bug#17370: 24.3.90; user cannot disable inferior python run from python-mode when file is visited

[Glenn Morris]

Glenn Morris wrote:

> (python-shell-internal-send-string "import sys;print ('\\n'.join(sys.path))")
>
> It is this that hangs (in python-shell-send-string-no-output AFAICS).
> It also hangs in Emacs 24.3.
>
> emacs -Q -l python

It seems that for me the hang is because I have customized my python
prompt (sys.ps1 = 'py> ' in ~/.pythonrc.py).

I have to set python-shell-prompt-regexp to match to avoid a hang as
python.el thinks it needs to keep waiting for process output.

Can python.el be made more robust in this regard?

Otherwise there needs to be a big fat warning attached to
python-shell-prompt-regexp.