Subject: Re: [PATCH v2 2/2] meson: fix Perl version check for Meson versions before 1.7.0

From: Patrick Steinhardt <[email-masked]>
Date: Mon, 27 Jan 2025 08:39:39 +0100

On Fri, Jan 24, 2025 at 04:30:49PM +0000, Peter Oliver wrote:
> diff --git a/meson.build b/meson.build
> index f01d81b39f..80af578d36 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -755,7 +755,11 @@ endif
>  
>  # Note that we only set NO_PERL if the Perl features were disabled by the user.
>  # It may not be set when we have found Perl, but only use it to run tests.
> -perl = find_program('perl', version: '>=5.26.0', dirs: program_path, required: perl_required)
> +if meson.version().version_compare('>=1.5.0')
> +  perl = find_program('perl', dirs: program_path, required: perl_required, version: '>=5.26.0', version_argument: '-V:version')
> +else
> +  perl = find_program('perl', dirs: program_path, required: perl_required, version: '>=26')

I'm still a bit sceptical whether we should adapt this second line to
match against `>=26`. I guess as long as it doesn't break anything out
there it's okayish, and if we do see breakage we can in the worst case
revert it.

In any case, it deserves a comment why we're matching against the minor
version and not the whole version. E.g. something like this:

    # Executing `perl --version` results in a string similar to the
    # following output:
    #
    #     This is perl 5, version 40, subversion 0 (v5.40.0) built for x86_64-linux-thread-multi
    #
    # Meson picks up the "40" as version number instead of using "v5.40.0"
    # due to the regular expression it uses. This got fixed in Meson 1.7.0,
    # but meanwhile we have to either use `-V:version` instead of `--version`,
    # which we can do starting with Meson 1.5.0 and newer, or we have to
    # match against the minor version.

Thanks!

Patrick