WIP on removing all internal encoding/decoding

14 files changed, 127 insertions, 217 deletions

diff --git a/lisp/gnus/gnus-agent.el b/lisp/gnus/gnus-agent.el
index 9f7d2c9df7d..f0b0a5dccd7 100644
--- a/lisp/gnus/gnus-agent.el
+++ b/lisp/gnus/gnus-agent.el
@@ -229,7 +229,7 @@ NOTES:
   "Cache of message subjects for spam messages.
 Actually a hash table holding subjects mapped to t.")
 (defvar gnus-agent-file-name nil)
-(defvar gnus-agent-file-coding-system 'raw-text)
+(defvar gnus-agent-file-coding-system 'utf-8-emacs)
 (defvar gnus-agent-file-loading-cache nil)
 (defvar gnus-agent-total-fetched-hashtb nil)
 (defvar gnus-agent-inhibit-update-total-fetched-for nil)
@@ -1327,7 +1327,10 @@ downloaded into the agent."
       (gnus-make-directory (file-name-directory file))
       (with-temp-file file
 	;; Emacs got problem to match non-ASCII group in multibyte buffer.
-	(mm-disable-multibyte)
+
+	;; FIXME: Is this still an issue now that group names are
+	;; always strings?
+	;(mm-disable-multibyte)
 	(when (file-exists-p file)
 	  (nnheader-insert-file-contents file)
 
@@ -1357,7 +1360,7 @@ downloaded into the agent."
       (gnus-make-directory (file-name-directory file))
       (with-temp-buffer
 	;; Emacs got problem to match non-ASCII group in multibyte buffer.
-	(mm-disable-multibyte)
+	;(mm-disable-multibyte)
 	(when (file-exists-p file)
 	  (nnheader-insert-file-contents file)
 
@@ -1434,7 +1437,7 @@ downloaded into the agent."
 			     (format " *Gnus agent %s history*"
 				     (gnus-agent-method)))))
 	  gnus-agent-history-buffers)
-    (mm-disable-multibyte) ;; everything is binary
+    ;(mm-disable-multibyte) ;; everything is binary
     (erase-buffer)
     (insert "\n")
     (let ((file (gnus-agent-lib-file "history")))
diff --git a/lisp/gnus/gnus-cus.el b/lisp/gnus/gnus-cus.el
index d56066e6168..5dc102ab771 100644
--- a/lisp/gnus/gnus-cus.el
+++ b/lisp/gnus/gnus-cus.el
@@ -388,7 +388,7 @@ category."))
 		     :tag  "topic parameters"
 		     "(gnus)Topic Parameters"))
     (widget-insert " for <")
-    (widget-insert (gnus-group-decoded-name (or group topic)))
+    (widget-insert (or group topic))
     (widget-insert "> and press ")
     (widget-create 'push-button
 		   :tag "done"
@@ -837,8 +837,7 @@ When called interactively, FILE defaults to the current score file.
 This can be changed using the `\\[gnus-score-change-score-file]' command."
   (interactive (list gnus-current-score-file))
   (unless file
-    (error "No score file for %s"
-           (gnus-group-decoded-name gnus-newsgroup-name)))
+    (error "No score file for %s" gnus-newsgroup-name))
   (let ((scores (gnus-score-load file))
 	(types (mapcar (lambda (entry)
 			 `(group :format "%v%h\n"
diff --git a/lisp/gnus/gnus-group.el b/lisp/gnus/gnus-group.el
index c757c82fbc8..ed81e12a085 100644
--- a/lisp/gnus/gnus-group.el
+++ b/lisp/gnus/gnus-group.el
@@ -479,7 +479,6 @@ simple manner."
 (defvar gnus-tmp-news-method)
 (defvar gnus-tmp-colon)
 (defvar gnus-tmp-news-server)
-(defvar gnus-tmp-decoded-group)
 (defvar gnus-tmp-header)
 (defvar gnus-tmp-process-marked)
 (defvar gnus-tmp-summary-live)
@@ -518,14 +517,9 @@ simple manner."
     (?T (gnus-range-length (cdr (assq 'tick gnus-tmp-marked))) ?d)
     (?i (+ (gnus-range-length (cdr (assq 'dormant gnus-tmp-marked)))
 	   (gnus-range-length (cdr (assq 'tick gnus-tmp-marked)))) ?d)
-    (?g (if (boundp 'gnus-tmp-decoded-group)
-	    gnus-tmp-decoded-group
-	  gnus-tmp-group)
-	?s)
+    (?g gnus-tmp-group ?s)
     (?G gnus-tmp-qualified-group ?s)
-    (?c (gnus-short-group-name (if (boundp 'gnus-tmp-decoded-group)
-				   gnus-tmp-decoded-group
-				 gnus-tmp-group))
+    (?c (gnus-short-group-name gnus-tmp-group)
 	?s)
     (?C gnus-tmp-comment ?s)
     (?D gnus-tmp-newsgroup-description ?s)
@@ -1398,8 +1392,7 @@ if it is a string, only list groups matching REGEXP."
                      ((functionp regexp) (funcall regexp group))))
           (add-text-properties
            (point) (prog1 (1+ (point))
-                     (insert " " mark "     *: "
-                             (gnus-group-decoded-name group)
+                     (insert " " mark " *: " group
                              "\n"))
            (list 'gnus-group group
                  'gnus-unread t
@@ -1508,8 +1501,6 @@ if it is a string, only list groups matching REGEXP."
   "Insert a group line in the group buffer."
   (let* ((gnus-tmp-method
 	  (gnus-server-get-method gnus-tmp-group gnus-tmp-method))
-	 (group-name-charset (gnus-group-name-charset gnus-tmp-method
-						      gnus-tmp-group))
 	 (gnus-tmp-active (gnus-active gnus-tmp-group))
 	 (gnus-tmp-number-total
 	  (if gnus-tmp-active
@@ -1528,16 +1519,13 @@ if it is a string, only list groups matching REGEXP."
 		((= gnus-tmp-level gnus-level-zombie) ?Z)
 		(t ?K)))
 	 (gnus-tmp-qualified-group
-	  (gnus-group-name-decode (gnus-group-real-name gnus-tmp-group)
-				  group-name-charset))
+	  (gnus-group-real-name gnus-tmp-group))
 	 (gnus-tmp-comment
 	  (or (gnus-group-get-parameter gnus-tmp-group 'comment t)
 	      gnus-tmp-group))
 	 (gnus-tmp-newsgroup-description
 	  (if gnus-description-hashtb
-	      (or (gnus-group-name-decode
-		   (gethash gnus-tmp-group gnus-description-hashtb)
-		   group-name-charset) "")
+	      (or (gethash gnus-tmp-group gnus-description-hashtb) "")
 	    ""))
 	 (gnus-tmp-moderated
 	  (if (and gnus-moderated-hashtb
@@ -1574,9 +1562,7 @@ if it is a string, only list groups matching REGEXP."
      (point)
      (prog1 (1+ (point))
        ;; Insert the text.
-       (let ((gnus-tmp-decoded-group (gnus-group-name-decode
-				      gnus-tmp-group group-name-charset)))
-	 (eval gnus-group-line-format-spec)))
+       (eval gnus-group-line-format-spec))
      `(gnus-group ,gnus-tmp-group
 		  gnus-unread ,(if (numberp number)
 				   (string-to-number gnus-tmp-number-of-unread)
@@ -2166,6 +2152,9 @@ Non-ASCII group names are allowed.  The arguments are the same as
 `gnus-active-hashtb' and `gnus-group-history' respectively if
 they are omitted.  Can handle COLLECTION as a list, hash table,
 or vector."
+  ;; This function is a little more complicated for backwards
+  ;; compatibility.  In theory, `collection' will only ever be a list
+  ;; or a hash table, and the group names will all be fully decoded.
   (or collection (setq collection gnus-active-hashtb))
   (let* ((choices
 	  (mapcar
@@ -2726,13 +2715,13 @@ The user will be prompted for GROUP."
   (interactive (list (gnus-group-completing-read)))
   (gnus-group-make-group (gnus-group-real-name group)
 			 (gnus-group-server group)
-			 nil nil t))
+			 nil nil))
 
