Re: new snapshot available: grep-3.1.46-504af

[Bruno Haible <bruno@clisp.org>]

Hi Jim,

> > I guess the fix should be to detect the glibc bug in m4/regex.m4 ?
> 
> Exactly. That's what I'm doing now.
> I'm expecting to insert something like this, probably reusing the
> result value of "64":
> 
>             /* Matching with the compiled form of this regexp would
> provoke
>                an assertion failure prior to glibc-2.28:
>                  regexec.c:1375: pop_fail_stack: Assertion `num >= 0'
> failed
>                With glibc-2.28, compilation fails and reports the
> invalid
>                back reference.  */
>             re_set_syntax (RE_SYNTAX_POSIX_EGREP);
>             memset (&regex, 0, sizeof regex);
>             s = re_compile_pattern ("0|()0|\\1|0", 10, &regex);
>             if (!s || strcmp (s, "Invalid back reference"))
>               result |= 64;
> 

Looks good to me (modulo the line breaks that are probably caused
by your MUA).

Yes, we have to reuse some of the bits, because a program's return
code (> 0, < 126) has only room for 7 bits.

This test should also be added to tests/test-regex.c, so that we
verify that the choices made by regex.m4 have really achieved their
objective.

Bruno