Does everyone really agree that it's "wise to use no hard tabs in code"? There are quite a few comments at the bottom of that page favouring tabs. See also Why tabs are clearly superior and Why I love having tabs in source code.

I use tabs. I'd compare tabs versus spaces to semantic HTML versus presentational HTML. By using tabs, you can view my source in a text editor with tab stops set to two spaces, four spaces, eight spaces or whatever, and it still looks sensible - I don't enforce my favourite indentation level on you.

Anyway, enough of that, that's not the main point of your post...

Project metadata: what I've been doing lately is to have a directory called meta inside the root directory of the project. This contains zero or more RDF files with project metadata - changelogs, credits, links to the bug tracker, repository, etc.

This can be all in one file, or split up arbitrarily - they are all combined into one in-memory model when they're processed. Currently I tend to use one file for a changelog, one for general project metadata, and a third one for keeping track of dependencies.

My Makefile.PL then assembles this into META.yml and Changes files, figures out the project's licence and creates a LICENSE file too. It does all that at the author side when making a distribution - thus the libraries for metadata management don't need to be installed at the end user's side.

The code for doing all this is on CPAN (of course):

• Module::Install::DOAP - generate META.yml and LICENSE from metadata
• Module::Install::DOAPChangeSets - generate Changes from metadata
• Module::Install::RDF - common bits of above two, factored out into a separate module
• Test::RDF::DOAP::Version - tests that metadata changelog is up to date

Here's an example of a project that uses it: repo and distributed code on CPAN. Notice the size of Makefile.PL? 42 bytes. No metadata there - it's all in the meta directory.

update: here's another (bigger) project using the same metadata system.