[Python-Dev] Binary CPython distribution for Linux

[Gregory Szorc]

I'm an advocate of getting users and projects to move to modern Python 
versions. I believe dropping support for end-of-lifed Python versions is 
important for the health of the Python community. If you've done any 
amount of Python 3 porting work, you know things get much harder the 
more 2.x legacy versions you need to support.

I led the successful charge to drop support for Python 2.6 and below 
from Firefox's build system. I failed to win the argument that Mercurial 
should drop 2.4 and 2.5 [1]. A few years ago, I started a similar 
conversation with the LLVM project [2]. I wrote a blog post on the 
subject [3] that even got Slashdotted [4] (although I don't think that's 
the honor it was a decade ago).

While much of the opposition to dropping Python <2.7 stems from the RHEL 
community (they still have 2.4 in extended support and 2.7 wasn't in a 
release until a few weeks ago), a common objection from the users is "I 
can't install a different Python" or "it's too difficult to install a 
different Python." The former is a legit complaint - if you are on 
shared hosting and don't have root, as easy as it is to add an alternate 
package repository that provides 2.7 (or newer), you don't have the 
permissions so you can't do it.

This leaves users with attempting a userland install of Python. 
Personally, I think installing Python in userland is relatively simple. 
Tools like pyenv make this turnkey. Worst case you fall back to 
configure + make. But I'm an experienced developer and have a compiler 
toolchain and library dependencies on my machine. What about less 
experienced users or people that don't have the necessary build 
dependencies? And, even if they do manage to find or build a Python 
distribution, we all know that there's enough finicky behavior with 
things like site-packages default paths to cause many headaches, even 
for experienced Python hackers.

I'd like to propose a solution to this problem: a pre-built distribution 
of CPython for Linux available via www.python.org in the list of 
downloads for a particular release [5]. This distribution could be 
downloaded and unarchived into the user's home directory and users could 
start running it immediately by setting an environment variable or two, 
creating a symlink, or even running a basic installer script. This would 
hopefully remove the hurdles of obtaining a (sane) Python distribution 
on Linux. This would allow projects to more easily drop end-of-life 
Python versions and would speed adoption of modern Python, including 
Python 3 (because porting is much easier if you only have to target 2.7).

I understand there may be technical challenges with doing this for some 
distributions and with producing a universal binary distribution. I 
would settle for a binary distribution that was targeted towards RHEL 
users and variant distros, as that is the user population that I 
perceive to be the most conservative and responsible for holding modern 
Python adoption back.

[1] 
http://permalink.gmane.org/gmane.comp.version-control.mercurial.devel/68902
[2] http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-December/056545.html
[3] 
http://gregoryszorc.com/blog/2014/01/08/why-do-projects-support-old-python-releases/
[4] 
http://developers.slashdot.org/story/14/01/09/1940232/why-do-projects-continue-to-support-old-python-releases
[5] https://www.python.org/download/releases/2.7.7/