bug#76487: 31.0.50; org babel source block :results code returns nil - pp possible culprit

[No Control To Edit]

problem:

when using ':results code' in an 'org babel source block' I get nil
instead of the result of last executed expression

setup:

Activate org mode on a buffer

    M-x org-mode

Insert this text

   #+BEGIN_SRC emacs-lisp :results code
     (+ 1 1)
   #+END_SRC

Do C-c C-c in source block and enter 'yes' to execute 


Actual results:

   #+RESULTS:
   #+begin_src emacs-lisp
    nil
   #+end_src


Expected results:

   #+RESULTS:
   #+begin_src emacs-lisp
    2
   #+end_src


Observations:

pp might be be causing the problem see: ob-emacs-lisp.el

when ':results code' used the  block contents are wrapped in pp i.e. (pp 
src-block-contents)

evaluating the following code in elisp returns

(pp (+ 1 1))
>> 2
>> nil




In GNU Emacs 31.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
 3.24.38, cairo version 1.16.0) of 2024-12-30 built on maestro
Repository revision: 7671d50b149edd9e19c29f5fa8ee71c01e2f583d
Repository branch: master
System Description: LMDE 6 (faye)

Configured using:
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Configured features:
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PNG RSVG SECCOMP SOUND THREADS TIFF TOOLKIT_SCROLL_BARS TREE_SITTER WEBP
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Load-path shadows:
None found.

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Memory information:
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 (string-bytes 1 2967838) (vectors 16 45383)
 (vector-slots 8 494459 18201) (floats 8 442 468)
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