Remove Gnus group name encoding/decoding

This completes the process started in c1b63af445. Gnus group names are
now fully decoded inside the Gnus system.

* lisp/gnus/gnus-agent.el (gnus-agent-file-coding-system): Change
  default to utf-8-emacs.
  (gnus-agent-decoded-group-names, gnus-agent-decoded-group-name):
  Remove variable and function. Remove all usage in this file.
* lisp/gnus/gnus-cache.el (gnus-cache-decoded-group-names,
  gnus-cache-unified-group-names, gnus-cache-decoded-group-name):
  Remove these variables and function. Remove all usage in this file.
* lisp/gnus/gnus-group.el (gnus-tmp-decoded-group): Remove this
  variable, gnus-tmp-group is now decoded.
  (gnus-group-completing-read): Don't encode or decode group names
  here.
  (gnus-group-make-group): Remove ENCODED argument.
* lisp/gnus/gnus-srvr.el (gnus-browse-foreign-server): Decode group
  names here.
* lisp/gnus/gnus-start.el (gnus-make-hashtable-from-newsrc-alist):
  check for encoded group names and decode.
  (gnus-active-to-gnus-format): Make sure incoming group names are
  decoded.
  (gnus-read-newsrc-el-file): Check for encoded group names in
  gnus-topic-alist.
* lisp/gnus/nnagent.el: Don't use a unibyte buffer.
* lisp/gnus/nnheader.el (nnheader-file-coding-system): Switch default
  from 'raw-text to 'undecided, on the assumption that 'undecided will
  probably write 'utf-8-emacs unless the user has arranged things
  otherwise.
* lisp/gnus/nnimap.el (nnimap-decode-gnus-group,
  nnimap-encode-gnus-group): Remove functions and their use.
* lisp/gnus/nnmail.el (nnmail-parse-active): Remove encoding.
  (nnmail-active-file-coding-system): Default to 'utf-8-emacs instead
  of 'raw-text.
  (nnmail-group-names-not-encoded-p): Obsolete this variable; stop
  using it.
* lisp/gnus/gnus-art.el:
* lisp/gnus/gnus-cus.el:
* lisp/gnus/gnus-msg.el:
* lisp/gnus/gnus-start.el:
* lisp/gnus/gnus-sum.el:
* lisp/gnus/gnus.el:
* lisp/gnus/nnml.el:
* lisp/gnus/message.el:
* lisp/gnus/nnrss.el: Stop using gnus-group-decoded-name in all these
  files.

19 files changed, 276 insertions, 493 deletions

diff --git a/lisp/gnus/gnus-agent.el b/lisp/gnus/gnus-agent.el
index 40d0d246056..d9c9e940700 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)
@@ -406,8 +406,6 @@ manipulated as follows:
 (defun gnus-agent-read-group ()
   "Read a group name in the minibuffer, with completion."
   (let ((def (or (gnus-group-group-name) gnus-newsgroup-name)))
-    (when def
-      (setq def (gnus-group-decoded-name def)))
     (gnus-group-completing-read nil nil t nil nil def)))
 
 ;;; Fetching setup functions.
@@ -1330,7 +1328,10 @@ 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)
 
@@ -1360,7 +1361,7 @@ 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)
 
@@ -1372,18 +1373,6 @@ downloaded into the agent."
                     oactive-min (read (current-buffer))) ;; min
               (cons oactive-min oactive-max))))))))
 
-(defvar gnus-agent-decoded-group-names nil
-  "Alist of non-ASCII group names and decoded ones.")
-
-(defun gnus-agent-decoded-group-name (group)
-  "Return a decoded group name of GROUP."
-  (or (cdr (assoc group gnus-agent-decoded-group-names))
-      (if (string-match "[^\000-\177]" group)
-          (let ((decoded (gnus-group-decoded-name group)))
-            (push (cons group decoded) gnus-agent-decoded-group-names)
-            decoded)
-        group)))
-
 (defun gnus-agent-group-path (group)
   "Translate GROUP into a file name."
 
@@ -1395,7 +1384,7 @@ downloaded into the agent."
         (nnheader-translate-file-chars
          (nnheader-replace-duplicate-chars-in-string
           (nnheader-replace-chars-in-string
-           (gnus-group-real-name (gnus-agent-decoded-group-name group))
+           (gnus-group-real-name group)
            ?/ ?_)
           ?. ?_)))
   (if (or nnmail-use-long-file-names
@@ -1409,7 +1398,7 @@ downloaded into the agent."
   ;; unplugged.  The agent must, therefore, use the same directory
   ;; while plugged.
   (nnmail-group-pathname
-   (gnus-group-real-name (gnus-agent-decoded-group-name group))
+   (gnus-group-real-name group)
    (if gnus-command-method
        (gnus-agent-directory)
      (let ((gnus-command-method (gnus-find-method-for-group group)))
@@ -1437,7 +1426,7 @@ 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")))
@@ -1525,8 +1514,7 @@ downloaded into the agent."
           (setq selected-sets (nreverse selected-sets))
 
           (gnus-make-directory dir)
-          (gnus-message 7 "Fetching articles for %s..."
-                        (gnus-agent-decoded-group-name group))
+          (gnus-message 7 "Fetching articles for %s..." group)
 
           (unwind-protect
               (while (setq articles (pop selected-sets))
@@ -1537,8 +1525,7 @@ downloaded into the agent."
                     (let (article)
                       (while (setq article (pop articles))
                         (gnus-message 10 "Fetching article %s for %s..."
-                                      article
-                                      (gnus-agent-decoded-group-name group))
+                                      article group)
                         (when (or
                                (gnus-backlog-request-article group article
                                                              nntp-server-buffer)
@@ -1875,8 +1862,7 @@ article numbers will be returned."
       (with-current-buffer nntp-server-buffer
         (if articles
             (progn
-              (gnus-message 8 "Fetching headers for %s..."
-                            (gnus-agent-decoded-group-name group))
+              (gnus-message 8 "Fetching headers for %s..." group)
 
