Bug: ob-python issue in Emacs 28 [9.4.4]

Bug: ob-python issue in Emacs 28 [9.4.4]

[Augusto Stoffel]

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In Emacs 28, `python-shell-send-string' prints an additional newline
between the prompt and output (among other things, so you can tell
whether or not the inferior process is busy at any given time).

However, this interferes with ob-python, see e.g.
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=50514

The attached patch indicates how to solve the problem.  As a permanent
solution, I would suggest to replace org-babel-chomp and actually strip
whitespace from both ends of the string outputted from the Python
interpreter.  (IPython even has a configuration option to add extra
whitespace before or after the output.)


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diff --git a/lisp/org/ob-python.el b/lisp/org/ob-python.el
index 7911205d08..e3714964b7 100644
--- a/lisp/org/ob-python.el
+++ b/lisp/org/ob-python.el
@@ -352,7 +352,7 @@ org-babel-python--send-string
 		   org-babel-python-eoe-indicator
 		   string-buffer))
 	(accept-process-output (get-buffer-process (current-buffer))))
-      (org-babel-chomp (substring string-buffer 0 (match-beginning 0))))))
+      (org-babel-chomp (substring string-buffer 1 (match-beginning 0))))))
 
 (defun org-babel-python-evaluate-session
     (session body &optional result-type result-params)

Re: Bug: ob-python issue in Emacs 28 [9.4.4]

[Jack Kamm]

Hi Augusto,

> In Emacs 28, `python-shell-send-string' prints an additional newline
> between the prompt and output (among other things, so you can tell
> whether or not the inferior process is busy at any given time).
>
> However, this interferes with ob-python, see e.g.
> https://debbugs.gnu.org/cgi/bugreport.cgi?bug=50514

Thanks for reporting this, and also for your recent improvements to
python.el.

Would you be willing to update your patch to use

(if (version< emacs-version "28") 0 1)

And add a commit message and changelog, so we can push it to master?

> As a permanent solution, I would suggest to replace org-babel-chomp
> and actually strip whitespace from both ends of the string outputted
> from the Python interpreter.  (IPython even has a configuration option
> to add extra whitespace before or after the output.)

I think this would be problematic, because then it would be impossible
to print output with leading or trailing whitespace, which it should be
possible to do.

Best,
Jack

Re: Bug: ob-python issue in Emacs 28 [9.4.4]

[Augusto Stoffel]

Hi Jack,

on a closer consideration, it's better to change python.el in such a way
that this problem vanishes.  I've submitted the patch to Emacs, so I
guess this issue can be considered closed.

Best,
Augusto