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

[Jonathan Nieder <jrnieder@gmail.com>]

Dominic Hargreaves wrote:

> A not-so-recent bug report, #230308, raised the issue of how a long-running
> program which would be broken (until restart) by a major Perl package upgrade
> (eg from 5.10 to 5.12) could be notified of such a restart. There was a rough
> consensus on that bug report that, once triggers were available, they could
> be used as means to this end, as proposed on that bug report.

Thanks, Dominic.  Cc-ing debian-perl for seconds and other thoughts.

[...]
> As such, perl 5.12.3-2, currently in experimental, implements the perl
> half of this fix, by triggering the perl-major-upgrade trigger if it is
> upgraded from a version older than 5.12.0. I've tested this against a
> modification of the spamassassin package which implements the receiving
> side of the proposal, with success. The implementation is for all
> practical purposes identical to the proof of concept posted by Niko to
> the original bug.
>
> My proposed modification to the Perl policy is a new section entitled
> "Upgrades", attached as a patch against git.

Signed-off-by: Dominic Hargreaves <dom@earth.li>
---
 perl-policy.sgml |   20 ++++++++++++++++++++
 1 files changed, 20 insertions(+), 0 deletions(-)

diff --git a/perl-policy.sgml b/perl-policy.sgml
index b9f3277..47cf9f6 100644
--- a/perl-policy.sgml
+++ b/perl-policy.sgml
@@ -461,6 +461,26 @@ perl -MExtUtils::Embed -e ldopts
 	  package must depend upon it explicitly.
 	</p>
       </sect>
+
+      <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>
     </chapt>
 
     <appendix id="perl6">
-- 
1.7.0.4