Bug: :session results in unfriendly error reporting

[James Powell]

I write a deliberate syntax error into a code block:

: #+begin_src R :session
:   x <- 1
:   y xx z
: #+end_src

I put my cursor in there and C-c C-c.

What I expect: a gentle useful report about the error.
Maybe even org would move the cursor to the point of the
error in the org buffer.  If not, at least the buffer
"*Org-Babel Error Output*" will open and show me the error,
something like this (see also [1]),

: Error: unexpected symbol in:
: "x <- 1
: y xx"
: -UUU:@**--F2  *Org-Babel Error Output*   All L17    (Compilation etu) 
4:13PM 0.53 Mail --------------------------------------------------$

What happens instead:

- the *R* buffer is displayed.  It contains a long spammy traceback
  that has run off of the top of the screen.  To learn more I have to
  move the cursor into the *R* buffer and page back to the top of the
  traceback.

On the other hand, if I set ":session none", I get much friendlier
behavior.  The Error Output buffer opens with the simple error message
in it as I showed above when I use this source block:

: #+begin_src R :session none
:   x <- 1
:   y xx z
: #+end_src

I do not want to abandon :session because my code reads in a lot of
data to get started and I want my scripts, not my environment to be
"real" so I am not depending on R's ability to save and reload the
workspace at all [2] or on "Org's (clever and useful but) somewhat clunky
and inflexible method of passing data explicitly" [3].

Is there a way to get back to the "Error Output" buffer opening with a
simple message /while/ having :session being enabled?

thank you,
  James P.

References

[1] "Currently the only action Babel takes with STDERR is to display it in a
    pop-up buffer when code block evaluation fails" (Eric Schulte in 
2012, at
https://lists.gnu.org/archive/html/emacs-orgmode/2012-03/msg00057.html).

[2] « what will you save as your lasting record of what happened?
  [...[ As a beginning R user, it's OK to consider your environment
  [...]  "real."  However, in the long run, you'll be much better off
  if you consider your R scripts as "real." » (p. 111, Wickham, H. "R
  for data science : import, tidy, transform, visualize, and model
  data" O'Reilly Media, 2016).  To facilitate this, I have disabled
  'save workspace' permanently:
  : q <- function (save = "no", status = 0, runLast = TRUE)
  : .Internal(quit(save, status, runLast))

[3] «When I look at Org and think of "session-based" blocks, I see a
    potential big benefit in having multiple source-blocks throughout
    my document share the same session»
(https://lists.gnu.org/archive/html/emacs-orgmode/2011-06/msg00654.html,
    the only good hit for a search for "session Org-Babel Error Output" at
    https://lists.gnu.org/archive/html/emacs-orgmode/ as of
    [2021-08-15 Sun]).


--
James E. Powell, MS
Pronouns: he/him/his
Applied Physics PhD Candidate
Department of Physics
Portland State University
Home page: http://web.pdx.edu/~powellj
Office: SRTC 409B Phone: +1-503-725-8515