Re: Async Python src block behavior with :dir header property

[Jack Kamm <jackkamm@gmail.com>]

Ihor Radchenko <yantar92@posteo.net> writes:

> Thanks!
> Attaching the two patches combined with some fixed to my patch.
>
> Please check if these two patches solve the discussed bug.

The original bug for async sessions looks fixed. But I encountered a
complication regarding the non-async bug of changing :dir. In particular
the following example:

#+begin_src python :dir otherdir :session pysession :return figname :results file value :mkdirp yes
  import matplotlib.pyplot as plt
  plt.figure(figsize=(1, 1))
  plt.plot([1, 2])
  figname = 'fig.svg'
  plt.savefig(figname)
#+end_src

#+RESULTS:
[[file:otherdir/fig.svg]]

#+begin_src python :dir otherdir2 :session pysession :return figname :results file value :mkdirp yes
  import matplotlib.pyplot as plt
  plt.figure(figsize=(1, 1))
  plt.plot([1, 2])
  figname = 'fig5.svg'
  plt.savefig(figname)
#+end_src

#+RESULTS:
[[file:otherdir2/fig5.svg]]

As you can see the second result points to the wrong directory. 

However, if replacing ":session pysession" with ":session *pysession*",
then it works.

It's because ob-python starts the session in buffer "*pysession*" (it
adds earmuffs around the session name when missing). So the following
doesn't find the inferior Python:

> +                   ((when-let ((session (cdr (assq :session params))))
> +                      (when (org-babel-comint-buffer-livep session)

Honestly, I'm not sure why ob-python insists on the session buffer
having the earmuffs, that behavior is from before my time. In
particular, I'm not yet sure if the motivation is just cosmetic (because
of the general convention like *shell*, *Python*, *R*, etc), or whether
it actually affects python.el behavior. But if it's just cosmetic, then
we might consider removing this behavior to simplify things.

Though note that ob-python is not the only one with this sort of
behavior -- looks like ob-lua might behave similarly, and until recently
ob-R also had some surprising behavior depending on whether the session
name had earmuffs.