               ;; Fetch them.
               (gnus-make-directory (nnheader-translate-file-chars
@@ -3058,8 +3044,7 @@ FORCE is equivalent to setting the expiration predicates to true."
   ;; provided a non-nil active
 
   (let ((dir (gnus-agent-group-pathname group))
-        (file-name-coding-system nnmail-pathname-coding-system)
-        (decoded (gnus-agent-decoded-group-name group)))
+        (file-name-coding-system nnmail-pathname-coding-system))
     (gnus-agent-with-refreshed-group
      group
      (when (boundp 'gnus-agent-expire-current-dirs)
@@ -3068,8 +3053,8 @@ FORCE is equivalent to setting the expiration predicates to true."
      (if (and (not force)
               (eq 'DISABLE (gnus-agent-find-parameter group
                                                       'agent-enable-expiration)))
-         (gnus-message 5 "Expiry skipping over %s" decoded)
-       (gnus-message 5 "Expiring articles in %s" decoded)
+         (gnus-message 5 "Expiry skipping over %s" group)
+       (gnus-message 5 "Expiring articles in %s" group)
        (gnus-agent-load-alist group)
        (let* ((bytes-freed 0)
               (size-files-deleted 0.0)
@@ -3293,7 +3278,7 @@ line." (point) nov-file)))
                 (keep
                  (gnus-agent-message 10
                                      "gnus-agent-expire: %s:%d: Kept %s article%s."
-                                     decoded article-number keep (if fetch-date " and file" ""))
+                                     group article-number keep (if fetch-date " and file" ""))
                  (when fetch-date
                    (unless (file-exists-p
                             (concat dir (number-to-string
@@ -3301,7 +3286,7 @@ line." (point) nov-file)))
                      (setf (nth 1 entry) nil)
                      (gnus-agent-message 3 "gnus-agent-expire cleared \
 download flag on %s:%d as the cached article file is missing."
-                                         decoded (caar dlist)))
+                                         group (caar dlist)))
                    (unless marker
                      (gnus-message 1 "gnus-agent-expire detected a \
 missing NOV entry.  Run gnus-agent-regenerate-group to restore it.")))
@@ -3379,12 +3364,12 @@ article alist" type) actions))
 
                    (when actions
                      (gnus-agent-message 8 "gnus-agent-expire: %s:%d: %s"
-                                         decoded article-number
+                                         group article-number
                                          (mapconcat #'identity actions ", ")))))
                 (t
                  (gnus-agent-message
                   10 "gnus-agent-expire: %s:%d: Article kept as \
-expiration tests failed." decoded article-number)
+expiration tests failed." group article-number)
                  (gnus-agent-append-to-list
                   tail-alist (cons article-number fetch-date)))
                 )
@@ -3835,7 +3820,7 @@ If REREAD is not nil, downloaded articles are marked as unread."
                     (sit-for 1)
                     t)))))
   (when group
-    (gnus-message 5 "Regenerating in %s" (gnus-agent-decoded-group-name group))
+    (gnus-message 5 "Regenerating in %s" group)
     (let* ((gnus-command-method (or gnus-command-method
                                     (gnus-find-method-for-group group)))
            (file (gnus-agent-article-name ".overview" group))
@@ -3912,8 +3897,7 @@ If REREAD is not nil, downloaded articles are marked as unread."
                           (> (car downloaded) (car nov-arts))))
                  ;; This entry is missing from the overview file
                  (gnus-message 3 "Regenerating NOV %s %d..."
-                               (gnus-agent-decoded-group-name group)
-                               (car downloaded))
+                               group (car downloaded))
                  (let ((file (concat dir (number-to-string (car downloaded)))))
                    (mm-with-unibyte-buffer
                      (nnheader-insert-file-contents file)
diff --git a/lisp/gnus/gnus-art.el b/lisp/gnus/gnus-art.el
index 8f5a313c618..af8ec68ddd2 100644
--- a/lisp/gnus/gnus-art.el
+++ b/lisp/gnus/gnus-art.el
@@ -4506,9 +4506,7 @@ commands:
 (defun gnus-article-setup-buffer ()
   "Initialize the article buffer."
   (let* ((name (if gnus-single-article-buffer "*Article*"
-                 (concat "*Article "
-                         (gnus-group-decoded-name gnus-newsgroup-name)
-                         "*")))
+                 (concat "*Article " gnus-newsgroup-name "*")))
          (original
           (progn (string-match "\\*Article" name)
                  (concat " *Original Article"
diff --git a/lisp/gnus/gnus-cache.el b/lisp/gnus/gnus-cache.el
index afe8a8a416c..f43c4344dc2 100644
--- a/lisp/gnus/gnus-cache.el
+++ b/lisp/gnus/gnus-cache.el
@@ -430,41 +430,7 @@ Returns the list of articles removed."
       (and unread (memq 'unread class))
       (and (not unread) (not ticked) (not dormant) (memq 'read class))))
 
