Re: Multiple prompts when starting inferior Python

["Andreas Röhler" <andreas.roehler@easy-emacs.de>]

On 06.05.2014 18:17, Joost Kremers wrote:
> Hi,
>
> Whenever I start an interactive Python session in Emacs, I get four
> empty prompts instead of one. That is, when I do `M-x run-python' (or
> start from a Python file with `C-c C-z'), the *Python* buffer looks like
> this:
>
> ,----
> | Python 2.7.3 (default, Feb 27 2014, 19:58:35)
> | Type "copyright", "credits" or "license" for more information.
> |
> | IPython 0.12.1 -- An enhanced Interactive Python.
> | ?         -> Introduction and overview of IPython's features.
> | %quickref -> Quick reference.
> | help      -> Python's own help system.
> | object?   -> Details about 'object', use 'object??' for extra details.
> |
> | In [1]:
> | In [2]:
> | In [3]:
> | In [4]:
> |
> `----
>
> I use elpy and IPython, but that doesn't make a difference. This is what
> I get when running an interactive Python shell with `emacs -Q':
>
> ,----
> | Python 2.7.3 (default, Feb 27 2014, 19:58:35)
> | [GCC 4.6.3] on linux2
> | Type "help", "copyright", "credits" or "license" for more information.
> | >>> >>> >>> >>>
> `----
>
> Note the four `>>>'.
>
> This is something that's been happening a while, and it's never really
> bothered me. However, the other day someone on Reddit asked the same
> question,[1] which prompted me to do some digging. I ran `run-python'
> though the debugger and it seems that those prompts are caused by the
> function `python-shell-send-setup-code', which sends the contents of the
> variables listed in the variable `python-shell-setup-codes' to the
> inferior python process when it's started. The default value of this
> option is:
>
> ,----
> | (python-shell-completion-setup-code python-ffap-setup-code python-eldoc-setup-code)
> `----
>
> Each of these variables contains some code which, when sent to the
> inferior python process, results in a new prompt being displayed, even
> though the actual command is not shown.
>
> Is this something that should be considered a bug? Can it be avoided
> somehow or should I simply live with it? (Which isn't very difficult, it
> doesn't seem to affect anything.)
>
> TIA
>
>
> [1] http://www.reddit.com/r/emacs/comments/24fy1q/help_get_rid_of_multiple_inputs_when_running_a/
>
>


That's because some some setup-code is sent to the python-process connected to the buffer.
Basically a filter could wipe them out. OTOH it's does no harm.

With python-mode.el and M-x python RET you should not have this.

BTW with ipython, you will see the prompt-counter raised and starting with [5] or so - for the very same reason.