From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Fri, 20 Mar 2026 07:55:54 GMT
Subject: Re: [PATCH] regex: not all macOS platforms seem to have REG_ENHANCED
Message-ID: <6636e7d2-7a1d-0108-2e62-af27a3ae3cf3@gmx.de>
In-Reply-To: <xmqq8qbnigxp.fsf@gitster.g>

Hi Junio,

On Fri, 20 Mar 2026, Junio C Hamano wrote:

> Earlier, 54463d32 (use enhanced basic regular expressions on macOS,
> 2023-01-08) started to use the REG_ENHANCED option when ERE is not
> in use on macOS.  The build seems to have started failing on
> macos-14 CI jobs at GitHub, however, as apparently not all the macOS
> platforms have this flag defined.
> 
> Signed-off-by: Junio C Hamano <gitster@pobox.com>
> ---
>  compat/regcomp_enhanced.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/compat/regcomp_enhanced.c b/compat/regcomp_enhanced.c
> index 84193ce53b..51e1358170 100644
> --- a/compat/regcomp_enhanced.c
> +++ b/compat/regcomp_enhanced.c
> @@ -3,7 +3,9 @@
>  
>  int git_regcomp(regex_t *preg, const char *pattern, int cflags)
>  {
> +#ifdef REG_ENHANCED
>  	if (!(cflags & REG_EXTENDED))
>  		cflags |= REG_ENHANCED;
> +#endif

While this lets the build pass, it _does_ change behavior. Where
previously, EREs were enforced, now BREs are silently enforced.

So it might be desirable to instead imitate what `meson.build` does,
namely define `USE_ENHANCED_BASIC_REGULAR_EXPRESSIONS` on macOS when
compiling with `clang`.

But that should already be the case:
https://gitlab.com/git-scm/git/-/blob/v2.53.0/config.mak.uname#L151

> ifeq ($(uname_S),Darwin)
> [...]
> 	USE_ENHANCED_BASIC_REGULAR_EXPRESSIONS = YesPlease

So: hmm.

Ciao,
Johannes

>  	return regcomp(preg, pattern, cflags);
>  }
> -- 
> 2.53.0-816-g44373249a2
> 
> 
>