>>> Reported by Coverity.
>>
>> This was introduced by the recent 0cc05b044f (usage.c: add a non-fatal
>> bug() function to go with BUG(), 2022-06-02). But there's a much worse
>> bug in the same function. The code introduced by that patch does:
>>
>>   va_list ap, cp;
>>   [...]
>>   va_copy(cp, ap);
>>   va_start(ap, fmt);
>>
>> So "cp" is copied from "ap" before we have actually initialized "ap".
>> It's surprising that this works at all. The two lines should be flipped.
>
> Yes, it is surprising.  Perhaps it is not working at all.
>
> Thanks for an extra set of eyeballs.