Date: Thu, 14 Oct 2021 16:38:02 -0700
From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>,
	Josef =?utf-8?B?xaBpbcOhbmVr?= <josef.simanek@gmail.com>,
	Dagfinn Ilmari =?utf-8?Q?Manns=C3=A5ker?= <ilmari@ilmari.org>,
	Pg Hackers <pgsql-hackers@postgresql.org>
Subject: Re: [RFC] building postgres with meson
Message-ID: <20211014233802.ungwz2qafz37eqna@alap3.anarazel.de>
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Hi,

On 2021-10-14 18:08:58 -0400, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > Hm, so it seems we should make the test separately verify that perl -M{Opcode,
> > ExtUtils::Embed, ExtUtils::ParseXS} doesn't fail, so that we can fail perl
> > detection with a useful message?
>
> Our existing policy is that we should check this at configure time,
> not later.

Yea, I was thinking of configure (and meson's equivalent) as well.


> Since plperl won't work at all without Opcode, it seems
> appropriate to add a check there if you say --with-perl.  I wasn't
> aware that Red Hat had unbundled that from the minimal perl
> installation :-(.
>
> OTOH, if they've not unbundled ExtUtils::Embed or ExtUtils::ParseXS,
> I doubt it's worth the configure cycles to check for those separately.

On debian the perl binary, with a sparse set of modules is in
perl-base. ExtUtils::Embed and ExtUtils::ParseXS are in
perl-modules-x.yy. Whereas Opcode is in libperlx.yy. But libperlx.yy depends
on perl-modules-x.yy so I guess an Opcode.pm check would suffice.

Seems we can just check all of them at once with with something like

perl -MOpcode -MExtUtils::Embed -MExtUtils::ParseXSNotAvailable -e ''
Can't locate ExtUtils/ParseXSNotAvailable.pm in @INC (you may need to install the ExtUtils::ParseXS3 module) (@INC contains: /home/andres/bin/perl5/lib/perl5/x86_64-linux-gnu-thread-multi /home/andres/bin/perl5/lib/perl5 /etc/perl /usr/local/lib/x86_64-linux-gnu/perl/5.32.1 /usr/local/share/perl/5.32.1 /usr/lib/x86_64-linux-gnu/perl5/5.32 /usr/share/perl5 /usr/lib/x86_64-linux-gnu/perl-base /usr/lib/x86_64-linux-gnu/perl/5.32 /usr/share/perl/5.32 /usr/local/lib/site_perl).

Greetings,

Andres Freund