Bugzilla Bug 168988

dev-perl/XML-SAX installs a file called ParserDetails where installed parsers
should be listed. One such other parser is XML-LibXML. Right now this file is a
normal installed file and thus overwrites the version already present with each
upgrade:

# emerge XML-LibXML
...
# grep . /usr/lib/perl5/vendor_perl/5.8.8/XML/SAX/ParserDetails.ini
[XML::SAX::PurePerl]
http://xml.org/sax/features/namespaces = 1
[XML::LibXML::SAX::Parser]
http://xml.org/sax/features/namespaces = 1
# emerge XML-SAX
...
# grep . /usr/lib/perl5/vendor_perl/5.8.8/XML/SAX/ParserDetails.ini
[XML::SAX::PurePerl]
http://xml.org/sax/features/namespaces = 1

I can see three solutions:
1. Handle ParserDetails.ini in postinst phase, like XML-LibXML does
2. Config-protect ParserDetails.ini
3. Have an eselect module take care of managing ParserDetails.ini

The first approach is more automatic, but if I understand things correctly the
default parser is derived from the order in this file, which it would break.

We might introduce a new configuration file where users can specify thir
precedence of parsers, and have every parser-related ebuild update the ini file
according to that file. This could be based on an eclass or an eselect module.

eselect module?! You are joking, right? o_O

Created an attachment (id=111790) [details]
Patch to XML-SAX-0.15.ebuild moving ParserDetails.ini setting to postinst

These modifications to the ebuild suppress the creation of ParserDetails.ini
during the install phase completely. Instead a corresponding call is makde in
postinst. The code there is taken from XML-LibXML but with an added "|| die".

This approach will make the default parser setting dependant on emerge order,
and as it is so far the ParserDetails.ini will still be around when you unmerge
XML-SAX. I'm not sure what the right solution would be there.

(In reply to comment #1)
> eselect module?! You are joking, right? o_O

I wasn't. Is eselect being deprecated, or is it simply not the right tool?

applied, thanks!