-(defvar gnus-cache-decoded-group-names nil
-  "Alist of original group names and decoded group names.
-Decoding is done according to `gnus-group-name-charset-method-alist'
-or `gnus-group-name-charset-group-alist'.")
-
-(defvar gnus-cache-unified-group-names nil
-  "Alist of unified decoded group names and original group names.
-A group name is decoded according to
-`gnus-group-name-charset-method-alist' or
-`gnus-group-name-charset-group-alist' first, and is encoded and
-decoded again according to `nnmail-pathname-coding-system',
-`file-name-coding-system', or `default-file-name-coding-system'.
-
-It is used when asking for an original group name from a cache
-directory name, in which non-ASCII characters might have been unified
-into the ones of a certain charset particularly if the `utf-8' coding
-system for example was used.")
-
-(defun gnus-cache-decoded-group-name (group)
-  "Return a decoded group name of GROUP."
-  (or (cdr (assoc group gnus-cache-decoded-group-names))
-      (let ((decoded (gnus-group-decoded-name group))
-            (coding (or nnmail-pathname-coding-system
-                        file-name-coding-system
-                        default-file-name-coding-system)))
-        (push (cons group decoded) gnus-cache-decoded-group-names)
-        (push (cons (decode-coding-string
-                     (encode-coding-string decoded coding)
-                     coding)
-                    group)
-              gnus-cache-unified-group-names)
-        decoded)))
-
 (defun gnus-cache-file-name (group article)
-  (setq group (gnus-cache-decoded-group-name group))
   (expand-file-name
    (if (stringp article) article (int-to-string article))
    (file-name-as-directory
@@ -733,12 +699,7 @@ If LOW, update the lower bound instead."
         (push (pop files) alphs)))
     ;; If we have nums, then this is probably a valid group.
     (when (setq nums (sort nums '<))
-      ;; Use non-decoded group name.
-      ;; FIXME: this is kind of a workaround.  The active file should
-      ;; be updated at the time articles are cached.  It will make
-      ;; `gnus-cache-unified-group-names' needless.
-      (puthash (or (cdr (assoc group gnus-cache-unified-group-names))
-                   group)
+      (puthash group
                (cons (car nums) (car (last nums)))
                gnus-cache-active-hashtb))
     ;; Go through all the other files.
diff --git a/lisp/gnus/gnus-cus.el b/lisp/gnus/gnus-cus.el
index fb8b300e350..3598ead7613 100644
--- a/lisp/gnus/gnus-cus.el
+++ b/lisp/gnus/gnus-cus.el
@@ -396,7 +396,7 @@ 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"
@@ -845,8 +845,7 @@ 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 299ebdec50a..7e0ceec17b6 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)
@@ -2117,9 +2103,7 @@ be permanent."
 (defun gnus-group-name-at-point ()
   "Return a group name from around point if it exists, or nil."
   (if (derived-mode-p 'gnus-group-mode)
-      (let ((group (gnus-group-group-name)))
-        (when group
-          (gnus-group-decoded-name group)))
+      (gnus-group-group-name)
     ;; FIXME: Use rx.
     (let ((regexp "[][\C-@-\t\v-*,/:-@\\^`{-\C-?]*\
 \\(nn[a-z]+\\(?:\\+[^][\C-@-*,/:-@\\^`{-\C-?]+\\)?:\
@@ -2160,41 +2144,25 @@ be permanent."
                                              require-match initial-input hist
                                              def)
   "Read a group name with completion.
-Non-ASCII group names are allowed.  The arguments are the same as
-`completing-read' except that COLLECTION and HIST default to
-`gnus-active-hashtb' and `gnus-group-history' respectively if
-they are omitted.  Can handle COLLECTION as a list, hash table,
-or vector."
+The arguments are the same as `completing-read' except that
+COLLECTION and HIST default to `gnus-active-hashtb' and
+`gnus-group-history' respectively if they are omitted.  Can
+handle COLLECTION as a list, hash table, or vector."
+  ;; This function handles vectors for backwards compatibility.  In
+  ;; theory, `collection' will only ever be a list or a hash table.
   (or collection (setq collection gnus-active-hashtb))
   (let* ((choices
-          (mapcar
-           (lambda (g)
-             (if (string-match "[^\000-\177]" g)
-                 (gnus-group-decoded-name g)
-               g))
            (cond ((listp collection)
                   collection)
                  ((vectorp collection)
                   (mapatoms #'symbol-name collection))
                  ((hash-table-p collection)
-                  (hash-table-keys collection)))))
+                  (hash-table-keys collection))))
          (group
           (gnus-completing-read (or prompt "Group") (reverse choices)
                                 require-match initial-input
                                 (or hist 'gnus-group-history)
                                 def)))
-    (unless (cond ((and (listp collection)
-                        (symbolp (car collection)))
-                   (member group (mapcar 'symbol-name collection)))
-                  ((listp collection)
-                   (member group collection))
-                  ((vectorp collection)
-                   (symbol-value (intern-soft group collection)))
-                  ((hash-table-p collection)
-                   (gethash group collection)))
-      (setq group
-            (encode-coding-string
-             group (gnus-group-name-charset nil group))))
     (replace-regexp-in-string "\n" "" group)))
 
 ;;;###autoload
@@ -2755,13 +2723,13 @@ 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."
@@ -2772,10 +2740,6 @@ 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)))
@@ -2784,7 +2748,7 @@ 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))
@@ -2860,20 +2824,19 @@ be removed from the server, even when it's empty."
   (unless (gnus-check-backend-function 'request-delete-group group)
     (error "This back end does not support group deletion"))
   (prog1
-      (let ((group-decoded (gnus-group-decoded-name group)))
-        (when (or no-prompt
-                  (gnus-yes-or-no-p
-                   (format
-                    "Do you really want to delete %s%s? "
-                    group-decoded (if force " and all its contents" ""))))
-          (gnus-message 6 "Deleting group %s..." group-decoded)
-          (if (not (gnus-request-delete-group group force))
-              (gnus-error 3 "Couldn't delete group %s" group-decoded)
-            (gnus-message 6 "Deleting group %s...done" group-decoded)
-            (gnus-group-goto-group group)
-            (gnus-group-kill-group 1 t)
-            (gnus-set-active group nil)
-            t)))
+      (when (or no-prompt
+                (gnus-yes-or-no-p
+                 (format
+                  "Do you really want to delete %s%s? "
+                  group (if force " and all its contents" ""))))
+        (gnus-message 6 "Deleting group %s..." group)
+        (if (not (gnus-request-delete-group group force))
+            (gnus-error 3 "Couldn't delete group %s" group)
+          (gnus-message 6 "Deleting group %s...done" group)
+          (gnus-group-goto-group group)
+          (gnus-group-kill-group 1 t)
+          (gnus-set-active group nil)
+          t))
     (gnus-group-position-point)))
 