-(defun gnus-group-make-group (name &optional method address args encoded)
+(defun gnus-group-make-group (name &optional method address args)
   "Add a new newsgroup.
 The user will be prompted for a NAME, for a select METHOD, and an
 ADDRESS.  NAME should be a human-readable string (i.e., not be encoded
-even if it contains non-ASCII characters) unless ENCODED is non-nil.
+even if it contains non-ASCII characters).
 
 If the backend supports it, the group will also be created on the
 server."
@@ -2743,10 +2732,6 @@ server."
 
   (when (stringp method)
     (setq method (or (gnus-server-to-method method) method)))
-  (unless encoded
-    (setq name (encode-coding-string
-		name
-		(gnus-group-name-charset method name))))
   (let* ((meth (gnus-method-simplify
 		(when (and method
 			   (not (gnus-server-equal method gnus-select-method)))
@@ -2755,7 +2740,7 @@ server."
 	 (nname (if method (gnus-group-prefixed-name name meth) name))
 	 backend info)
     (when (gnus-group-entry nname)
-      (error "Group %s already exists" (gnus-group-decoded-name nname)))
+      (error "Group %s already exists" nname))
     ;; Subscribe to the new group.
     (gnus-group-change-level
      (setq info (list t nname gnus-level-default-subscribed nil nil meth))
@@ -3076,8 +3061,7 @@ If called with a prefix argument, ask for the file type."
 	 (coding (gnus-group-name-charset method name)))
     (setcar (cdr method) (encode-coding-string file coding))
     (gnus-group-make-group
-     (encode-coding-string (gnus-group-real-name name) coding)
-     method nil nil t)))
+     (gnus-group-real-name name) method nil nil)))
 
