How to install Python 3.3 (not 3.4) on OS X with Homebrew?

Question

If you install python3 through Homebrew it installs the latest version by default, which I did. But I want 3.3 instead of 3.4. How can I replace it with 3.3 specifically using Homebrew? I want to try Django with Python 3 but I'm just learning Django so I want to use the latest stable version, currently 1.6, which is compatible with up to Python 3.3. I want to use it with Python 3, so it has to be 3.3. Django 1.7 is Py3.4 compatible but I don't want to mess with that 'til it's stable... on OS X 10.8.5

Solution

Here are some elements that you can piece together from the homebrew FAQ.

1. Can I edit formulae myself? - yes.

   brew edit python3
   

2. look for the url and change it to the ftp link to the 3.3 (3.3.6) archive.

3. download the archive locally and compute the checksum with shasum.

4. save the file as python33.rb and install with brew install --debug python33.rb.

Passing the --debug flag will help you in case some steps are not working properly (e.g. in the latest formula, removing the 2to3 binary was a problem), you may just try to revert this change as python3.3 does not have ensurepip bootstrap module.

You can find the formula I used here: python 3.3.5