Re: [PATCH] get_maintainer: lazy load JSON::PP only when --json is used

[Oleg Nesterov <oleg@redhat.com>]

On 10/30, Joe Perches wrote:
>
> On Fri, 2026-10-30 at 22:44 +0100, Oleg Nesterov wrote:
> >
> > > Dunno.  Depending on the current failure output
> > > maybe adding something like the below is better:
> > >
> > > use Module::Load::Conditional qw(check_install);
> > >
> > > if (!check_install(module => 'JSON:PP')) {
> > >     die "$P: --json not available - missing perl module JSON:PP\n";
> > > }
> >
> > But why? Why make get_maintainer.pl depend on yet another module?
> > FYI, on my Fedora 44
> >
> > 	$ perl -we 'use Module::Load::Conditional qw(check_install);'
> > 	Can't locate Module/Load/Conditional.pm in @INC (you may need to install the Module::Load::Conditional module) (@INC entries checked: /usr/local/lib64/perl5/5.42 /usr/local/share/perl5/5.42 /usr/lib64/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib64/perl5 /usr/share/perl5) at -e line 1.
> > 	BEGIN failed--compilation aborted at -e line 1.
>
> Module::Load is a core perl module since 5.10 and
>
> I think you are using a broken version of a perl installation

And how do you think it is broken? my laptop runs the fresh Fedora 44.

I used ./scripts/get_maintainer.pl many years, almost every day, and I never
needed to install the additional modules. Until ("get_maintainer: add --json
output mode")

> and I think you should:
>
> $ sudo dnf install perl-core

Oh. I LOVE perl. Damn I still consider myself as a perl programmer ;)

But why do you think I should install the additional modules (which I will
never use) on my machine???

Again, again, again. AFAICS, this patch makes no difference if JSON::PP
is installed. Please correct me.

It just allows to use get_maintainer.pl without --json in the case when
JSON::PP is NOT installed. This is the ONLY difference afaics.

> > And for what ???
>
> My idea is to make it more obvious _why_ something fails
> and not like get_maintainer itself is broken.

Good idea! But again, again, again, if JSON::PP is not installed, then the
failure message is the same with or without my patch. Just get_maintainer.pl
does NOT fail without --json.

Although to be honest "Can't locate JSON/PP.pm ..." looks very clear to me,
but you can make it more obvious with or without my patch.

> > If we want to "improve" the errmsg, we can use "eval { require JSON::PP; }; die ... if $@"
> > but this looks absolutely pointless to me.
>
> We disagree.  I prefer output errors to look less broken.

less broken than what? see above.

It's not that we disagree... Worse, we can't understand each other :(
Perhaps is this my fault.

Oleg.