Re: [PATCH] fall back to glibc matcher if a MBCSET is found

[Paolo Bonzini]

On 09/12/2010 02:55 PM, Jim Meyering wrote:
> > Regarding the failing test-case, the lack of equivalence class support
> > is in glibc.  Should I commit the patch without the testcase?
>
> ??  Keep the test, of course.
> It's alerting us to a legitimate problem.
> We don't want to sweep that under the rug.

I thought it's was just an incomplete locale definition, which would be 
legitimate and not really a bug per se.

However, this program passes for me with glibc-2.5-42.el5:

#include <regex.h>
#include <locale.h>
#include <stdio.h>
int main()
{
        regex_t reg;

        setlocale (LC_ALL, "en_US.UTF-8");
        regcomp (&reg, "[[=a=]]", REG_NOSUB);
        if (regexec(&reg, "\xc3\xa0", 0, NULL, 0) == REG_NOMATCH)
                printf ("Equivalence classes fail\n");
        else
                printf ("Equivalence classes work\n");
}

Can you test it as well on your system?

> This is a strong argument against using --without-included-regex,
> unless you know you're using a new-enough glibc.

Why?  Note that the test is unconditionally XFAILed unless you use 
--without-included-regex.

> Your NEWS addition recommends --without-included-regex unconditionally.

I committed now my gnulib patch to m4/regex.m4, which required editing 
the NEWS entry anyway.  See the attached updated 3-patch series.

> Finally, since this change induces a performance penalty on at
> least one system, please adjust or remove this comment in the commit log.

It's a 3-4% performance penalty on one system, versus a 30% gain on more 
recent ones, so I'll make the performance comment less marked but I 
still think it should be there.  Again, see the attachment.

Paolo

regex-2.patch
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