From 783eca57159065ea575622b74e1446853f31621a Mon Sep 17 00:00:00 2001
From: Lars Ingebrigtsen <larsi@gnus.org>
Date: Sun, 14 Jul 2019 18:50:23 +0200
Subject: [PATCH] Make describe-face also output the version information

* lisp/help-fns.el (describe-variable-custom-version-info): Allow
taking a type as an optional input, so this can be used for faces,
too (bug#30527).

* lisp/faces.el (describe-face): Use this to output the version
information.
---
 lisp/faces.el    | 10 +++++++++-
 lisp/help-fns.el | 11 ++++++-----
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/lisp/faces.el b/lisp/faces.el
index f9e8c6c58b8..5193c216d0a 100644
--- a/lisp/faces.el
+++ b/lisp/faces.el
@@ -1416,6 +1416,8 @@ argument, prompt for a regular expression using `read-regexp'."
 	(dolist (face (face-list))
 	  (copy-face face face frame disp-frame)))))
 
+(declare-function describe-variable-custom-version-info "help-fns"
+                  (variable &optional type))
 
 (defun describe-face (face &optional frame)
   "Display the properties of face FACE on FRAME.
@@ -1428,6 +1430,7 @@ If FRAME is omitted or nil, use the selected frame."
   (interactive (list (read-face-name "Describe face"
                                      (or (face-at-point t) 'default)
                                      t)))
+  (require 'help-fns)
   (let* ((attrs '((:family . "Family")
 		  (:foundry . "Foundry")
 		  (:width . "Width")
@@ -1524,7 +1527,12 @@ If FRAME is omitted or nil, use the selected frame."
 			  (re-search-backward ": \\([^:]+\\)" nil t)
 			  (help-xref-button 1 'help-face attr)))
 		    (insert "\n")))))
-	    (terpri)))))))
+	    (terpri)
+            (let ((version-info (describe-variable-custom-version-info
+                                 f 'face)))
+              (when version-info
+                (insert version-info)
+                (terpri)))))))))
 
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
diff --git a/lisp/help-fns.el b/lisp/help-fns.el
index 39f701ae2a8..0b5c547d6b0 100644
--- a/lisp/help-fns.el
+++ b/lisp/help-fns.el
@@ -860,14 +860,15 @@ If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
                 (and (or any-symbol (boundp sym)) sym)))))
         0)))
 
-(defun describe-variable-custom-version-info (variable)
+(defun describe-variable-custom-version-info (variable &optional type)
   (let ((custom-version (get variable 'custom-version))
 	(cpv (get variable 'custom-package-version))
+        (type (or type "variable"))
 	(output nil))
     (if custom-version
 	(setq output
-	      (format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
-		      custom-version))
+	      (format "This %s was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
+                      type custom-version))
       (when cpv
 	(let* ((package (car-safe cpv))
 	       (version (if (listp (cdr-safe cpv))
@@ -877,11 +878,11 @@ If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
 	       (emacsv (cdr (assoc version pkg-versions))))
 	  (if (and package version)
 	      (setq output
-		    (format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
+		    (format (concat "This %s was introduced, or its default value was changed, in\nversion %s of the %s package"
 				    (if emacsv
 					(format " that is part of Emacs %s" emacsv))
 				    ".\n")
-			    version package))))))
+			    type version package))))))
     output))
 
 ;;;###autoload