Re: [PATCH v3] meson: disable PCRE2 dependency by default in macOS

From: Eli Schwartz <eschwartz@gentoo.org>
Date: Jul 15, 2025, 14:14 UTC
Message-ID: <2f068703-1825-464c-94da-d20f96ed9591@gentoo.org>
In-Reply-To: <CAPUEsphA-XadsPU1mkdTQM7qjMKtZP8gJXWwZ8WmFutj8WS_rg@mail.gmail.com>

On 7/15/25 8:08 AM, Carlo Arenas wrote:

> On Tue, Jul 15, 2025 at 3:32 AM Patrick Steinhardt <ps@pks.im> wrote:
>>
>> On Tue, Jul 15, 2025 at 01:56:44AM -0700, Carlo Arenas wrote:
>>> On Tue, Jul 15, 2025 at 1:46 AM Patrick Steinhardt <ps@pks.im> wrote:

Show 11 quoted lines

>>>> Agreed. I guess tha only reason why I picked "enabled" here is because
>>>> we also got a wrapper in "subprojects/". But with this new workaround in
>>>> place I agree that it is sensible to switch to "auto".
>>>
>>> AFAIK the "wrapper" fallback still kicks in when the feature is "auto"
>>
>> It does, yes. But with 'auto' as default it means that we're free to
>> disable PCRE2 if we have detected a broken PCRE2 dependency.
> 
> My bad, I was mistaken and indeed auto doesn't fallback to the wrap, so
> this will likely regress in windows if it is not invoked with `-Dpcre2=enabled`

See https://mesonbuild.com/Reference-manual_functions.html#dependency_allow_fallback

The default is to fallback to the wrap for *required* dependencies (rather than abort the build). If it's desirable to have "auto" attempt to automatically enable the feature if

system_found || \
(!wrap_mode_nofallback && (have_internet_for_wrap || \
    have_locally_downloaded_wrap ))

then you can use that "allow_fallback" kwarg.

-- 
Eli Schwartz