Re: [PATCH 2/2] lib: fix glibc-2.43 w/ clang

Subject: Re: [PATCH 2/2] lib: fix glibc-2.43 w/ clang

Date: Mon, 16 Feb 2026 12:12:08 +0100

To: Martin Jambor

Cc: Nicolas PARLANT, notmuch@notmuchmail.org

From: Michael J Gruber

Am Mo., 16. Feb. 2026 um 11:52 Uhr schrieb Martin Jambor <mjambor@suse.cz>:
>
> Hello,
>
> On Mon, Feb 16 2026, Michael J Gruber wrote:
> > Am So., 15. Feb. 2026 um 23:13 Uhr schrieb David Bremner <david@tethera.net>:
> >>
> >> Nicolas PARLANT <nicolas.parlant@parhuet.fr> writes:
> >>
> >> >>notmuch-insert.c:136:11: error: assigning to 'char *' from 'const char *'
> >> >>      discards qualifiers
> >> >>      [-Werror,-Wincompatible-pointer-types-discards-qualifiers]
> >> >>  136 |     slash = strrchr (path, '/');
> >> >>      |           ^ ~~~~~~~~~~~~~~~~~~~
> >>
> >> Thanks for the patch. The change itself looks fine, but the (subject of)
> >> the commit message is a bit cryptic. We use "lib:" for code in the lib/
> >> or (maybe util/) directory. This is obvious not a fix for glibc, but
> >> that's what a naive reader (like me) might think.
> >
> > That makes two of us :)
> >
> > Also: How is the patch related to glibc version? Has the declaration
> > of strrchr() changed?
>
> See https://sourceware.org/pipermail/libc-alpha/2026-January/174374.html
> specifically:
>
>   * For ISO C23, the functions bsearch, memchr, strchr, strpbrk, strrchr,
>     strstr, wcschr, wcspbrk, wcsrchr, wcsstr and wmemchr that return
>     pointers into their input arrays now have definitions as macros that
>     return a pointer to a const-qualified type when the input argument is
>     a pointer to a const-qualified type.
>
> (and similar items in the list)

Thanks for the link.

The main point is still about being clear in the commit message: "Fix"
indicates something is broken. What is broken? Is this a warning with
clang, an error leading to build failure in default settings or with
-Werror?

Even after reading the above it's not clear what strrchr was before
and  - more importantly - whether the "fixed" code still compiles with
strrchr() from older glibc. In an ideal world, commit messages are
longer than the patch body ;-)

Cheers,
Michael
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