Bug#619275: Perl Policy change to document major version upgrade trigger

[Niko Tyni <ntyni@debian.org>]

On Tue, Mar 22, 2011 at 04:35:16PM +0000, Dominic Hargreaves wrote:
> +
> +      <sect id="perl_upgrades">
> +        <heading>Perl Package Upgrades</heading>
> +        <p>
> +          Starting from <package>perl</package> 5.12.3-2, a dpkg trigger
> +          named <var>perl-major-upgrade</var> will be triggered by the
> +          postinst of the <package>perl</package> package during major
> +          upgrades. Some examples of things which consitute a major upgrade
> +          are an upgrade which would change the value of versioned
> +          directories in <tt>@INC</tt>, or one which changes <tt>abiname</tt>.
> +          Any package may declare an interest in the trigger, especially
> +          packages including long-running daemons which would stop working
> +          until restart.
> +        </p>
> +        <p>
> +          It is suggested that such packages include an appropriate section
> +          in their postinst to handle the trigger by restarting relevant
> +          daemons or notifying users of further action.
> +        </p>
> +      </sect>

While I do think this is a nice solution, I've got a couple of concerns:

- is this overkill? Would it be enough for the long running daemons to just
  register an interest in a file trigger on /usr/bin/perl ? This means
  minor perl upgrades will activate the trigger too, but that may well
  be a good thing - think of security fixes and the like. (OTOH, this
  approach doesn't help daemons embedding libperl...)

- is it too early to put this in policy? Generally policy documents existing
  practice, but no package is using this yet. Should we wait for at least some
  level of adoption, probably by filing wishlist bugs on known affected daemons
  like spamassassin, and see how it works out first?

-- 
Niko Tyni   ntyni@debian.org