Re: Python and propagation

[Andreas Enge]

On Thu, Feb 18, 2016 at 01:21:48PM +0100, Ricardo Wurmus wrote:
> 2) avoid PYTHONPATH, patch all Python files invasively!
>     import sys
>     sys.path.append("/gnu/store/cabba9e...-numpy.../lib/...")

That sounds great! It appears to me as if you have found the equivalent of
a RUNPATH for python scripts.

It could more or less be done like the patch-shebangs phase. To me it
does not look difficult to implement. Assume it is done in a separate
phase after patching shebangs:

- Create a list of all the python inputs of the package; these are the
  inputs the package name of which starts with "python-". Or the directory
  names "/gnu/store/xxx-python-xxx", depending on what is available in
  the phase.
- Construct the corresponding string to add to the python scripts.
- Look for files starting with a shebang and having "python" as part
  of the interpreter. Then add the string after the first, shebang line
  in all these files.

Or is it more complicated than that?

Andreas