From: PJ Eby <pje@telecommunity.com>
FWIW, the original reason I argued for relative paths in PEP 376 is supporting installations that are shared across architectures for cross-platform development. At OSAF, it was common to have a single installation directory shared by a Linux, Mac, *and* Windows machine simultaneously. Absolute paths would break in such a scenario, as each accessing machine would see a different absolute path. Some of setuptools' design is specifically mangled to handle this kind of thing.
Is this a mainstream use case, though? I'm not dead set against relative paths, but looking for simplicity if possible. Nowadays the thinking seems to be around using isolated environments even on a single platform, rather than trying to share across projects. After all, disk space is cheap. The other thing is that using *only* relative paths doesn't cut it - there are circumstances where you write files outside site-packages, so you would need absolute paths for those files (or incredibly convoluted relative ones), and that wouldn't work well in the OSAF scenario you described, anyway. Regards, Vinay Sajip