 (defun gnus-group-rename-group (group new-name)
@@ -2887,13 +2850,9 @@ and NEW-NAME will be prompted for."
        (error "This back end does not support renaming groups"))
      (setq new-name (gnus-read-group
                      "Rename group to: "
-                     (gnus-group-real-name (gnus-group-decoded-name group)))
+                     (gnus-group-real-name group))
            method (gnus-info-method (gnus-get-info group)))
-     (list group (encode-coding-string
-                  new-name
-                  (gnus-group-name-charset
-                   method
-                   (gnus-group-prefixed-name new-name method))))))
+     (list group (gnus-group-prefixed-name new-name method))))
 
   (unless (gnus-check-backend-function 'request-rename-group group)
     (error "This back end does not support renaming groups"))
@@ -2912,34 +2871,30 @@ and NEW-NAME will be prompted for."
            (gnus-group-real-name new-name)
            (gnus-info-method (gnus-get-info group)))))
 
-  (let ((decoded-group (gnus-group-decoded-name group))
-        (decoded-new-name (gnus-group-decoded-name new-name)))
-    (when (gnus-active new-name)
-      (error "The group %s already exists" decoded-new-name))
+  (when (gnus-active new-name)
+    (error "The group %s already exists" new-name))
 
-    (gnus-message 6 "Renaming group %s to %s..."
-                  decoded-group decoded-new-name)
-    (prog1
-        (if (progn
-              (gnus-group-goto-group group)
-              (not (when (< (gnus-group-group-level) gnus-level-zombie)
-                     (gnus-request-rename-group group new-name))))
-            (gnus-error 3 "Couldn't rename group %s to %s"
-                        decoded-group decoded-new-name)
-          ;; We rename the group internally by killing it...
-          (gnus-group-kill-group)
-          ;; ... changing its name ...
-          (setcar (cdar gnus-list-of-killed-groups) new-name)
-          ;; ... and then yanking it.  Magic!
-          (gnus-group-yank-group)
-          (gnus-set-active new-name (gnus-active group))
-          (gnus-message 6 "Renaming group %s to %s...done"
-                        decoded-group decoded-new-name)
-          new-name)
-      (setq gnus-killed-list (delete group gnus-killed-list))
-      (gnus-set-active group nil)
-      (gnus-dribble-touch)
-      (gnus-group-position-point))))
+  (gnus-message 6 "Renaming group %s to %s..." group new-name)
+  (prog1
+      (if (progn
+            (gnus-group-goto-group group)
+            (not (when (< (gnus-group-group-level) gnus-level-zombie)
+                   (gnus-request-rename-group group new-name))))
+          (gnus-error 3 "Couldn't rename group %s to %s"
+                      group new-name)
+        ;; We rename the group internally by killing it...
+        (gnus-group-kill-group)
+        ;; ... changing its name ...
+        (setcar (cdar gnus-list-of-killed-groups) new-name)
+        ;; ... and then yanking it.  Magic!
+        (gnus-group-yank-group)
+        (gnus-set-active new-name (gnus-active group))
+        (gnus-message 6 "Renaming group %s to %s...done" group new-name)
+        new-name)
+    (setq gnus-killed-list (delete group gnus-killed-list))
+    (gnus-set-active group nil)
+    (gnus-dribble-touch)
+    (gnus-group-position-point)))
 
 (defun gnus-group-edit-group (group &optional part)
   "Edit the group on the current line."
@@ -2966,7 +2921,7 @@ and NEW-NAME will be prompted for."
        ((eq part 'method) "select method")
        ((eq part 'params) "group parameters")
        (t "group info"))
-      (gnus-group-decoded-name group))
+      group)
      `(lambda (form)
         (gnus-group-edit-group-done ',part ,group form)))
     (local-set-key
@@ -3105,8 +3060,7 @@ 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)
@@ -3611,7 +3565,7 @@ up is returned."
                    "Do you really want to mark all articles in %s as read? "
                  "Mark all unread articles in %s as read? ")
                (if (= (length groups) 1)
-                   (gnus-group-decoded-name (car groups))
+                   (car groups)
                  (format "these %d groups" (length groups)))))))
         n
       (while (setq group (pop groups))
@@ -3696,8 +3650,7 @@ Uses the process/prefix convention."
 
 (defun gnus-group-expire-articles-1 (group)
   (when (gnus-check-backend-function 'request-expire-articles group)
-    (gnus-message 6 "Expiring articles in %s..."
-                  (gnus-group-decoded-name group))
+    (gnus-message 6 "Expiring articles in %s..." group)
     (let* ((info (gnus-get-info group))
            (expirable (if (gnus-group-total-expirable-p group)
                           (cons nil (gnus-list-of-read-articles group))
@@ -3724,8 +3677,7 @@ Uses the process/prefix convention."
             ;; Just expire using the normal expiry values.
             (gnus-request-expire-articles articles-to-expire group))))
         (gnus-close-group group))
-      (gnus-message 6 "Expiring articles in %s...done"
-                    (gnus-group-decoded-name group))
+      (gnus-message 6 "Expiring articles in %s...done" group)
       ;; Return the list of un-expired articles.
       (cdr expirable))))
 
@@ -3762,7 +3714,7 @@ Uses the process/prefix convention."
   (dolist (group (gnus-group-process-prefix n))
     (gnus-group-remove-mark group)
     (gnus-message 6 "Changed level of %s from %d to %d"
-                  (gnus-group-decoded-name group)
+                  group
                   (or (gnus-group-group-level) gnus-level-killed)
                   level)
     (gnus-group-change-level
@@ -3909,7 +3861,7 @@ of groups killed."
           ;; `gnus-newsrc-hashtb', this check will always return nil.
           (when (numberp (gnus-group-unread group))
             (gnus-request-update-group-status group 'unsubscribe))
-          (message "Killed group %s" (gnus-group-decoded-name group)))
+          (message "Killed group %s" group))
       ;; If there are lots and lots of groups to be killed, we use
       ;; this thing instead.
       (dolist (group (nreverse groups))
@@ -4047,7 +3999,7 @@ entail asking the server for the groups."
       (add-text-properties
        (point) (prog1 (1+ (point))
                  (insert "       *: "
-                         (gnus-group-decoded-name group)
+                         group
                          "\n"))
        (list 'gnus-group group
              'gnus-unread t
@@ -4494,9 +4446,9 @@ 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
@@ -4685,7 +4637,7 @@ This command may read the active file."
     (while (setq point (text-property-not-all (point) (point-max)
                                               'gnus-group nil))
       (goto-char point)
-      (push (symbol-name (get-text-property point 'gnus-group)) groups)
+      (push (get-text-property point 'gnus-group) groups)
       (forward-char 1))
     groups))
 
