On Fri, Jul 19, 2013 at 5:29 AM, Paul Moore <p.f.mo...@gmail.com> wrote: > On 19 July 2013 05:23, Nick Coghlan <ncogh...@gmail.com> wrote: >> >> On 19 July 2013 09:37, Vinay Sajip <vinay_sa...@yahoo.co.uk> wrote: >> >> I think the point is that people might be dependent on this >> >> functionality and >> > >> >> changing it out from underneath them could break their world. >> > >> > >> > I got the point that Daniel made, and my question was about *how* their >> > world would break, and whether we really need to support multiple versions >> > of something installed side-by-side, with on-the-fly sys.path manipulation. >> > If that is a real requirement which should be supported, shouldn't there be >> > a PEP for it, if it's coming into Python? It's not supported by distutils, >> > and it has been a point of contention. >> >> It's a real requirement - Linux distros need it to work around >> parallel installation of backwards incompatible libraries in the >> system Python. Yes, it's an implementation defined feature of >> pkg_resources (not setuptools per se), but it's one that works well >> enough even if the error message can be opaque and the configuration >> can get a little arcane :) > > > Just to be absolutely clear on my interest in this: > > 1. I believe (but cannot prove, so I'll accept others stating that I'm > wrong) that many people using setuptools for the console-script entry point > functionality, have no specific interest in or requirement for > multi-version. As an example, take pip itself. So while it is true that > functionality will be lost, I do not believe that users will actually be > affected in the majority of cases. That's not to say that just removing the > functionality without asking is valid. > > 2. Projects typically do not declare a runtime dependency on setuptools just > because they use script wrappers. Maybe they should, but they don't. Again, > pip is an example. So wheel-based installs of such projects can break on > systems without setuptools (pkg_resources). This is going to be a bigger > problem in future, as pip install from wheels does not need setuptools to be > installed on the target (and if we vendor setuptools in pip, nor does > install from sdist). Of course, after the first time you hit this, you > install setuptools and it's never a problem again. But it's a bad user > experience. > > 3. It's an issue for pip itself, as we explicitly do not want a dependency > on a system installed setuptools. So we have to hack or replace the > setuptools-generated wrappers. > > Paul.
pip should just add pkg_resources as a dependency for any package that has console_scripts entry points. _______________________________________________ Distutils-SIG maillist - Distutils-SIG@python.org http://mail.python.org/mailman/listinfo/distutils-sig
