6 files changed, 71 insertions, 31 deletions
diff --git a/doc/misc/gnus.texi b/doc/misc/gnus.texi
index 7d6fa4cb5ca..11bcfc16aef 100644
--- a/doc/misc/gnus.texi
+++ b/doc/misc/gnus.texi
@@ -2583,7 +2583,9 @@ with the process mark and then execute the command.
 @itemx M m
 @kindex M m @r{(Group)}
 @findex gnus-group-mark-group
-Set the mark on the current group (@code{gnus-group-mark-group}).
+Set the mark on the current group (@code{gnus-group-mark-group}).@*
+If @code{gnus-process-mark-toggle} is non-@code{nil}, toggle the
+existing process mark for the current group.
 
 @item M-#
 @kindex M-# @r{(Group)}
@@ -4043,7 +4045,9 @@ Toggle hiding empty topics
 @findex gnus-topic-mark-topic
 Mark all groups in the current topic with the process mark
 (@code{gnus-topic-mark-topic}).  This command works recursively on
-sub-topics unless given a prefix.
+sub-topics unless given a prefix.@*
+If @code{gnus-process-mark-toggle} is non-@code{nil}, toggle the
+existing process mark for the current topic.
 
 @item T M-#
 @kindex T M-# @r{(Topic)}
@@ -6618,13 +6622,15 @@ articles into the cache.  For more information,
 @kindex M P p @r{(Summary)}
 @findex gnus-summary-mark-as-processable
 Mark the current article with the process mark
-(@code{gnus-summary-mark-as-processable}).
-@findex gnus-summary-unmark-as-processable
+(@code{gnus-summary-mark-as-processable}).@*
+If @code{gnus-process-mark-toggle} is non-@code{nil}, toggle the
+existing process mark for the current article.
 
 @item M P u
 @itemx M-#
 @kindex M P u @r{(Summary)}
 @kindex M-# @r{(Summary)}
+@findex gnus-summary-unmark-as-processable
 Remove the process mark, if any, from the current article
 (@code{gnus-summary-unmark-as-processable}).
 
@@ -10568,7 +10574,9 @@ Pick the article or thread on the current line
 entire thread when used at the first article of the thread.  Otherwise,
 it selects just the article.  If given a numerical prefix, go to that
 thread or article and pick it.  (The line number is normally displayed
-at the beginning of the summary pick lines.)
+at the beginning of the summary pick lines.)  If
+@code{gnus-process-mark-toggle} is non-@code{nil}, this key will
+unpick an already picked article.
 
 @item @key{SPC}
 @kindex SPC @r{(Pick)}
diff --git a/etc/NEWS b/etc/NEWS
index d0f903ffa67..3658f7fcd53 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -836,6 +836,11 @@ tags to be considered as well.
 ** Gnus
 
 +++
+*** New user option 'gnus-process-mark-toggle'.
+If non-nil, the `#' command in the Group and Summary buffers will
+toggle instead of setting the process mark.
+
++++
 *** New user option 'gnus-registry-register-all'.
 If non-nil (the default), create registry entries for all messages.
 If nil, don't automatically create entries, they must be created
diff --git a/lisp/gnus/gnus-group.el b/lisp/gnus/gnus-group.el
index 8c62c9424de..06d1313d379 100644
--- a/lisp/gnus/gnus-group.el
+++ b/lisp/gnus/gnus-group.el
@@ -894,14 +894,14 @@ simple manner."
 	["Sort by real name" gnus-group-sort-selected-groups-by-real-name
 	 (not (gnus-topic-mode-p))])
        ("Mark"
-	["Mark group" gnus-group-mark-group
+	["Set/Toggle mark" gnus-group-mark-group
 	 (and (gnus-group-group-name)
 	      (not (memq (gnus-group-group-name) gnus-group-marked)))]
-	["Unmark group" gnus-group-unmark-group
+	["Remove mark" gnus-group-unmark-group
 	 (and (gnus-group-group-name)
 	      (memq (gnus-group-group-name) gnus-group-marked))]
-	["Unmark all" gnus-group-unmark-all-groups gnus-group-marked]
-	["Mark regexp..." gnus-group-mark-regexp t]
+	["Remove all marks" gnus-group-unmark-all-groups gnus-group-marked]
+	["Mark by regexp..." gnus-group-mark-regexp t]
 	["Mark region" gnus-group-mark-region :active mark-active]
 	["Mark buffer" gnus-group-mark-buffer t]
 	["Execute command" gnus-group-universal-argument
@@ -1865,7 +1865,7 @@ If FIRST-TOO, the current line is also eligible as a target."
     (forward-char (or (cdr (assq 'process gnus-group-mark-positions)) 2))
     (eq (char-after) gnus-process-mark)))
 
