Re: What am I doing wrong? A bad end-user experience

On Thu, Sep 10, 2026 at 7:50 AM Paul "LeoNerd" Evans <[email protected]>
wrote:

> I keep a bunch of perl modules in my $HOME:
>
>   $ env | grep PERL
>   PERL5LIB=/home/leo/lib/perl5
>   PERL_MB_OPT=--install_base=/home/leo
>   PERL_MM_OPT=INSTALL_BASE=/home/leo
>
> I use system perl.
>
> Today, I ran some debian updates that jumped from perl 5.40 to 5.42.
> Now, nothing is usable:

...
> This exact problem of "argh all my perl is broken" is going to happen
> to anyone doing this kind of setup, whenever system perl gets updated.
>
> So someone, please tell me, what am I doing wrong here? I cannot
> believe that this is the intended behaviour of the system we have.
>
> Alternatively, maybe this is as good as can currently be achieved. If
> so then I really don't like it, and I think we could do a lot better.
>
> <rant>
>   If users can't easily install newer versions of perl and have things
>   actually still usable, then I can quite well understand why people
>   don't update to newer versions, and so keep using ancient versions and
>   not bother making use of new features so nobody uses anything new that
>   we make and so why do we spend time making anything new?
> </rant>
>

My personal tactic is to avoid polluting system perl, which is managed by a
package manager, with CPAN installations that are not managed by that
package manager. The package manager enables it to sensibly upgrade in
place, but the same is not true for any sitelib-installed modules or
local::lib installed modules. The former is protected by versioned dirs;
local::lib is not. The true "solution", aside from not doing this and
somehow discouraging people from doing it, is to make local::lib install to
a versioned dir which `use lib` already recognizes, but the result of this
just like with sitelib is that after the upgrade no CPAN modules will be
usable, which still isn't a great user experience but better than
"everything is broken, and you have to ask someone how to repair it".

-Dan