[O] Bug: Org capture: Invalid use of ‘\’ in replacement text [9.1.14 (9.1.14-1049-g04641c-elpaplus @ /home/ionasal/.emacs.d/elpa/org-plus-contrib-20181203/)]

[Allen Li]

There's an escaping bug in Org capture:

1. emacs -Q
2. Evaluate:

(setq org-capture-templates
   '(("Z" "org-protocol capture" entry
      (file "/tmp/tmp")
      "* %?
%(let ((x \"%:annotation\")) (if (string= x \"\") \"\" (concat x
\"\\n\")))%i")))

3. Evaluate (require 'org-protocol)

4. Evaluate to simulate org protocol capture:

    (org-protocol-capture '(:template "Z" :body "foo\nbar\n"))

Causes error:

(error "Capture abort: (error Invalid use of ‘\\’ in replacement text)")

org-protocol is used in the example as that's where I encountered it,
but the bug is in org-capture proper.

Note that this works:

    (org-protocol-capture '(:template "Z" :body "foo"))

Emacs  : GNU Emacs 26.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.30)
 of 2018-07-05
Package: Org mode version 9.1.14 (9.1.14-1049-g04641c-elpaplus @
/home/ionasal/.emacs.d/elpa/org-plus-contrib-20181203/)