From 635666e7bfca0117eeec6c769b02d71383607093 Mon Sep 17 00:00:00 2001
From: Lars Ingebrigtsen <larsi@gnus.org>
Date: Fri, 18 Sep 2020 13:28:12 +0200
Subject: [PATCH] Use a widget for the face link in Customize buffers

* doc/lispref/customize.texi (Common Keywords): Document it.

* lisp/cus-edit.el (custom-face-value-create): Use a widget
instead of a button so that TAB works (bug#20664).

* lisp/wid-edit.el (face-link): New widget.
(widget-face-link-action): New action.
---
 doc/lispref/customize.texi |  5 +++++
 lisp/cus-edit.el           | 10 +++++++---
 lisp/wid-edit.el           | 10 ++++++++++
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/doc/lispref/customize.texi b/doc/lispref/customize.texi
index c35444f5817..85912470795 100644
--- a/doc/lispref/customize.texi
+++ b/doc/lispref/customize.texi
@@ -124,6 +124,11 @@ Link to the documentation of a variable; @var{variable} is a string
 which specifies the name of the variable to describe with
 @code{describe-variable} when the user invokes this link.
 
+@item (face-link @var{face})
+Link to the documentation of a face; @var{face} is a string which
+specifies the name of the face to describe with @code{describe-face}
+when the user invokes this link.
+
 @item (custom-group-link @var{group})
 Link to another customization group.  Invoking it creates a new
 customization buffer for @var{group}.
diff --git a/lisp/cus-edit.el b/lisp/cus-edit.el
index 9626b3cf810..a62b623c44f 100644
--- a/lisp/cus-edit.el
+++ b/lisp/cus-edit.el
@@ -3571,9 +3571,13 @@ the present value is saved to its :shown-value property instead."
             buttons)
       ;; Face name (tag).
       (insert " ")
-      (insert-text-button tag
-                          'action (lambda (&rest _x)
-                                    (find-face-definition symbol)))
+      (push (widget-create-child-and-convert
+             widget 'face-link
+	     :button-face 'link
+             :tag tag
+             :action (lambda (&rest _x)
+                       (find-face-definition symbol)))
+            buttons)
       (insert
        (cond ((eq custom-buffer-style 'face) " ")
 	     ((string-match-p "face\\'" tag)   ":")
diff --git a/lisp/wid-edit.el b/lisp/wid-edit.el
index 5ac52777f84..13d850a57f5 100644
--- a/lisp/wid-edit.el
+++ b/lisp/wid-edit.el
@@ -1917,6 +1917,16 @@ If END is omitted, it defaults to the length of LIST."
   "Show the variable specified by WIDGET."
   (describe-variable (widget-value widget)))
 
+;;; The `face-link' Widget.
+
+(define-widget 'face-link 'link
+  "A link to an Emacs face."
+  :action 'widget-face-link-action)
+
+(defun widget-face-link-action (widget &optional _event)
+  "Show the variable specified by WIDGET."
+  (describe-face (widget-value widget)))
+
 ;;; The `file-link' Widget.
 
 (define-widget 'file-link 'link
-- 
2.39.5