@@ -4776,21 +4728,20 @@ Note: currently only implemented in nnml."
     (error "No group to compact"))
   (unless (gnus-check-backend-function 'request-compact-group group)
     (error "This back end does not support group compaction"))
-  (let ((group-decoded (gnus-group-decoded-name group)))
-    (gnus-message 6 "\
+  (gnus-message 6 "\
 Compacting group %s... (this may take a long time)"
-                  group-decoded)
-    (prog1
-        (if (not (gnus-request-compact-group group))
-            (gnus-error 3 "Couldn't compact group %s" group-decoded)
-          (gnus-message 6 "Compacting group %s...done" group-decoded)
-          t)
-      ;; Invalidate the "original article" buffer which might be out of date.
-      ;; #### NOTE: Yes, this might be a bit rude, but since compaction
-      ;; #### will not happen very often, I think this is acceptable.
-      (gnus-kill-buffer gnus-original-article-buffer)
-      ;; Update the group line to reflect new information (art number etc).
-      (gnus-group-update-group-line))))
+                group)
+  (prog1
+      (if (not (gnus-request-compact-group group))
+          (gnus-error 3 "Couldn't compact group %s" group)
+        (gnus-message 6 "Compacting group %s...done" group)
+        t)
+    ;; Invalidate the "original article" buffer which might be out of date.
+    ;; #### NOTE: Yes, this might be a bit rude, but since compaction
+    ;; #### will not happen very often, I think this is acceptable.
+    (gnus-kill-buffer gnus-original-article-buffer)
+    ;; Update the group line to reflect new information (art number etc).
+    (gnus-group-update-group-line)))
 
 (provide 'gnus-group)
 
diff --git a/lisp/gnus/gnus-msg.el b/lisp/gnus/gnus-msg.el
index 819936d935a..25efb8afda3 100644
--- a/lisp/gnus/gnus-msg.el
+++ b/lisp/gnus/gnus-msg.el
@@ -391,7 +391,7 @@ only affect the Gcc copy, but not the original message."
 (defun gnus-inews-make-draft (articles)
   `(lambda ()
      (gnus-inews-make-draft-meta-information
-      ,(gnus-group-decoded-name gnus-newsgroup-name) ',articles)))
+      ,gnus-newsgroup-name ',articles)))
 
 (autoload 'nnir-article-number "nnir" nil nil 'macro)
 (autoload 'nnir-article-group "nnir" nil nil 'macro)
@@ -1680,7 +1680,6 @@ this is a reply."
 (defun gnus-inews-insert-gcc (&optional group)
   "Insert the Gcc to say where the article is to be archived."
   (let* ((group (or group gnus-newsgroup-name))
-         (group (when group (gnus-group-decoded-name group)))
          (var (or gnus-outgoing-message-group gnus-message-archive-group))
          (gcc-self-val
           (and group (not (gnus-virtual-group-p group))
diff --git a/lisp/gnus/gnus-srvr.el b/lisp/gnus/gnus-srvr.el
index 972ff28e63f..71c7807518f 100644
--- a/lisp/gnus/gnus-srvr.el
+++ b/lisp/gnus/gnus-srvr.el
@@ -784,11 +784,13 @@ claim them."
               (while (not (eobp))
                 (ignore-errors
                   (push (cons
-                         (buffer-substring
-                          (point)
-                          (progn
-                            (skip-chars-forward "^ \t")
-                            (point)))
+                         (decode-coding-string
+                          (buffer-substring
+                           (point)
+                           (progn
+                             (skip-chars-forward "^ \t")
+                             (point)))
+                          'utf-8-emacs)
                          (let ((last (read cur)))
                            (cons (read cur) last)))
                         groups))
@@ -796,18 +798,20 @@ claim them."
             (while (not (eobp))
               (ignore-errors
                 (push (cons
-                       (if (eq (char-after) ?\")
-                           (read cur)
-                         (let ((p (point)) (name ""))
-                           (skip-chars-forward "^ \t\\\\")
-                           (setq name (buffer-substring p (point)))
-                           (while (eq (char-after) ?\\)
-                             (setq p (1+ (point)))
-                             (forward-char 2)
-                             (skip-chars-forward "^ \t\\\\")
-                             (setq name (concat name (buffer-substring
-                                                      p (point)))))
-                           name))
+                       (decode-coding-string
+                        (if (eq (char-after) ?\")
+                            (read cur)
+                          (let ((p (point)) (name ""))
+                            (skip-chars-forward "^ \t\\\\")
+                            (setq name (buffer-substring p (point)))
+                            (while (eq (char-after) ?\\)
+                              (setq p (1+ (point)))
+                              (forward-char 2)
+                              (skip-chars-forward "^ \t\\\\")
+                              (setq name (concat name (buffer-substring
+                                                       p (point)))))
+                            name))
+                        'utf-8-emacs)
                        (let ((last (read cur)))
                          (cons (read cur) last)))
                       groups))
@@ -859,12 +863,7 @@ 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 0f91c4d9b4e..f7ede54b105 100644
--- a/lisp/gnus/gnus-start.el
+++ b/lisp/gnus/gnus-start.el
@@ -35,6 +35,7 @@
 (autoload 'gnus-agent-read-servers-validate "gnus-agent")
 (autoload 'gnus-agent-save-local "gnus-agent")
 (autoload 'gnus-agent-possibly-alter-active "gnus-agent")
+(declare-function gnus-group-decoded-name "gnus-group" (string))
 
 (eval-when-compile (require 'cl-lib))
 