-(defun gnus-group-mark-group (n &optional unmark no-advance)
+(defun gnus-group-mark-group (n &optional unmark no-advance no-toggle)
   "Mark the current group."
   (interactive "p" gnus-group-mode)
   (let ((buffer-read-only nil)
@@ -1877,23 +1877,33 @@ If FIRST-TOO, the current line is also eligible as a target."
 	(beginning-of-line)
 	(forward-char (or (cdr (assq 'process gnus-group-mark-positions)) 2))
 	(delete-char 1)
-	(if unmark
-	    (progn
-	      (setq gnus-group-marked (delete group gnus-group-marked))
-              (insert-char ?\s 1 t))
-	   (setq gnus-group-marked
-		 (cons group (delete group gnus-group-marked)))
-	   (insert-char gnus-process-mark 1 t)))
+	(if (and gnus-process-mark-toggle (not no-toggle))
+	    (if (memq group gnus-group-marked)
+		(gnus-group-mark-update group t)
+	      (gnus-group-mark-update group))
+	  (gnus-group-mark-update group unmark)))
       (unless no-advance
 	(gnus-group-next-group 1))
       (cl-decf n))
     (gnus-group-position-point)
     n))
 
+(defun gnus-group-mark-update (n &optional unmark)
+  "Set the process mark on current group and update the group line."
+  (if unmark
+      (progn
+	(setq gnus-group-marked
+	      (delete n gnus-group-marked))
+	(insert-char ?\s 1 t))
+    (progn
+      (setq gnus-group-marked
+	    (cons n (delete n gnus-group-marked)))
+      (insert-char gnus-process-mark 1 t))))
+
 (defun gnus-group-unmark-group (n)
   "Remove the mark from the current group."
   (interactive "p" gnus-group-mode)
-  (gnus-group-mark-group n 'unmark)
+  (gnus-group-mark-group n 'unmark nil t)
   (gnus-group-position-point))
 
 (defun gnus-group-unmark-all-groups ()
@@ -1910,7 +1920,7 @@ If UNMARK, remove the mark instead."
   (let ((num (count-lines beg end)))
     (save-excursion
       (goto-char beg)
-      (- num (gnus-group-mark-group num unmark)))))
+      (- num (gnus-group-mark-group num unmark nil t)))))
 
 (defun gnus-group-mark-buffer (&optional unmark)
   "Mark all groups in the buffer.
@@ -1935,7 +1945,7 @@ If UNMARK, remove the mark instead."
 Return nil if the group isn't displayed."
   (if (gnus-group-goto-group group nil test-marked)
       (save-excursion
-	(gnus-group-mark-group 1 'unmark t)
+	(gnus-group-mark-group 1 'unmark t t)
 	t)
     (setq gnus-group-marked
 	  (delete group gnus-group-marked))
@@ -1945,7 +1955,7 @@ Return nil if the group isn't displayed."
   "Set the process mark on GROUP."
   (if (gnus-group-goto-group group)
       (save-excursion
-	(gnus-group-mark-group 1 nil t))
+	(gnus-group-mark-group 1 nil t t))
     (setq gnus-group-marked (cons group (delete group gnus-group-marked)))))
 
