Re: [PATCH] cleanup: fix possible overflow errors in binary search

> On Fri, Oct 06, 2017 at 09:52:31AM -0400, Derrick Stolee wrote:
>
>> A common mistake when writing binary search is to allow possible
>> integer overflow by using the simple average:
>>
>> 	mid = (min + max) / 2;
>>
>> Instead, use the overflow-safe version:
>>
>> 	mid = min + (max - min) / 2;
> Great, thank you for picking this up!
>
>> The included changes were found using the following two greps:
>>
>> 	grep "/ 2;" *.c
>> 	grep "/ 2;" */*.c
>> 	grep "/2;" */*.c
> You can use[1]:
>
>    git grep '/ 2;' '*.c'
>
> to have Git expand the wildcard. That catches a few extra cases in
> compat/regex/*.c.  Even though it's imported code, it might be
> nice to cover those, too (since it's a possible bug, and also as a good
> example).
>
> [1] I'd actually write:
>
>        git grep '/ *2;' '*.c'
>
>      to do it all in one grep. :)

>> ---
>>   builtin/index-pack.c     | 4 ++--
>>   builtin/pack-objects.c   | 2 +-
>>   builtin/unpack-objects.c | 2 +-
>>   cache-tree.c             | 2 +-
>>   packfile.c               | 2 +-
>>   sha1-lookup.c            | 2 +-
>>   sha1_name.c              | 2 +-
>>   string-list.c            | 2 +-
>>   utf8.c                   | 2 +-
>>   xdiff/xpatience.c        | 2 +-
>>   10 files changed, 11 insertions(+), 11 deletions(-)
> These all look good to me (really the only way the conversion could be
> bad is if "min" was higher than "max", and each case is just inside a
> loop condition which makes sure that is not the case).
>
> -Peff