@@ -1828,17 +1829,22 @@ 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 "[^[:ascii:]]" (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
@@ -2144,9 +2150,7 @@ 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)))
@@ -2155,7 +2159,11 @@ The info element is shared with the same element of
                              (skip-chars-forward " \t")
                              (memq (char-after)
                                    '(?= ?x ?j)))))
-                (progn (puthash group (cons min max) hashtb)
+                (progn (when (string-match-p "[^[:ascii:]]" group)
+                         ;; NNTP servers may give us encoded group
+                         ;; names.
+                         (setq group (gnus-group-decoded-name group)))
+                       (puthash group (cons min max) hashtb)
                        ;; If group is moderated, stick it in the
                        ;; moderation cache.
                        (when (eq (char-after) ?m)
@@ -2394,6 +2402,17 @@ If FORCE is non-nil, the .newsrc file is read."
         (when gnus-newsrc-assoc
           (setq gnus-newsrc-alist gnus-newsrc-assoc))))
     (gnus-make-hashtable-from-newsrc-alist)
+    (when gnus-topic-alist
+      (setq gnus-topic-alist
+            (mapcar
+             (lambda (elt)
+               (cons (car elt)
+                     (mapcar (lambda (g)
+                               (if (string-match-p "[^[:ascii:]]" g)
+                                   (gnus-group-decoded-name g)
+                                 g))
+                             (cdr elt))))
+             gnus-topic-alist)))
     (when (file-newer-than-file-p file ding-file)
       ;; Old format quick file
       (gnus-message 5 "Reading %s..." file)
@@ -2492,7 +2511,9 @@ If FORCE is non-nil, the .newsrc file is read."
                  (read buf))
             group (if (numberp group)
                       (number-to-string group)
-                    (symbol-name group)))
+                    ;; newsrc files are written as 'raw-text.
+                    (decode-coding-string
+                     (symbol-name group) 'raw-text)))
       (widen)
       (cond
        ;; It's possible that "group" is actually an options line.
@@ -2911,10 +2932,6 @@ 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 73f0eb39184..a6a0bdb2287 100644
--- a/lisp/gnus/gnus-sum.el
+++ b/lisp/gnus/gnus-sum.el
@@ -3500,8 +3500,7 @@ 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.
     (gnus-kill-buffer dead-name)
     (if (get-buffer buffer)
@@ -3984,8 +3983,7 @@ 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
@@ -4016,8 +4014,7 @@ 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,
@@ -5618,25 +5615,24 @@ 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.
@@ -5649,13 +5645,12 @@ 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...
@@ -5663,16 +5658,12 @@ 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))
@@ -5938,13 +5929,11 @@ 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
@@ -5956,8 +5945,7 @@ 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)))
@@ -6199,8 +6187,7 @@ 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))
@@ -7921,11 +7908,11 @@ 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)
@@ -10110,7 +10097,7 @@ 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.
@@ -10132,22 +10119,12 @@ 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))
@@ -10157,7 +10134,7 @@ 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
@@ -12469,27 +12446,23 @@ 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))
@@ -13156,7 +13129,7 @@ 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 9ccdb83865c..c6be59fd19f 100644
--- a/lisp/gnus/gnus-util.el
+++ b/lisp/gnus/gnus-util.el
@@ -1173,16 +1173,9 @@ ARG is passed to the first function."
   "Return non-nil if all ELEMENTS are non-nil."
   (not (memq nil elements)))
 
-;; 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)
       (maphash
        (lambda (group active)
          (when active
diff --git a/lisp/gnus/gnus.el b/lisp/gnus/gnus.el
index 9ee7db9e203..f990569a300 100644
--- a/lisp/gnus/gnus.el
+++ b/lisp/gnus/gnus.el
@@ -3444,11 +3444,9 @@ 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/message.el b/lisp/gnus/message.el
index 4900686b852..71e1750ba4b 100644
--- a/lisp/gnus/message.el
+++ b/lisp/gnus/message.el
@@ -1894,7 +1894,6 @@ You must have the \"hashcash\" binary installed, see `hashcash-path'."
 (autoload 'gnus-delay-article "gnus-delay")
 (autoload 'gnus-extract-address-components "gnus-util")
 (autoload 'gnus-find-method-for-group "gnus")
-(autoload 'gnus-group-decoded-name "gnus-group")
 (autoload 'gnus-group-name-charset "gnus-group")
 (autoload 'gnus-group-name-decode "gnus-group")
 (autoload 'gnus-groups-from-server "gnus")
@@ -5628,7 +5627,7 @@ In posting styles use `(\"Expires\" (make-expires-date 30))'."
           (concat
            msg-id (if msg-id " (")
            (if (car name)
-               (if (string-match "[^\000-\177]" (car name))
+               (if (string-match "[^[:ascii:]]" (car name))
                    ;; Quote a string containing non-ASCII characters.
                    ;; It will make the RFC2047 encoder cause an error
                    ;; if there are special characters.
@@ -7285,12 +7284,11 @@ news, Source is the list of newsgroups is was posted to."
   (let* ((group (message-fetch-field "newsgroups"))
          (from (message-fetch-field "from"))
          (prefix
-          (if group
-              (gnus-group-decoded-name group)
-            (or (and from (or
-                           (car (gnus-extract-address-components from))
-                           (cadr (gnus-extract-address-components from))))
-                "(nowhere)"))))
+          (or group
+              (or (and from (or
+                             (car (gnus-extract-address-components from))
+                             (cadr (gnus-extract-address-components from))))
+                  "(nowhere)"))))
     (concat "["
             (if message-forward-decoded-p
                 prefix
@@ -7304,10 +7302,9 @@ Source is the sender, and if the original message was news, Source is
 the list of newsgroups is was posted to."
   (let* ((group (message-fetch-field "newsgroups"))
          (prefix
-          (if group
-              (gnus-group-decoded-name group)
-            (or (message-fetch-field "from")
-                "(nowhere)"))))
+          (or group
+              (or (message-fetch-field "from")
+                  "(nowhere)"))))
     (concat "["
             (if message-forward-decoded-p
                 prefix
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 6ef324ae916..c87cfc8c7cb 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
@@ -499,7 +498,8 @@ 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 ()
@@ -871,9 +871,6 @@ 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 0c5aaf32d42..6f2ebfb7fe6 100644
--- a/lisp/gnus/nnimap.el
+++ b/lisp/gnus/nnimap.el
@@ -118,12 +118,6 @@ 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
@@ -208,8 +202,6 @@ 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)
@@ -644,8 +636,6 @@ 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)
@@ -677,8 +667,6 @@ 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)
@@ -696,8 +684,6 @@ 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
@@ -847,7 +833,6 @@ 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.
@@ -874,11 +859,10 @@ 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)
@@ -910,23 +894,20 @@ 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)
@@ -941,7 +922,6 @@ 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")))))
@@ -970,9 +950,6 @@ 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
@@ -1006,7 +983,6 @@ textual parts.")
             result))))))
 