 (defun gnus-group-universal-argument (arg &optional _groups func)
diff --git a/lisp/gnus/gnus-sum.el b/lisp/gnus/gnus-sum.el
index aa4c7532878..48794ceb3fe 100644
--- a/lisp/gnus/gnus-sum.el
+++ b/lisp/gnus/gnus-sum.el
@@ -2774,7 +2774,7 @@ gnus-summary-show-article-from-menu-as-charset-%s" cs))))
 	 ["Hide marked" gnus-summary-limit-exclude-marks t]
 	 ["Show expunged" gnus-summary-limit-include-expunged t])
 	("Process Mark"
-	 ["Set mark" gnus-summary-mark-as-processable t]
+	 ["Set/Toggle mark" gnus-summary-mark-as-processable t]
 	 ["Remove mark" gnus-summary-unmark-as-processable t]
 	 ["Remove all marks" gnus-summary-unmark-all-processable t]
 	 ["Invert marks" gnus-uu-invert-processable t]
@@ -10951,10 +10951,14 @@ number of articles marked is returned."
 	  (n (abs n)))
       (while (and
 	      (> n 0)
-	      (if unmark
-		  (gnus-summary-remove-process-mark
-		   (gnus-summary-article-number))
-		(gnus-summary-set-process-mark (gnus-summary-article-number)))
+	      (let ((article (gnus-summary-article-number)))
+		(if unmark
+		    (gnus-summary-remove-process-mark article)
+		  (if gnus-process-mark-toggle
+		      (if (memq article gnus-newsgroup-processable)
+			  (gnus-summary-remove-process-mark article)
+			(gnus-summary-set-process-mark article))
+		    (gnus-summary-set-process-mark article))))
 	      (zerop (gnus-summary-next-subject (if backward -1 1) nil t)))
 	(setq n (1- n)))
       (when (/= 0 n)
diff --git a/lisp/gnus/gnus-topic.el b/lisp/gnus/gnus-topic.el
index b3d17bc03fb..c0484622f40 100644
--- a/lisp/gnus/gnus-topic.el
+++ b/lisp/gnus/gnus-topic.el
@@ -1112,7 +1112,7 @@ articles in the topic and its subtopics."
 	["Delete" gnus-topic-delete t]
 	["Rename..." gnus-topic-rename t]
 	["Create..." gnus-topic-create-topic t]
-	["Mark" gnus-topic-mark-topic t]
+	["Set/Toggle mark" gnus-topic-mark-topic t]
 	["Indent" gnus-topic-indent t]
 	["Sort" gnus-topic-sort-topics t]
 	["Previous topic" gnus-topic-goto-previous-topic t]
@@ -1436,7 +1436,7 @@ If PERMANENT, make it stay shown in subsequent sessions as well."
 	(setcar (cdr (cadr topic)) 'visible)
 	(gnus-group-list-groups)))))
 
-(defun gnus-topic-mark-topic (topic &optional unmark non-recursive)
+(defun gnus-topic-mark-topic (topic &optional unmark non-recursive no-toggle)
   "Mark all groups in the TOPIC with the process mark.
 If NON-RECURSIVE (which is the prefix) is t, don't mark its subtopics."
   (interactive
@@ -1450,8 +1450,13 @@ If NON-RECURSIVE (which is the prefix) is t, don't mark its subtopics."
       (let ((groups (gnus-topic-find-groups topic gnus-level-killed t nil
 					    (not non-recursive))))
 	(while groups
-	  (funcall (if unmark 'gnus-group-remove-mark 'gnus-group-set-mark)
-		   (gnus-info-group (nth 1 (pop groups)))))))))
+          (let ((group (gnus-info-group (nth 1 (pop groups)))))
+	    (if (and gnus-process-mark-toggle (not no-toggle))
+                (if (memq group gnus-group-marked)
+                    (gnus-group-remove-mark group )
+                  (gnus-group-set-mark group))
+              (if unmark (gnus-group-remove-mark group)
+                (gnus-group-set-mark group)))))))))
 
 (defun gnus-topic-unmark-topic (topic &optional _dummy non-recursive)
   "Remove the process mark from all groups in the TOPIC.
@@ -1462,7 +1467,7 @@ If NON-RECURSIVE (which is the prefix) is t, don't unmark its subtopics."
 	       gnus-topic-mode)
   (if (not topic)
       (call-interactively 'gnus-group-unmark-group)
-    (gnus-topic-mark-topic topic t non-recursive)))
+    (gnus-topic-mark-topic topic t non-recursive t)))
 
 (defun gnus-topic-get-new-news-this-topic (&optional n)
   "Check for new news in the current topic."
diff --git a/lisp/gnus/gnus.el b/lisp/gnus/gnus.el
index 7de1cd1ddb1..21b5f31c141 100644
--- a/lisp/gnus/gnus.el
+++ b/lisp/gnus/gnus.el
@@ -1183,6 +1183,14 @@ newsgroups."
   :group 'gnus-summary-marks
   :type 'character)
 
+(defcustom gnus-process-mark-toggle nil
+  "If non-nil the process mark command toggles the process mark."
+  :version "28.1"
+  :group 'gnus-summary
+  :group 'gnus-group-various
+  :group 'gnus-group-topic
+  :type 'boolean)
+
 (defcustom gnus-large-newsgroup 200
   "The number of articles which indicates a large newsgroup.
 If the number of articles in a newsgroup is greater than this value,