On Wed, Oct 17, 2007 at 05:59:27PM -0700, Linus Torvalds wrote: > It happens. We do de-spacification in the kernel occasionally when it is > an annoyance. Usually it shows up in patches, though - exactly because > code which adds spaces instead of tabs won't line up correctly in the > diff. You have made this claim several times, and I really don't understand it. If I have 8 spaces, then a diff line will have either " ", "+", or "-" followed by 8 spaces. If I use a hard tab, then the tab will end up only taking up 7 spaces because of the nature of tabs. This might matter if I'm comparing non-diff code to diff code. But in a diff, _everything_ is indented by exactly one space, so it all lines up. Is there something I'm missing? > So it doesn't matter *which* one you use (all spaces or all tabs) in that > sense. Yes, I agree with that (even with an all-tabs policy, there are still mangled and incorrect patches that come in -- and the maintainer rejects or fixes them). Which was what I was trying to point out with my question (though I was also curious to hear your answer): all-space versus all-tab is largely a matter of preference. And that means that people who want git to change to _their_ preference are just being silly. > And smaller *is* faster. Do something like this on the kernel: > > GIT_PAGER= time git grep sched_fair > > and then do the same thing with the kernel sources blown up by 20% by > de-tabification. Guess which one is 20% slower? I was about to tell you that you're full of it, but there really is a slowdown: $ cd linux-2.6 $ GIT_PAGER= time git grep sched_fair >/dev/null 0.34user 0.94system 0:01.30elapsed 98%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+7548minor)pagefaults 0swaps $ find . -name .git -prune -o -type f | xargs perl -pi -e 's/\t/ /g' $ git-commit -a -m de-tabify $ git-repack -a -d $ GIT_PAGER= time git grep sched_fair >/dev/null 0.42user 1.06system 0:01.54elapsed 96%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+7591minor)pagefaults 0swaps It's actually about 16%. Gah, I can't believe I've not only been sucked into a tab vs spaces discussion, but now I've actually wasted time doing a performance comparison on it. As an aside, that commit was enough to trigger a "git-gc --auto", which was my first experience with it. It's actually kind of annoying (especially since I was about to repack -a -d). -Peff - To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