 (deffoo nnimap-request-expire-articles (articles group &optional server force)
-  (setq group (nnimap-decode-gnus-group group))
   (cond
    ((null articles)
     nil)
@@ -1151,8 +1127,6 @@ 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)
@@ -1171,7 +1145,6 @@ 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
@@ -1182,7 +1155,6 @@ 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)
@@ -1217,8 +1189,7 @@ 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"))
@@ -1296,7 +1267,6 @@ 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.
@@ -1380,8 +1350,7 @@ 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))
@@ -1393,14 +1362,14 @@ 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)))))
 
@@ -1412,7 +1381,7 @@ 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)
@@ -1429,8 +1398,7 @@ 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))
@@ -1511,16 +1479,13 @@ 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)))))
@@ -1734,8 +1699,7 @@ 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))
@@ -1860,8 +1824,6 @@ 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 0699e818123..de6b01774d6 100644
--- a/lisp/gnus/nnmail.el
+++ b/lisp/gnus/nnmail.el
@@ -665,9 +665,12 @@ 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))
@@ -677,7 +680,7 @@ 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 'utf-8-emacs
   "Coding system for active file."
   :group 'nnmail-various
   :type 'coding-system)
@@ -687,7 +690,7 @@ 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)
@@ -695,7 +698,7 @@ 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)
@@ -1027,8 +1030,8 @@ 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
-  "Non-nil means group names are not encoded.")
+(make-obsolete-variable 'nnmail-group-names-not-encoded-p
+                        "Group names are always decoded" "27.1")
 
 (defun nnmail-split-incoming (incoming func &optional exit-func
                                        group artnum-func junk-func)
@@ -1036,18 +1039,21 @@ If SOURCE is a directory spec, try to return the group name component."
 FUNC will be called with the buffer narrowed to each mail.
 INCOMING can also be a buffer object.  In that case, the mail
 will be copied over from that buffer."
-  (let ( ;; If this is a group-specific split, we bind the split
+  (let (;; If this is a group-specific split, we bind the split
         ;; methods to just this group.
         (nnmail-split-methods (if (and group
                                        (not nnmail-resplit-incoming))
                                   (list (list group ""))
-                                nnmail-split-methods))
-        (nnmail-group-names-not-encoded-p t))
+                                nnmail-split-methods)))
     ;; Insert the incoming file.
     (with-current-buffer (get-buffer-create nnmail-article-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 246f52c8d2b..d62e1e92536 100644
--- a/lisp/gnus/nnmaildir.el
+++ b/lisp/gnus/nnmaildir.el
@@ -415,7 +415,7 @@ 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 89c8b23b65a..302589bd6d7 100644
--- a/lisp/gnus/nnml.el
+++ b/lisp/gnus/nnml.el
@@ -111,36 +111,9 @@ non-nil.")
 
 (nnoo-define-basics nnml)
 
-(eval-when-compile
-  (defsubst nnml-group-name-charset (group server-or-method)
-    (gnus-group-name-charset
-     (if (stringp server-or-method)
-         (gnus-server-to-method
-          (if (string-match "\\+" server-or-method)
-              (concat (substring server-or-method 0 (match-beginning 0))
-                      ":" (substring server-or-method (match-end 0)))
-            (concat "nnml:" server-or-method)))
-       (or server-or-method gnus-command-method '(nnml "")))
-     group)))
-
-(defun nnml-decoded-group-name (group &optional server-or-method)
-  "Return a decoded group name of GROUP on SERVER-OR-METHOD."
-  (if nnmail-group-names-not-encoded-p
-      group
-    (decode-coding-string
-     group
-     (nnml-group-name-charset group server-or-method))))
-
-(defun nnml-encoded-group-name (group &optional server-or-method)
-  "Return an encoded group name of GROUP on SERVER-OR-METHOD."
-  (encode-coding-string
-   group
-   (nnml-group-name-charset group server-or-method)))
-
 (defun nnml-group-pathname (group &optional file server)
   "Return an absolute file name of FILE for GROUP on SERVER."
-  (nnmail-group-pathname (inline (nnml-decoded-group-name group server))
-                         nnml-directory file))
+  (nnmail-group-pathname group nnml-directory file))
 
 (deffoo nnml-retrieve-headers (sequence &optional group server fetch-old)
   (when (nnml-possibly-change-directory group server)
@@ -243,8 +216,7 @@ non-nil.")
             (string-to-number (file-name-nondirectory path)))))))
 
