Subject: 28.0.50; [PATCH] Make minibuffer-depth-indicator-function a defcustom

From: Gabriel <[email-masked]>
Date: Fri, 19 Mar 2021 00:36:47 -0300

This simple patch makes 'minibuffer-depth-indicator-function' a
defcustom.

>From 6edb731766fa7fb34b62b3b1f9906d8c2119cb1c Mon Sep 17 00:00:00 2001
From: Gabriel do Nascimento Ribeiro <[email-masked]>
Date: Fri, 19 Mar 2021 00:09:43 -0300
Subject: [PATCH] * lisp/mb-depth.el: Make minibuffer-depth-indicator-function
 a defcustom

(minibuffer-depth-indicator-function): Make a defcustom.
---
 lisp/mb-depth.el | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/lisp/mb-depth.el b/lisp/mb-depth.el
index f9a24e34bf..71b4abb5cb 100644
--- a/lisp/mb-depth.el
+++ b/lisp/mb-depth.el
@@ -30,10 +30,12 @@
 
 ;;; Code:
 
-(defvar minibuffer-depth-indicator-function nil
+(defcustom minibuffer-depth-indicator-function nil
   "If non-nil, function to set up the minibuffer depth indicator.
 It is called with one argument, the minibuffer depth,
-and must return a string.")
+and must return a string."
+  :type 'function
+  :group 'minibuffer)
 
 (defface minibuffer-depth-indicator '((t :inherit highlight))
   "Face to use for minibuffer depth indicator."
-- 
2.27.0

There was a long discussion 14 years ago when mb-depth.el was
implemented about making it a defcustom or not:

[1] https://lists.gnu.org/archive/html/emacs-devel/2008-08/msg00025.html
[2] https://lists.gnu.org/archive/html/emacs-devel/2007-06/msg00304.html

These are the only references I could find about this topic. Perhaps
today the rationale for this decision is different and this patch can be
applied. If the decision is to keep it as a defvar, please close this
bug report.

Regards,
Gabriel