 (defvar nnweb-type-definition)
 (defvar gnus-group-web-type-history nil)
@@ -4458,9 +4442,9 @@ and the second element is the address."
 		   (prin1-to-string (car method)))
 		 (and (consp method)
 		      (nth 1 (gnus-info-method info)))
-		 nil t)
+		 nil)
 	      ;; It's a native group.
-	      (gnus-group-make-group (gnus-info-group info) nil nil nil t)))
+	      (gnus-group-make-group (gnus-info-group info) nil nil nil)))
 	  (gnus-message 6 "Note: New group created")
 	  (setq entry
 		(gnus-group-entry (gnus-group-prefixed-name
diff --git a/lisp/gnus/gnus-srvr.el b/lisp/gnus/gnus-srvr.el
index 76a0f7d0fdb..2328f1da163 100644
--- a/lisp/gnus/gnus-srvr.el
+++ b/lisp/gnus/gnus-srvr.el
@@ -859,12 +859,7 @@ claim them."
 			   ((= level gnus-level-zombie) ?Z)
 			   (t ?K)))
 			(max 0 (- (1+ (cddr group)) (cadr group)))
-			;; Don't decode if name is ASCII
-			(if (eq (detect-coding-string name t) 'undecided)
-			    name
-			  (decode-coding-string
-			   name
-			   (inline (gnus-group-name-charset method name)))))))
+			name)))
 	     (list 'gnus-group name)
 	     )))
 	(switch-to-buffer (current-buffer)))
diff --git a/lisp/gnus/gnus-start.el b/lisp/gnus/gnus-start.el
index 2f8a260bf13..9a93ad05498 100644
--- a/lisp/gnus/gnus-start.el
+++ b/lisp/gnus/gnus-start.el
@@ -1834,17 +1834,22 @@ The info element is shared with the same element of
 	(if (setq rest (member method methods))
 	    (gnus-info-set-method info (car rest))
 	  (push method methods)))
+      ;; Check for encoded group names and decode them.
+      (when (string-match-p "[^\000-\177]" (setq gname (car info)))
+	(let ((decoded (gnus-group-decoded-name gname)))
+	 (setf gname decoded
+	       (car info) decoded)))
       ;; Check for duplicates.
-      (if (gethash (car info) gnus-newsrc-hashtb)
+      (if (gethash gname gnus-newsrc-hashtb)
 	  ;; Remove this entry from the alist.
 	  (setcdr alist (cddr alist))
 	(puthash
-	 (car info)
+	 gname
 	 ;; Preserve number of unread articles in groups.
-	 (list (and ohashtb (car (gethash (car info) ohashtb)))
+	 (list (and ohashtb (car (gethash gname ohashtb)))
 	       info)
 	 gnus-newsrc-hashtb)
-	(push (car info) gnus-group-list))
+	(push gname gnus-group-list))
       (setq alist (cdr alist)))
     (setq gnus-group-list (nreverse gnus-group-list))
     ;; Make the same select-methods in `gnus-server-alist' identical
@@ -2150,9 +2155,7 @@ The info element is shared with the same element of
 				      (cond ((numberp group)
 					     (number-to-string group))
 					    ((symbolp group)
-					     (encode-coding-string
-					      (symbol-name group)
-					      'latin-1))
+					     (symbol-name group))
 					    ((stringp group)
 					     group)))))
 		     (numberp (setq max (read cur)))
@@ -2918,10 +2921,6 @@ SPECIFIC-VARIABLES, or those in `gnus-variable-list'."
       (setq default-directory (file-name-directory buffer-file-name))
       (buffer-disable-undo)
       (erase-buffer)
-      ;; Use a unibyte buffer since group names are unibyte strings;
-      ;; in particular, non-ASCII group names are the ones encoded by
-      ;; a certain coding system.
-      (mm-disable-multibyte)
       ;; Write options.
       (when gnus-newsrc-options
 	(insert gnus-newsrc-options))
diff --git a/lisp/gnus/gnus-sum.el b/lisp/gnus/gnus-sum.el
index b8aa302f11a..bc367978b2d 100644
--- a/lisp/gnus/gnus-sum.el
+++ b/lisp/gnus/gnus-sum.el
@@ -3511,8 +3511,7 @@ value of GROUP, and puts the buffer in `gnus-summary-mode'.
 
 Returns non-nil if the setup was successful."
   (let ((buffer (gnus-summary-buffer-name group))
-	(dead-name (concat "*Dead Summary "
-			   (gnus-group-decoded-name group) "*")))
+	(dead-name (concat "*Dead Summary " group "*")))
     ;; If a dead summary buffer exists, we kill it.
     (when (gnus-buffer-live-p dead-name)
       (gnus-kill-buffer dead-name))
@@ -3988,8 +3987,7 @@ If SELECT-ARTICLES, only select those articles from GROUP."
   ;;  (when (and (not (gnus-group-native-p group))
   ;;	     (not (gethash group gnus-newsrc-hashtb)))
   ;;    (error "Dead non-native groups can't be entered"))
-  (gnus-message 7 "Retrieving newsgroup: %s..."
-		(gnus-group-decoded-name group))
+  (gnus-message 7 "Retrieving newsgroup: %s..." group)
   (let* ((new-group (gnus-summary-setup-buffer group))
 	 (quit-config (gnus-group-quit-config group))
 	 (did-select (and new-group (gnus-select-newsgroup
@@ -4020,8 +4018,7 @@ If SELECT-ARTICLES, only select those articles from GROUP."
 	      (gnus-group-next-unread-group 1))
 	  (gnus-handle-ephemeral-exit quit-config)))
       (if (null (gnus-list-of-unread-articles group))
-	  (gnus-message 3 "Group %s contains no messages"
-			(gnus-group-decoded-name group))
+	  (gnus-message 3 "Group %s contains no messages" group)
 	(gnus-message 3 "Can't select group"))
       nil)
      ;; The user did a `C-g' while prompting for number of articles,
@@ -5620,25 +5617,24 @@ or a straight list of headers."
 
 (defun gnus-fetch-headers (articles &optional limit force-new dependencies)
   "Fetch headers of ARTICLES."
-  (let ((name (gnus-group-decoded-name gnus-newsgroup-name)))
-    (gnus-message 7 "Fetching headers for %s..." name)
-    (prog1
-	(if (eq 'nov
-		(setq gnus-headers-retrieved-by
-		      (gnus-retrieve-headers
-		       articles gnus-newsgroup-name
-		       (or limit
-			   ;; We might want to fetch old headers, but
-			   ;; not if there is only 1 article.
-			   (and (or (and
-				     (not (eq gnus-fetch-old-headers 'some))
-				     (not (numberp gnus-fetch-old-headers)))
-				    (> (length articles) 1))
-				gnus-fetch-old-headers)))))
-	    (gnus-get-newsgroup-headers-xover
-	     articles force-new dependencies gnus-newsgroup-name t)
-	  (gnus-get-newsgroup-headers dependencies force-new))
-      (gnus-message 7 "Fetching headers for %s...done" name))))
+  (gnus-message 7 "Fetching headers for %s..." gnus-newsgroup-name)
+  (prog1
+      (if (eq 'nov
+	      (setq gnus-headers-retrieved-by
+		    (gnus-retrieve-headers
+		     articles gnus-newsgroup-name
+		     (or limit
+			 ;; We might want to fetch old headers, but
+			 ;; not if there is only 1 article.
+			 (and (or (and
+				   (not (eq gnus-fetch-old-headers 'some))
+				   (not (numberp gnus-fetch-old-headers)))
+				  (> (length articles) 1))
+			      gnus-fetch-old-headers)))))
+	  (gnus-get-newsgroup-headers-xover
+	   articles force-new dependencies gnus-newsgroup-name t)
+	(gnus-get-newsgroup-headers dependencies force-new))
+    (gnus-message 7 "Fetching headers for %s...done" gnus-newsgroup-name)))
 
