[Fedora-packaging] perl module MODULE_COMPAT

[Warren Togami]

Michael Schwendt wrote:
> On Sat, 2 Apr 2005 05:26:40 +0200 (CEST), Dag Wieers wrote:
> 
> 
>>>>One important point, you are (or have been) effectively dropping support 
>>>>for every distro prior to FC1.
>>>
>>>No. That's what the perl-forward-compat package has been for:
>>>
>>>http://download.fedora.us/fedora/redhat/8.0/i386/RPMS.stable/perl-forward-compat-5.8.0-0.fdr.2.i386.rpm
>>
>>Seems reasonable, only that it is yet again different than how it is 
>>handled with python. I know the situation is a bit different, but the 
>>implementation is completely different. (naming and how versioning works)
> 
> 
> Yes, it's different, but it was subject to public discussion [1], and
> none of the few people who had comments disagreed strongly.
> 
> With the new and automated 'python(abi) = ...' dependency in FC4 devel,
> the solution on the Python side has become even more different, btw.
> 

MODULE_COMPAT was designed to allow for distinctions of more than just 
the version (which is all python-abi does).  This is necessary for perl 
and not python because it is possible to rebuild perl in different ways 
that breaks ABI compat, while python is almost entirely noarch.  This 
happened with the perl package IIRC in the RH8-RH9-RHEL3 timeframe.

Since then however perl has not broken ABI (?), so it seems that we have 
this seemingly overcomplicated construct.  But if we do break ABI again 
like in FC5 because we recompile the same version of FC4 perl with some 
new flag, MODULE_COMPAT can enforce exact deps and prevent incompatible 
FC4 packages from being installed on FC5.

Chip put a lot of thought into designing this.

Warren Togami
wtogami at redhat.com