Ihor Radchenko <yantar92@posteo.net> writes:

> Rudolf Adamkovič <salutis@me.com> writes:
>
>> :
>> : > > hello
>>
>> on the subsequent runs.
>>
>> Better than the new version but still wrong. :)
>
> And this is what drove me crazy during debugging. I do not understand
> the logic of all that ob-comint code.
>
> I have identified that the hang happens because Org does not change PS2
> prompt. Just PS1. But fixing this would yield to
>
> : org_babel_sh_prompt> org_babel_sh_prompt> hello
>
> Then, I tried to see how the original code works. And it does not
> :facepalm:
>
> I asked emacs-devel
> https://yhetil.org/emacs-devel/87y1tgqhmc.fsf@localhost/T/#u

See the attached tentative patch.
I'd appreciate some testing. Hopefully, I did not break anything.
Comint is tricky.