 (defun gnus-select-newsgroup (group &optional read-all select-articles)
   "Select newsgroup GROUP.
@@ -5651,13 +5647,12 @@ If SELECT-ARTICLES, only select those articles from GROUP."
 	      t
 	    gnus-summary-ignore-duplicates))
 	 (info (nth 1 entry))
-	 charset articles fetched-articles cached)
+	 articles fetched-articles cached)
 
     (unless (gnus-check-server
 	     (set (make-local-variable 'gnus-current-select-method)
 		  (gnus-find-method-for-group group)))
       (error "Couldn't open server"))
-    (setq charset (gnus-group-name-charset gnus-current-select-method group))
 
     (or (and entry (not (eq (car entry) t))) ; Either it's active...
 	(gnus-activate-group group)	; Or we can activate it...
@@ -5665,16 +5660,12 @@ If SELECT-ARTICLES, only select those articles from GROUP."
 	  (when (derived-mode-p 'gnus-summary-mode)
 	    (gnus-kill-buffer (current-buffer)))
 	  (error
-	   "Couldn't activate group %s: %s"
-	   (decode-coding-string group charset)
-	   (decode-coding-string (gnus-status-message group) charset))))
+	   "Couldn't activate group %s: %s" group (gnus-status-message group))))
 
     (unless (gnus-request-group group t nil info)
       (when (derived-mode-p 'gnus-summary-mode)
 	(gnus-kill-buffer (current-buffer)))
-      (error "Couldn't request group %s: %s"
-	     (decode-coding-string group charset)
-	     (decode-coding-string (gnus-status-message group) charset)))
+      (error "Couldn't request group %s: %s" group (gnus-status-message group)))
 
     (when (and gnus-agent
 	       (gnus-active group))
@@ -5942,13 +5933,11 @@ If SELECT-ARTICLES, only select those articles from GROUP."
 			   (if only-read-p
 			       (format
 				"How many articles from %s (available %d, default %d): "
-				(gnus-group-real-name
-				 (gnus-group-decoded-name gnus-newsgroup-name))
+				(gnus-group-real-name gnus-newsgroup-name)
 				number default)
 			     (format
 			      "How many articles from %s (%d default): "
-			      (gnus-group-real-name
-			       (gnus-group-decoded-name gnus-newsgroup-name))
+			      (gnus-group-real-name gnus-newsgroup-name)
 			      default))
 			   nil
 			   nil
@@ -5960,8 +5949,7 @@ If SELECT-ARTICLES, only select those articles from GROUP."
 			 (read-string
 			  (format "%s %s (%d scored, %d total): "
 				  "How many articles from"
-				  (gnus-group-decoded-name
-				   (gnus-group-real-name gnus-newsgroup-name))
+				  (gnus-group-real-name gnus-newsgroup-name)
 				  scored number))))
 		    (if (string-match "^[ \t]*$" input)
 			number input)))
@@ -6203,8 +6191,7 @@ If WHERE is `summary', the summary mode line format will be used."
 			 (intern
 			  (format "gnus-%s-mode-line-format-spec" where))))
 	       (gnus-tmp-group-name (gnus-mode-string-quote
-				     (gnus-group-decoded-name
-				      gnus-newsgroup-name)))
+				     gnus-newsgroup-name))
 	       (gnus-tmp-article-number (or gnus-current-article 0))
 	       (gnus-tmp-unread gnus-newsgroup-unreads)
 	       (gnus-tmp-unread-and-unticked (length gnus-newsgroup-unreads))
@@ -7928,11 +7915,11 @@ If BACKWARD, the previous article is selected instead of the next."
 		      (not (gnus-ephemeral-group-p gnus-newsgroup-name)))
 		 (format " (Type %s for %s [%s])"
 			 (single-key-description cmd)
-			 (gnus-group-decoded-name group)
+			 group
 			 (gnus-group-unread group))
 	       (format " (Type %s to exit %s)"
 		       (single-key-description cmd)
-		       (gnus-group-decoded-name gnus-newsgroup-name)))))
+		       gnus-newsgroup-name))))
       ;; Confirm auto selection.
       (setq key (car (setq keve (gnus-read-event-char prompt)))
 	    ended t)
@@ -10039,7 +10026,7 @@ ACTION can be either `move' (the default), `crosspost' or `copy'."
 	(copy-buf (save-excursion
 		    (nnheader-set-temp-buffer " *copy article*")))
 	art-group to-method new-xref article to-groups
-	articles-to-update-marks encoded)
+	articles-to-update-marks)
     (unless (assq action names)
       (error "Unknown action %s" action))
     ;; Read the newsgroup name.
@@ -10061,22 +10048,12 @@ ACTION can be either `move' (the default), `crosspost' or `copy'."
 			  (symbol-value
 			   (intern (format "gnus-current-%s-group" action)))
 			  articles prefix)
-	    encoded to-newsgroup
 	    to-method (gnus-server-to-method (gnus-group-method to-newsgroup)))
-      (set (intern (format "gnus-current-%s-group" action))
-	   (decode-coding-string
-	    to-newsgroup
-	    (gnus-group-name-charset to-method to-newsgroup))))
+      (set (intern (format "gnus-current-%s-group" action)) to-newsgroup))
     (unless to-method
       (setq to-method (or select-method
 			  (gnus-server-to-method
 			   (gnus-group-method to-newsgroup)))))
-    (setq to-newsgroup
-	  (or encoded
-	      (and to-newsgroup
-		   (encode-coding-string
-		    to-newsgroup
-		    (gnus-group-name-charset to-method to-newsgroup)))))
     ;; Check the method we are to move this article to...
     (unless (gnus-check-backend-function
 	     'request-accept-article (car to-method))
@@ -10086,7 +10063,7 @@ ACTION can be either `move' (the default), `crosspost' or `copy'."
     (gnus-message 6 "%s to %s: %s..."
 		  (caddr (assq action names))
 		  (or (car select-method)
-		      (gnus-group-decoded-name to-newsgroup))
+		      to-newsgroup)
 		  articles)
     ;; This `while' is not equivalent to a `dolist' (bug#33653#134).
     (while articles
@@ -12398,27 +12375,23 @@ save those articles instead."
            (t
             (gnus-completing-read
              prom (nreverse split-name) nil nil 'gnus-group-history))))
-         (to-method (gnus-server-to-method (gnus-group-method to-newsgroup)))
-	 encoded)
+         (to-method (gnus-server-to-method (gnus-group-method to-newsgroup))))
     (when to-newsgroup
       (if (or (string= to-newsgroup "")
 	      (string= to-newsgroup prefix))
 	  (setq to-newsgroup default))
       (unless to-newsgroup
-	(user-error "No group name entered"))
-      (setq encoded (encode-coding-string
-		     to-newsgroup
-		     (gnus-group-name-charset to-method to-newsgroup)))
-      (or (gnus-active encoded)
-	  (gnus-activate-group encoded nil nil to-method)
+	(error "No group name entered"))
+      (or (gnus-active to-newsgroup)
+	  (gnus-activate-group to-newsgroup nil nil to-method)
 	  (if (gnus-y-or-n-p (format "No such group: %s.  Create it? "
 				     to-newsgroup))
-	      (or (and (gnus-request-create-group encoded to-method)
-		       (gnus-activate-group encoded nil nil to-method)
-		       (gnus-subscribe-group encoded))
+	      (or (and (gnus-request-create-group to-newsgroup to-method)
+		       (gnus-activate-group to-newsgroup nil nil to-method)
+		       (gnus-subscribe-group to-newsgroup))
 		  (error "Couldn't create group %s" to-newsgroup)))
-	  (user-error "No such group: %s" to-newsgroup))
-      encoded)))
+	  (error "No such group: %s" to-newsgroup))
+      to-newsgroup)))
 
