On Thu, 2 Mar 2017 16:09:21 -0300 Mauro Carvalho Chehab mchehab@s-opensource.com wrote:
IMHO, the way Python and python libraries break compatibility is crazy.
Good packaging sense says that, if APIs can break on every single new release (with seems to be the case of docutils), then a package depending on such bad-developed library should require the exact version(s) it is known to work.
When we're discussing about the docs toolchain, I mentioned that I was afraid that the Python development model would cause this sort of issues. Unfortunately, it seems that my concerns were pertinent :-(
It doesn't have to be that way... The LWN site is a Python application that has been running since 2002 without any significant issues of this type, despite having some significant external dependencies. There is nothing inherent in Python that creates this kind of mess, it's really just a matter of having the same discipline that you need when writing a library in any other language.
It would appear that this discipline is severely lacking in the docutils camp in particular.
One way kids these days handle such issues is to just bundle up all the dependencies they are about and ship their own copies. This isn't just Python; see https://lwn.net/Articles/712318/ for some much worse examples. But I don't think we want to do that.
There does not appear to be an ideal solution here. I wonder if we want do to something like this:
- Put in a little test program to verify that the build system has versions of sphinx and docutils that play well together.
- Add a script to create a working combination in a virtualenv for people who need it. If the build process sees one of those in place, it should use it.
I feel pretty strongly that the build should *not* just go off and do the virtualenv thing automatically. We should not be fetching and installing external software on somebody's system, even in a contained environment, without an explicit request to do so.
Look for a grumpy article on your favorite news site in the relatively near future...:)
jon