Ihor Radchenko <yantar92@posteo.net> writes:

> Peter Mao <peter.mao@gmail.com> writes:
>
>> Expectation:  When running ob-python code blocks, I should be able to
>> kill the python session in the *Python* buffer and run another code
>> block (or the same one).
>>
>> Problem:  ob-python works fine on the first execution, but after
>> `exit()`ing the python session, it hangs without executing the code.
>> After a `C-g`, the prompt in the *Python* session shows up, but one then
>> has to re-execute the code block, as none of it has run.
>
> Confirmed.
>
> It looks like `python-shell-first-prompt-hook' does not get triggered
> in the described scenario with exit() and we enter infinite loop in the
> code below.

I think `python-shell-first-prompt-hook' is actually still triggered,
but rather it is `org-babel-comint-wait-for-output' that is hanging
while waiting for startup. However, we can just replace it with a
`sleep-for' instead, because we now wait for
`org-babel-python--initialized' anyways.

See the attached patch. Please let me know if it fixes the problem for
you.