 (defvar gnus-summary-save-parts-counter)
 (declare-function mm-uu-dissect "mm-uu" (&optional noheader mime-type))
@@ -13085,7 +13058,7 @@ If ALL is a number, fetch this number of articles."
 		      (read-string
 		       (format
 			"How many articles from %s (%s %d): "
-			(gnus-group-decoded-name gnus-newsgroup-name)
+			gnus-newsgroup-name
 			(if initial "max" "default")
 			len)
 		       nil nil
diff --git a/lisp/gnus/gnus-util.el b/lisp/gnus/gnus-util.el
index 6b0f29b0afb..b110f91f1e7 100644
--- a/lisp/gnus/gnus-util.el
+++ b/lisp/gnus/gnus-util.el
@@ -1175,16 +1175,10 @@ ARG is passed to the first function."
 	(throw 'found nil)))
     t))
 
-;; gnus.el requires mm-util.
-(declare-function mm-disable-multibyte "mm-util")
-
 (defun gnus-write-active-file (file hashtb &optional full-names)
-  ;; `coding-system-for-write' should be `raw-text' or equivalent.
   (let ((coding-system-for-write nnmail-active-file-coding-system))
     (with-temp-file file
-      ;; The buffer should be in the unibyte mode because group names
-      ;; are ASCII text or encoded non-ASCII text (i.e., unibyte).
-      (mm-disable-multibyte)
+      (insert (format ";; -*- encoding: %s; -*-\n\n" coding-system-for-write))
       (maphash
        (lambda (group active)
 	 (when active
diff --git a/lisp/gnus/gnus.el b/lisp/gnus/gnus.el
index 989347c9fd1..0134a12ec17 100644
--- a/lisp/gnus/gnus.el
+++ b/lisp/gnus/gnus.el
@@ -3455,11 +3455,9 @@ server is native)."
   "Return the prefix of the current group name."
   (< 0 (length (gnus-group-real-prefix group))))
 
-(declare-function gnus-group-decoded-name "gnus-group" (string))
-
 (defun gnus-summary-buffer-name (group)
   "Return the summary buffer name of GROUP."
-  (concat "*Summary " (gnus-group-decoded-name group) "*"))
+  (concat "*Summary " group "*"))
 
 (defun gnus-group-method (group)
   "Return the server or method used for selecting GROUP.
diff --git a/lisp/gnus/nnagent.el b/lisp/gnus/nnagent.el
index 64f3a861810..f0baf99bd4c 100644
--- a/lisp/gnus/nnagent.el
+++ b/lisp/gnus/nnagent.el
@@ -117,18 +117,17 @@
   (gnus-request-accept-article "nndraft:queue" nil t t))
 
 (deffoo nnagent-request-set-mark (group action server)
-  (mm-with-unibyte-buffer
-    (insert "(gnus-agent-synchronize-group-flags \""
-	    group
-	    "\" '")
-    (gnus-pp action)
-    (insert " \""
-	    (gnus-method-to-server gnus-command-method)
-	    "\"")
-    (insert ")\n")
-    (let ((coding-system-for-write nnheader-file-coding-system))
-      (write-region (point-min) (point-max) (gnus-agent-lib-file "flags")
-		    t 'silent)))
+  (insert "(gnus-agent-synchronize-group-flags \""
+	  group
+	  "\" '")
+  (gnus-pp action)
+  (insert " \""
+	  (gnus-method-to-server gnus-command-method)
+	  "\"")
+  (insert ")\n")
+  (let ((coding-system-for-write nnheader-file-coding-system))
+    (write-region (point-min) (point-max) (gnus-agent-lib-file "flags")
+		  t 'silent))
   ;; Also set the marks for the original back end that keeps marks in
   ;; the local system.
   (let ((gnus-agent nil))
diff --git a/lisp/gnus/nnheader.el b/lisp/gnus/nnheader.el
index 090b8420842..697a6c36972 100644
--- a/lisp/gnus/nnheader.el
+++ b/lisp/gnus/nnheader.el
@@ -30,7 +30,6 @@
 
 (defvar nnmail-extra-headers)
 (defvar gnus-newsgroup-name)
-(defvar nnheader-file-coding-system)
 (defvar jka-compr-compression-info-list)
 
 ;; Requiring `gnus-util' at compile time creates a circular
@@ -566,7 +565,8 @@ the line could be found."
 
