Bug: org-deadline drops warning periods from TIME [9.4.6 (9.4.6-10-gee652a-elpaplus @ /home/fap/.emacs.d/elpa/org-plus-contrib-20210712/)]

[erimius]

* Reproduction

Call ~org-deadline~ with a warning period like so:


(org-deadline nil "<2021-07-20 Tue -1d>")
   ;; => DEADLINE: <2021-07-20 Tue>

* Expected

Deadline gets added with the warning period provided.

* Actual

Deadline gets added without the provided warning period.

* Discussion

I've opened a Emacs Stackexchange question regarding this:
https://emacs.stackexchange.com/questions/66765/how-to-insert-an-org-deadline-from-lisp-with-a-warning-period/

And got told the following by Nick D:

#+begin_quote
I think this is a bug: the function ~org--deadline-or-schedule~ saves a
repeater (e.g ~+2d~ ) and adds it back at the end, but the regexp does
not match a warning period (e.g. ~-2d~) so it drops it. You should
probably report it with ~M-x org-submit-bug-report~.
#+end_quote

* Version info

Emacs  : GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version
3.24.20, cairo version 1.16.0)
 of 2020-09-19
Package: Org mode version 9.4.6 (9.4.6-10-gee652a-elpaplus @
/home/fap/.emacs.d/elpa/org-plus-contrib-20210712/)