Re: [PATCH nd/wildmatch] Correct Git's version of isprint and isspace

From: René Scharfe <rene.scharfe@lsrfire.ath.cx>
Date: Nov 14, 2012, 19:30 UTC
Message-ID: <50A3F15C.7000200@lsrfire.ath.cx>
In-Reply-To: <CA+55aFynRG-CbSp-aLoo1iZTvfBWMgt6kwrPiQjSZJ0ZzraDKQ@mail.gmail.com>

Am 13.11.2012 20:50, schrieb Linus Torvalds:

Show 17 quoted lines

> On Tue, Nov 13, 2012 at 11:40 AM, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
>>
>> I have to wonder why you care? As far as I'm concerned, the only valid
>> space is space, TAB and CR/LF.
>>
>> Anything else is *noise*, not space. What's the reason for even caring?
>
> Btw, expanding the whitespace selection may actually be very
> counter-productive. It is used primarily for things like removing
> extraneous space at the end of lines etc, and for that, the current
> selection of SPACE, TAB and LF/CR is the right thing to do.
>
> Adding things like FF etc - that are *technically* whitespace, but
> aren't the normal kind of silent whitespace - is potentially going to
> change things too much. People might *want* a form-feed in their
> messages, for all we know.

The patch was motivated by the integration of the wildmatch library, which exposes named character classes to users. It replaces a call of fnmatch in match_pathname. Users probably expect [:space:] to mean the same in git as in other programs.

I never saw a vertical tab and I can't imagine what it's used for. I'd expect form-feeds to be matched as space, though. Didn't see them very often, admittedly.

Nevertheless, it's unfortunate that we have an isspace() that *almost* does what the widely known thing of the same name does. I'd shy away from changing git's version directly, because it's used more than a hundred times in the code, and estimating the impact of adding \v and \f to it. Perhaps renaming it to isgitspace() is a good first step, followed by adding a "standard" version of isspace() for wildmatch?

René