On 02/09/2010 08:10 AM, Ralf Corsepius wrote: > On 02/08/2010 06:10 PM, Gabor Szabo wrote: >> Hi, >> >> I saw these bug reports starting to flow in two days ago, >> just in time to mention them during my talk on FOSDEM. >> >> The problem seems to be that the rpm builder extracted the list of >> dependencies of Padre from its source code. This did not notice that >> Win32::API is use only when running on Windows and thus it was >> included in the list of dependencies. >> >> The right way would be to use the list of dependencies as supplied in >> the META.yml file in the Padre tarbal. >> >> Dave Cross blogged about this probably explaining in a much better way >> than I did: >> http://perlhacks.com/2010/02/building-rpms-from-cpan-distributions.php > > Though I partially agree with Dave on his "rpm does something > brain-dead" statement, I think his reasoning suffers from a thinko: > > <cite> > And that's, of course, where the RPM builders should be going to get a > list of dependencies. META.yml contains the list of other modules that > the author wants the module to depend on. This should be seen as the > definitive list. Of course, there might be errors in that list - but > that should be addressed by raising a bug against the module. > </cite> > > IMO, he misses that what a perl-module's author thinks he wants "his > module to depend on" is largely irrelevant to Fedora. > What is relevant to Fedora, is "what the module actually uses" and what > we _want_ it to actually use. > > > These sets overlap, but ... they are not identical. > > Example: Putting bugs in Meta.yml aside (they are not so uncommon as > people might believe), a classical corner-case in rpm-packaging > perl-modules are "Perl required'ed modules" (i.e. optional modules). If a module is optional, then it's not required and shouldn't be listed as a dependency. Do you have an example that illustrates your point? Going back to the Plack example I used in my blog post. There are a huge number of modules that Plack can make use of it they are installed on your system. But if they aren't, Plack will still work fine - but it may be that some functions won't be available. If, however, you subsequently install the missing modules, this functions become available to you. In my opinion, these modules are not essential and shouldn't be listed as dependencies. I suspect this is where our philosophical differences will lie. > To us, they often are not optional, but mandatory (rpm's "Requires:"), > because rpm doesn't have a concept of "optional requires". META.yaml has Requires and BuildRequires lines. These map directly onto the same concepts in RPM. META.yml also has a (little-used) Recommends lines. I don't think RPM has a concept like that. I can think of two corner cases where META.yml doesn't (yet) do the right thing. 1/ There are cases where certain modules are required in certain circumstances. For example, Padre needs Win32::API if it's running on Windows. META.yml doesn't have a way to model those kinds of "optional dependencies". 2/ Some modules require any one from a set of dependencies. For example JSON::Any requires one from the list JSON::XS, JSON and JSON::DWIW. Clearly, each system only needs one of those installed, but you can't list any of them as a dependency. And even if you could, would RPM support this model? So yes, there are still a few issues with META.yml. But, in general, I think it gives a better starting point than the current behaviour of looking for all of the "use" (and "require") statements. > Finally: I question your claim of "META.yml" to be always right. I know that META.yml isn't always going to be right. But when it isn't, that should be treated as a bug in the upstream distribution and reported back to the author - perhaps including a patch. (Yes, this opens a whole new can of worms about unresponsive or missing CPAN authors. This is something that the Perl community is aware of and is planning to address.) Cheers, Dave... -- Fedora Extras Perl SIG http://www.fedoraproject.org/wiki/Extras/SIGs/Perl perl-devel mailing list perl-devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/perl-devel
