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Postings from January 2005
David A. Golden wrote: > I asked a question about the latest thinking on version numbers in > modules on perlmonks and got a tremendously wide range of answers -- and > certainly no consensus that all modules need a VERSION. In fact, > several people went the opposite route, leaving just a single VERSION > for the master module so that the distribution version is built > correctly and leaving all other modules VERSION-less. > > http://perlmonks.org/index.pl?node_id=417576 I'm sorry that I don't have as much time to attend to perlmonks as I should. I'll try and spend some time reading and then commenting on that thread; for better or worse, I am the $VERSION expert, having spent nearly two years in the core detangling the web of inconsistencies. ;( However let me rephrase my original statement: All modules _in the core_ must have a $VERSION number, even if it is just a reference to some other module's $VERSION (this is not the best but it is better than naught). The reason for this is that once modules are in the core, they can get individually modified and their parent module might not change (or even be updated timely on CPAN for dual-life modules). Without a $VERSION in all modules in the core, the odds of changes being missed are high and for dual-lifed modules the odds of desynchronization between core and CPAN is very high. A couple of years ago, someone went through and added $VERSION's to all core modules; I suppose I should check to make sure that is still the case... At the same time, any module which is released to CPAN _should_ have a $VERSION, even if it is basically a private module of some other module. The reason flows out of the above paragraph - if the module would ever be considered for the core, it needs a $VERSION. A package scalar is cheap (in the larger picture of the overhead Perl requires). If you would ever want to spin off a given sub-module into it's own distribution, it will have to have a $VERSION, so you might as well give it one now, rather than waiting until later. That being said, if you are writing modules for your own use, and you don't intend to release it into the public, there is no reason for $VERSION at all. It is strictly there to facilitate good inter-module dependencies. > > CPAN seems not to care if there's a version -- pulling from the suffix > on the distribution tarfile, right (or maybe using a META file)? Actually from the Makefile.PL; if that refers to a module name, then that file is parsed to get the $VERSION, else that number is used as the CPAN version. > The suggestion that M::B::Base simply define version seems like an easy > solution. It doesn't even need to be $VERSION=$Module::Build::VERSION > -- it could be anything so long as it's early enough in the file that > other tools find it and stop searching. I agree that this would fix this immediate problem, but not the deeper issue that M::B::Base is trying to ignore version.pm magic, which isn't possible in bleadperl (since that is all there is there). John -- John Peacock Director of Information Research and Technology Rowman & Littlefield Publishing Group 4501 Forbes Boulevard Suite H Lanham, MD 20706 301-459-3366 x.5010 fax 301-429-5748Thread Previous