 (defvar nntp-server-buffer nil)
 (defvar nntp-process-response nil)
-
+(defvar nnheader-file-coding-system 'undecided
+  "Coding system used in file backends of Gnus.")
 (defvar nnheader-callback-function nil)
 
 (defun nnheader-init-server-buffer ()
@@ -938,9 +938,6 @@ first.  Otherwise, find the newest one, though it may take a time."
       (when (string-match (car ange-ftp-path-format) path)
 	(ange-ftp-re-read-dir path)))))
 
-(defvar nnheader-file-coding-system 'raw-text
-  "Coding system used in file backends of Gnus.")
-
 (defun nnheader-insert-file-contents (filename &optional visit beg end replace)
   "Like `insert-file-contents', q.v., but only reads in the file.
 A buffer may be modified in several ways after reading into the buffer due
diff --git a/lisp/gnus/nnimap.el b/lisp/gnus/nnimap.el
index ac1d28644f7..5dce7b4ce46 100644
--- a/lisp/gnus/nnimap.el
+++ b/lisp/gnus/nnimap.el
@@ -119,12 +119,6 @@ some servers.")
 
 (defvoo nnimap-namespace nil)
 
-(defun nnimap-decode-gnus-group (group)
-  (decode-coding-string group 'utf-8))
-
-(defun nnimap-encode-gnus-group (group)
-  (encode-coding-string group 'utf-8))
-
 (defvoo nnimap-fetch-partial-articles nil
   "If non-nil, Gnus will fetch partial articles.
 If t, Gnus will fetch only the first part.  If a string, it
@@ -209,8 +203,6 @@ textual parts.")
     (format "%s" (nreverse params))))
 
 (deffoo nnimap-retrieve-headers (articles &optional group server _fetch-old)
-  (when group
-    (setq group (nnimap-decode-gnus-group group)))
   (with-current-buffer nntp-server-buffer
     (erase-buffer)
     (when (nnimap-change-group group server)
@@ -630,8 +622,6 @@ textual parts.")
   nnimap-status-string)
 
 (deffoo nnimap-request-article (article &optional group server to-buffer)
-  (when group
-    (setq group (nnimap-decode-gnus-group group)))
   (with-current-buffer nntp-server-buffer
     (let ((result (nnimap-change-group group server))
 	  parts structure)
@@ -663,8 +653,6 @@ textual parts.")
 	    (cons group article)))))))
 
 (deffoo nnimap-request-head (article &optional group server to-buffer)
-  (when group
-    (setq group (nnimap-decode-gnus-group group)))
   (when (nnimap-change-group group server)
     (with-current-buffer (nnimap-buffer)
       (when (stringp article)
@@ -682,8 +670,6 @@ textual parts.")
 	    (cons group article)))))))
 
 (deffoo nnimap-request-articles (articles &optional group server)
-  (when group
-    (setq group (nnimap-decode-gnus-group group)))
   (with-current-buffer nntp-server-buffer
     (let ((result (nnimap-change-group group server)))
       (when result
@@ -833,7 +819,6 @@ textual parts.")
     (nreverse parts)))
 
 (deffoo nnimap-request-group (group &optional server dont-check info)
-  (setq group (nnimap-decode-gnus-group group))
   (let ((result (nnimap-change-group
 		 ;; Don't SELECT the group if we're going to select it
 		 ;; later, anyway.
@@ -860,11 +845,10 @@ textual parts.")
 			(- (cdr active) (car active))
 			(car active)
 			(cdr active)
-			(nnimap-encode-gnus-group group)))
+			group))
 	t))))
 
 (deffoo nnimap-request-group-scan (group &optional server info)
-  (setq group (nnimap-decode-gnus-group group))
   (when (nnimap-change-group nil server)
     (let (marks high low)
       (with-current-buffer (nnimap-buffer)
@@ -896,23 +880,20 @@ textual parts.")
 	(insert
 	 (format
 	  "211 %d %d %d %S\n" (1+ (- high low)) low high
-	  (nnimap-encode-gnus-group group)))
+	  group))
 	t))))
 
 (deffoo nnimap-request-create-group (group &optional server _args)
-  (setq group (nnimap-decode-gnus-group group))
   (when (nnimap-change-group nil server)
     (with-current-buffer (nnimap-buffer)
       (car (nnimap-command "CREATE %S" (nnimap-group-to-imap group))))))
 
 (deffoo nnimap-request-delete-group (group &optional _force server)
-  (setq group (nnimap-decode-gnus-group group))
   (when (nnimap-change-group nil server)
     (with-current-buffer (nnimap-buffer)
       (car (nnimap-command "DELETE %S" (nnimap-group-to-imap group))))))
 
 (deffoo nnimap-request-rename-group (group new-name &optional server)
-  (setq group (nnimap-decode-gnus-group group))
   (when (nnimap-change-group nil server)
     (with-current-buffer (nnimap-buffer)
       (nnimap-unselect-group)
@@ -927,7 +908,6 @@ textual parts.")
   (nnimap-command "EXAMINE DOES.NOT.EXIST"))
 
 (deffoo nnimap-request-expunge-group (group &optional server)
-  (setq group (nnimap-decode-gnus-group group))
   (when (nnimap-change-group group server)
     (with-current-buffer (nnimap-buffer)
       (car (nnimap-command "EXPUNGE")))))
@@ -956,9 +936,6 @@ textual parts.")
 (deffoo nnimap-request-move-article (article group server accept-form
 					     &optional _last
 					     internal-move-group)
-  (setq group (nnimap-decode-gnus-group group))
-  (when internal-move-group
-    (setq internal-move-group (nnimap-decode-gnus-group internal-move-group)))
   (with-temp-buffer
     (mm-disable-multibyte)
     (when (funcall (if internal-move-group
@@ -992,7 +969,6 @@ textual parts.")
 	    result))))))
 
 (deffoo nnimap-request-expire-articles (articles group &optional server force)
-  (setq group (nnimap-decode-gnus-group group))
   (cond
    ((null articles)
     nil)
@@ -1141,8 +1117,6 @@ If LIMIT, first try to limit the search to the N last articles."
                                 "delete this article now"))))))
 
