Hi everyone,
 a bug report:


Emacs  : GNU Emacs 27.2 (build 1, x86_64-unknown-openbsd, GTK+ Version 2.24.33)
 of 2021-04-20
Package: Org mode version 9.4.6 (release_9.4.6-4-g093c94 @ /home/roklein/.emacs.d/org-mode/lisp/)


When trying to run a table with missing values with ob-gnuplot.el
there's a “:missing value” option.  ob-gnuplot is supposed to put the
“value” into the place of empty cell values before calling on gnuplot.
It doesn't do this currently.  Bi-secting suggests,
“9209aa3c9d456bcfdd9d8cd223367f7cfb6b3231 is the first bad commit”:

--  commit 9209aa3c9d456bcfdd9d8cd223367f7cfb6b3231
--  Author: Nicolas Goaziou <mail@nicolasgoaziou.fr>
--  --  Sun Aug 24 01:31:56 2014 +0200
--
--  org-table: Use "ox.el" internally for radio tables


By my reading:
- in ob-gnuplot.el:org-babel-gnuplot-process-vars :missing variable is
  read, used in
- ob-gnuplot.el:org-babel-gnuplot-quote-tsv-field, called from
- ob-gnuplot.el:org-babel-gnuplot-table-to-data
- used in org-table.el:orgtbl-to-generic (as (part of the) :fmt param)
- which calls org-table--to-generic-cell
- which calle org-table.el:org-table--generic-apply
- which I don't understand

my dotemacs and a sample org file are attached.

When running the code (e.g. C-c C-c on the #+Call: line), temporary
files are created in /tmp/babel-<random>/gnuplot<other-random>.

These files should have "?" (as choosen :missing).  In the current
version there is nothing, so gnuplot uses up the values in the following
columns and the resulting graph is wrong.

Also, I couldn't find this in the manual, but there's a thread “using
gnuplot's "splot" and "every" comma nds on org-mode table” on the
mailing list (2013/09/23 - 3013/09/25) about the :missing feature.

Thanks for any help.

Best regards
Robert