Re: [PATCH/RFC] attr: allow pattern escape using backslash

2012-10-06 Thread Nguyen Thai Ngoc Duy
On Sat, Oct 6, 2012 at 2:54 PM, Junio C Hamano  wrote:
> Shouldn't we do the same for quoting fnmatch(3) metacharacters?  To
> match a path component 'a' followed by an asterisk followed by 'b',
> you could then write 'a\*b'.  Same for quoting the backslash itself.

I think my patch does that too. The thing it does not do is optimize
this case so that we can do strcmp() instead of fnmatch() if the
entire pattern does not contain any metacharacters but backslashes. I
don't think it'll become popular enough to deserve an optimization.
-- 
Duy
--
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html


Re: [PATCH/RFC] attr: allow pattern escape using backslash

2012-10-06 Thread Junio C Hamano
Nguyễn Thái Ngọc Duy   writes:

> .gitattributes pattern syntax is supposed to be the same as .gitignore
> (except a few things that do not make sense in attr context, but
> that's a different issue). .gitignore uses fnmatch() as the matching
> machinery and "\" is accepted as an escape code. In theory the pattern
> 'foo\ bar' should match path 'foo bar' in .gitignore. Granted, no one
> would write 'foo\ bar' in .gitignore when 'foo bar' should
> suffice.
>
> Regardless, 'foo\ bar attr' does not (but should) attach "attr" to
> path "foo bar" because pattern/attr parse code does not understand
> backslash escape. It parses the line as path 'foo\' and attributes
> 'bar' and 'attr'. This patch teaches attr code to recognize the
> backslash in patterns (not macro names) and pass 'foo\ bar' down to
> fnmatch().
>
> This changes the attr behavior. "foo\ attr", if exists in the field,
> would match nothing because path "foo\" is invalid in UNIX and is a
> directory in Windows, which we do not accept attaching attributes
> to. With this patch, that line becomes invalid and is rejected. So
> it's not really bad (i.e. no silent changes in behavior).
>
> Other subtle behavioral changes may happen. Still, I think we should
> do this as it seems like a correct thing to do.
>
> Signed-off-by: Nguyễn Thái Ngọc Duy 
> ---
>  We discussed the "spaces in path names in attr" before and I remember
>  using quotes or double quotes, even substituting spaces with
>  dots, were raised. I don't remember if backslashes were mentioned.

My knee-jerk reaction, without thinking things through, is that this
makes sense and doing the same for .gitignore would, too (even
though the one-item-per-line nature of .gitignore makes "\ " and " "
practically equivalent).

Shouldn't we do the same for quoting fnmatch(3) metacharacters?  To
match a path component 'a' followed by an asterisk followed by 'b',
you could then write 'a\*b'.  Same for quoting the backslash itself.
--
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html