 (deffoo nnimap-request-scan (&optional group server)
-  (when group
-    (setq group (nnimap-decode-gnus-group group)))
   (when (and (nnimap-change-group nil server)
 	     nnimap-inbox
 	     nnimap-split-methods)
@@ -1161,7 +1135,6 @@ If LIMIT, first try to limit the search to the N last articles."
     flags))
 
 (deffoo nnimap-request-update-group-status (group status &optional server)
-  (setq group (nnimap-decode-gnus-group group))
   (when (nnimap-change-group nil server)
     (let ((command (assoc
 		    status
@@ -1172,7 +1145,6 @@ If LIMIT, first try to limit the search to the N last articles."
 	  (nnimap-command "%s %S" (cadr command) (nnimap-group-to-imap group)))))))
 
 (deffoo nnimap-request-set-mark (group actions &optional server)
-  (setq group (nnimap-decode-gnus-group group))
   (when (nnimap-change-group group server)
     (let (sequence)
       (with-current-buffer (nnimap-buffer)
@@ -1207,8 +1179,7 @@ If LIMIT, first try to limit the search to the N last articles."
 	    ;; that's determined by the IMAP server later.  So just
 	    ;; return the group name.
 	    (lambda (group)
-              (list (list group)))))))
-  (setq group (nnimap-decode-gnus-group group))
+	       (list (list group)))))))
   (when (nnimap-change-group nil server)
     (nnmail-check-syntax)
     (let ((message-id (message-field-value "message-id"))
@@ -1286,7 +1257,6 @@ If LIMIT, first try to limit the search to the N last articles."
     result))
 
 (deffoo nnimap-request-replace-article (article group buffer)
-  (setq group (nnimap-decode-gnus-group group))
   (let (group-art)
     (when (and (nnimap-change-group group)
 	       ;; Put the article into the group.
@@ -1370,8 +1340,7 @@ If LIMIT, first try to limit the search to the N last articles."
 	  (dolist (response responses)
 	    (let* ((sequence (car response))
 		   (response (cadr response))
-		   (group (cadr (assoc sequence sequences)))
-		   (egroup (nnimap-encode-gnus-group group)))
+		   (group (cadr (assoc sequence sequences))))
 	      (when (and group
 			 (equal (caar response) "OK"))
 		(let ((uidnext (nnimap-find-parameter "UIDNEXT" response))
@@ -1383,14 +1352,14 @@ If LIMIT, first try to limit the search to the N last articles."
 		    (setq highest (1- (string-to-number (car uidnext)))))
 		  (cond
 		   ((null highest)
-		    (insert (format "%S 0 1 y\n" egroup)))
+		    (insert (format "%S 0 1 y\n" group)))
 		   ((zerop exists)
 		    ;; Empty group.
-		    (insert (format "%S %d %d y\n" egroup
+		    (insert (format "%S %d %d y\n" group
 				    highest (1+ highest))))
 		   (t
 		    ;; Return the widest possible range.
-		    (insert (format "%S %d 1 y\n" egroup
+		    (insert (format "%S %d 1 y\n" group
 				    (or highest exists)))))))))
 	  t)))))
 
@@ -1402,7 +1371,7 @@ If LIMIT, first try to limit the search to the N last articles."
 		       (nnimap-get-groups)))
 	(unless (assoc group nnimap-current-infos)
 	  ;; Insert dummy numbers here -- they don't matter.
-	  (insert (format "%S 0 1 y\n" (nnimap-encode-gnus-group group)))))
+	  (insert (format "%S 0 1 y\n" group))))
       t)))
 
 (deffoo nnimap-retrieve-group-data-early (server infos)
@@ -1419,8 +1388,7 @@ If LIMIT, first try to limit the search to the N last articles."
 	;; what and how to request the data.
 	(dolist (info infos)
 	  (setq params (gnus-info-params info)
-		group (nnimap-decode-gnus-group
-		       (gnus-group-real-name (gnus-info-group info)))
+		group (gnus-group-real-name (gnus-info-group info))
 		active (cdr (assq 'active params))
 		unexist (assq 'unexist (gnus-info-marks info))
 		uidvalidity (cdr (assq 'uidvalidity params))
@@ -1501,16 +1469,13 @@ If LIMIT, first try to limit the search to the N last articles."
 		     (active (gnus-active group)))
 		(when active
 		  (insert (format "%S %d %d y\n"
-				  (nnimap-encode-gnus-group
-				   (nnimap-decode-gnus-group
-				    (gnus-group-real-name group)))
+				  (gnus-group-real-name group)
 				  (cdr active)
 				  (car active))))))))))))
 
 (defun nnimap-update-infos (flags infos)
   (dolist (info infos)
-    (let* ((group (nnimap-decode-gnus-group
-		   (gnus-group-real-name (gnus-info-group info))))
+    (let* ((group (gnus-group-real-name (gnus-info-group info)))
 	   (marks (cdr (assoc group flags))))
       (when marks
 	(nnimap-update-info info marks)))))
@@ -1723,8 +1688,7 @@ If LIMIT, first try to limit the search to the N last articles."
       (nreverse result))))
 
 (defun nnimap-store-info (info active)
-  (let* ((group (nnimap-decode-gnus-group
-		 (gnus-group-real-name (gnus-info-group info))))
+  (let* ((group (gnus-group-real-name (gnus-info-group info)))
 	 (entry (assoc group nnimap-current-infos)))
     (if entry
 	(setcdr entry (list info active))
@@ -1851,8 +1815,6 @@ If LIMIT, first try to limit the search to the N last articles."
 (autoload 'nnir-search-thread "nnir")
 
 (deffoo nnimap-request-thread (header &optional group server)
-  (when group
-    (setq group (nnimap-decode-gnus-group group)))
   (if gnus-refer-thread-use-nnir
       (nnir-search-thread header)
     (when (nnimap-change-group group server)
diff --git a/lisp/gnus/nnmail.el b/lisp/gnus/nnmail.el
index b6dbbea74cc..e4e8da78d2d 100644
--- a/lisp/gnus/nnmail.el
+++ b/lisp/gnus/nnmail.el
@@ -595,7 +595,7 @@ using different case (i.e. mailing-list@domain vs Mailing-List@Domain)."
 (defun nnmail-request-post (&optional server)
   (mail-send-and-exit nil))
 
-(defvar nnmail-file-coding-system 'raw-text
+(defvar nnmail-file-coding-system 'undecided
   "Coding system used in nnmail.")
 
