GNU bug report logs - #77476
[PATCH] Rename various hash functions to avoid clashing with GnuTLS.

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Message #29 received at 77476-done <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Eli Zaretskii <eliz <at> gnu.org>
Cc: 77476-done <at> debbugs.gnu.org, woods <at> robohack.ca
Subject: Re: bug#77476: [PATCH] Rename various hash functions to avoid
 clashing with GnuTLS.
Date: Sat, 19 Apr 2025 22:32:44 -0700

[Message part 1 (text/plain, inline)]

On 2025-04-19 06:50, Eli Zaretskii wrote:
> Paul, could you please chime in, since these are Gnulib
> functions we're talking about.

GnuTLS incorrectly exports some Gnulib functions to the outside world, 
and this breaks programs that use these function names for their own 
purposes.

Gnulib has a way to fix this: its lib-symbol-visibility module. GnuTLS 
should use this (or do the equivalent by hand), but doesn't. I suppose 
GnuTLS has other visibility problems like this, and they should all be 
fixed. I filed a bug report with the GnuTLS folks about this; see 
<https://gitlab.com/gnutls/gnutls/-/issues/1703>.

Possibly this problem even affects normal (i.e., dynamically linked) 
Emacs on some platforms. As Greg says, the semantics of name clashes is 
not portable, and I am particularly worried about what would happen if 
dynamically loaded modules refer to the clashing names on some random 
platform. As we can't expect GnuTLS to fix their bug soon, or for all 
our users to update to the fixed GnuTLS version soon, we should change 
the Emacs names to avoid the clash in the meantime.

It's just two names so I did that, by installing the attached patch on 
master. I changed "hash_string" to "hash_char_array" which is a more 
accurate name as the argument is not a C string, and I changed 
"hash_lookup" to "hash_find" which is a bit shorter. I also changed two 
other names to match.

I doubt whether this patch is urgent enough to backport to the emacs-30 
branch. Hardly anybody links statically; the GnuTLS build procedure even 
warns against doing static linking (due to other static-linking problems 
that Emacs does not run into). And most likely, dynamically-linked 
modules won't use the clashing symbols.

Marking the bug as done.

[0001-Avoid-name-clashes-with-static-GnuTLS.patch (text/x-patch, attachment)]

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