 (deffoo nnml-request-group (group &optional server dont-check info)
-  (let ((file-name-coding-system nnmail-pathname-coding-system)
-        (decoded (nnml-decoded-group-name group server)))
+  (let ((file-name-coding-system nnmail-pathname-coding-system))
     (cond
      ((not (nnml-possibly-change-directory group server))
       (nnheader-report 'nnml "Invalid group (no such directory)"))
@@ -254,15 +226,15 @@ non-nil.")
      ((not (file-directory-p nnml-current-directory))
       (nnheader-report 'nnml "%s is not a directory" nnml-current-directory))
      (dont-check
-      (nnheader-report 'nnml "Group %s selected" decoded)
+      (nnheader-report 'nnml "Group %s selected" group)
       t)
      (t
       (nnheader-re-read-dir nnml-current-directory)
       (nnmail-activate 'nnml)
       (let ((active (nth 1 (assoc-string group nnml-group-alist))))
         (if (not active)
-            (nnheader-report 'nnml "No such group: %s" decoded)
-          (nnheader-report 'nnml "Selected group %s" decoded)
+            (nnheader-report 'nnml "No such group: %s" group)
+          (nnheader-report 'nnml "Selected group %s" group)
           (nnheader-insert "211 %d %d %d %s\n"
                            (max (1+ (- (cdr active) (car active))) 0)
                            (car active) (cdr active) group)))))))
@@ -332,7 +304,6 @@ non-nil.")
          (active-articles
           (nnml-directory-articles nnml-current-directory))
          (is-old t)
-         (decoded (nnml-decoded-group-name group server))
          article rest mod-time number target)
     (nnmail-activate 'nnml)
 
@@ -370,7 +341,7 @@ non-nil.")
             (if target
                 (progn
                   (nnheader-message 5 "Deleting article %s in %s"
-                                    number decoded)
+                                    number group)
                   (condition-case ()
                       (funcall nnmail-delete-file-function article)
                     (file-error
@@ -506,13 +477,12 @@ non-nil.")
                         nnml-current-directory t
                         (concat
                          nnheader-numerical-short-files
-                         "\\|" (regexp-quote nnml-nov-file-name) "$")))
-                      (decoded (nnml-decoded-group-name group server)))
+                         "\\|" (regexp-quote nnml-nov-file-name) "$"))))
                   (dolist (article articles)
                     (when (file-writable-p article)
                       (nnheader-message 5 "Deleting article %s in %s..."
                                         (file-name-nondirectory article)
-                                        decoded)
+                                        group)
                       (funcall nnmail-delete-file-function article))))
                 ;; Try to delete the directory itself.
                 (ignore-errors (delete-directory nnml-current-directory))))
@@ -687,15 +657,7 @@ article number.  This function is called narrowed to an article."
                          (if (stringp nnml-use-compressed-files)
                              nnml-use-compressed-files
                            ".gz")))
-         decoded dec file first headers)
-    (when nnmail-group-names-not-encoded-p
-      (dolist (ga (prog1 group-art (setq group-art nil)))
-        (setq group-art (nconc group-art
-                               (list (cons (nnml-encoded-group-name (car ga)
-                                                                    server)
-                                           (cdr ga))))
-              decoded (nconc decoded (list (car ga)))))
-      (setq dec decoded))
+         file first headers)
     (nnmail-insert-xref group-art)
     (run-hooks 'nnmail-prepare-save-mail-hook)
     (run-hooks 'nnml-prepare-save-mail-hook)
@@ -705,16 +667,10 @@ article number.  This function is called narrowed to an article."
       (forward-line 1))
     ;; We save the article in all the groups it belongs in.
     (dolist (ga group-art)
-      (if nnmail-group-names-not-encoded-p
-          (progn
-            (nnml-possibly-create-directory (car decoded) server)
-            (setq file (nnmail-group-pathname
-                        (pop decoded) nnml-directory
-                        (concat (number-to-string (cdr ga)) extension))))
-        (nnml-possibly-create-directory (car ga) server)
-        (setq file (nnml-group-pathname
-                    (car ga) (concat (number-to-string (cdr ga)) extension)
-                    server)))
+      (nnml-possibly-create-directory (car ga) server)
+      (setq file (nnml-group-pathname
+                  (car ga) (concat (number-to-string (cdr ga)) extension)
+                  server))
       (if first
           ;; It was already saved, so we just make a hard link.
           (let ((file-name-coding-system nnmail-pathname-coding-system))
@@ -731,18 +687,13 @@ article number.  This function is called narrowed to an article."
     (let ((func (if full-nov
                     'nnml-add-nov
                   'nnml-add-incremental-nov)))
-      (if nnmail-group-names-not-encoded-p
-          (dolist (ga group-art)
-            (funcall func (pop dec) (cdr ga) headers))
-        (dolist (ga group-art)
-          (funcall func (car ga) (cdr ga) headers)))))
+      (dolist (ga group-art)
+        (funcall func (car ga) (cdr ga) headers))))
   group-art)
 
 (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))))
+  (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 +711,7 @@ 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))
@@ -821,16 +772,15 @@ article number.  This function is called narrowed to an article."
         headers))))
 
 (defun nnml-get-nov-buffer (group &optional incrementalp)
-  (let* ((decoded (nnml-decoded-group-name group))
-         (buffer (get-buffer-create (format " *nnml %soverview %s*"
+  (let ((buffer (get-buffer-create (format " *nnml %soverview %s*"
                                             (if incrementalp
                                                 "incremental "
                                               "")
-                                            decoded)))
+                                            group)))
          (file-name-coding-system nnmail-pathname-coding-system))
     (with-current-buffer buffer
       (set (make-local-variable 'nnml-nov-buffer-file-name)
-           (nnmail-group-pathname decoded nnml-directory nnml-nov-file-name))
+           (nnmail-group-pathname group nnml-directory nnml-nov-file-name))
       (erase-buffer)
       (when (and (not incrementalp)
                  (file-exists-p nnml-nov-buffer-file-name))
@@ -908,7 +858,7 @@ 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)
diff --git a/lisp/gnus/nnrss.el b/lisp/gnus/nnrss.el
index 82d3f574249..958745d5790 100644
--- a/lisp/gnus/nnrss.el
+++ b/lisp/gnus/nnrss.el
@@ -368,7 +368,7 @@ for decoding when the cdr that the data specify is not available.")
   (with-current-buffer nntp-server-buffer
     (erase-buffer)
     (dolist (group groups)
-      (let ((elem (assoc-string (gnus-group-decoded-name group) nnrss-server-data)))
+      (let ((elem (assoc-string group nnrss-server-data)))
         (insert (format "%S %s 1 y\n" group (or (cadr elem) 0)))))
     'active))