 (defvar nnmail-incoming-coding-system
@@ -661,9 +661,12 @@ nn*-request-list should have been called before calling this function."
       (condition-case err
 	  (progn
 	    (narrow-to-region (point) (point-at-eol))
-	    (setq group (read buffer))
-	    (unless (stringp group)
-	      (setq group (encode-coding-string (symbol-name group) 'latin-1)))
+	    (setq group (read buffer)
+		  group
+		  (cond ((symbolp group)
+			 (symbol-name group))
+			((numberp group)
+			 (number-to-string group))))
 	    (if (and (numberp (setq max (read buffer)))
 		     (numberp (setq min (read buffer))))
 		(push (list group (cons min max))
@@ -673,7 +676,7 @@ nn*-request-list should have been called before calling this function."
       (forward-line 1))
     group-assoc))
 
-(defcustom nnmail-active-file-coding-system 'raw-text
+(defcustom nnmail-active-file-coding-system 'undecided
   "Coding system for active file."
   :group 'nnmail-various
   :type 'coding-system)
@@ -683,7 +686,7 @@ nn*-request-list should have been called before calling this function."
   (let ((coding-system-for-write nnmail-active-file-coding-system))
     (when file-name
       (with-temp-file file-name
-	(mm-disable-multibyte)
+;	(mm-disable-multibyte)
 	(nnmail-generate-active group-assoc)))))
 
 (defun nnmail-generate-active (alist)
@@ -691,7 +694,7 @@ nn*-request-list should have been called before calling this function."
   (erase-buffer)
   (let (group)
     (while (setq group (pop alist))
-      (insert (format "%S %d %d y\n" (intern (car group)) (cdadr group)
+      (insert (format "%s %d %d y\n" (car group) (cdadr group)
 		      (caadr group))))
     (goto-char (point-max))
     (while (search-backward "\\." nil t)
@@ -1023,7 +1026,7 @@ If SOURCE is a directory spec, try to return the group name component."
       (nnmail-check-duplication message-id func artnum-func))
     1))
 
-(defvar nnmail-group-names-not-encoded-p nil
+(defvar nnmail-group-names-not-encoded-p t
   "Non-nil means group names are not encoded.")
 
 (defun nnmail-split-incoming (incoming func &optional exit-func
@@ -1044,6 +1047,10 @@ will be copied over from that buffer."
       (erase-buffer)
       (if (bufferp incoming)
 	  (insert-buffer-substring incoming)
+	;; The following coding system is set to
+	;; `mm-text-coding-system', which is set to some flavor of
+	;; 'raw-text "to get rid of ^Ms".  But it's going to do a lot
+	;; more than that, right?  Shouldn't this also be 'undecided?
 	(let ((coding-system-for-read nnmail-incoming-coding-system))
 	  (mm-insert-file-contents incoming)))
       (prog1
diff --git a/lisp/gnus/nnmaildir.el b/lisp/gnus/nnmaildir.el
index 9d02773d6f2..86d5148489e 100644
--- a/lisp/gnus/nnmaildir.el
+++ b/lisp/gnus/nnmaildir.el
@@ -419,7 +419,7 @@ This variable is set by `nnmaildir-request-article'.")
 	   (t (signal (car err) (cdr err)))))))))
 
 (defun nnmaildir--update-nov (server group article)
-  (let ((nnheader-file-coding-system 'binary)
+  (let ((nnheader-file-coding-system 'undecided)
 	(srv-dir (nnmaildir--srv-dir server))
 	(storage-version 1) ;; [version article-number msgid [...nov...]]
 	dir gname pgname msgdir prefix suffix file attr mtime novdir novfile
diff --git a/lisp/gnus/nnml.el b/lisp/gnus/nnml.el
index 205e9e48034..453a677eb51 100644
--- a/lisp/gnus/nnml.el
+++ b/lisp/gnus/nnml.el
@@ -740,9 +740,9 @@ article number.  This function is called narrowed to an article."
 
 (defun nnml-active-number (group &optional server)
   "Compute the next article number in GROUP on SERVER."
-  (let* ((encoded (if nnmail-group-names-not-encoded-p
-		      (nnml-encoded-group-name group server)))
-	 (active (cadr (assoc-string (or encoded group) nnml-group-alist))))
+  ;; FIXME: This originally checked `nnml-group-names-not-encoded-p'
+  ;; and maybe encoded the group name.
+  (let ((active (cadr (assoc-string group nnml-group-alist))))
     ;; The group wasn't known to nnml, so we just create an active
     ;; entry for it.
     (unless active
@@ -760,7 +760,7 @@ article number.  This function is called narrowed to an article."
 		(cons (caar nnml-article-file-alist)
 		      (caar (last nnml-article-file-alist)))
 	      (cons 1 0)))
-      (push (list (or encoded group) active) nnml-group-alist))
+      (push (list group active) nnml-group-alist))
     (setcdr active (1+ (cdr active)))
     (while (file-exists-p
 	    (nnml-group-pathname group (int-to-string (cdr active)) server))
@@ -910,7 +910,7 @@ Unless no-active is non-nil, update the active file too."
   ;; Update the active info for this group.
   (let ((group (directory-file-name dir))
 	entry last)
-    (setq group (nnheader-file-to-group (nnml-encoded-group-name group)
+    (setq group (nnheader-file-to-group group
 					nnml-directory)
 	  entry (assoc group nnml-group-alist)
 	  last (or (caadr entry) 0)