; Sync with Tramp repository

* doc/misc/tramp.texi (Frequently Asked Questions): Mention Emacs 28.

* doc/misc/trampver.texi:
* lisp/net/trampver.el: Change version to "2.4.4-pre".

* lisp/net/tramp-adb.el (tramp-adb-handle-copy-file)
(tramp-adb-handle-rename-file, tramp-adb-handle-process-file):
Use `tramp-file-local-name'.
(tramp-adb-handle-exec-path): Expand `default-directory'.

* lisp/net/tramp-cmds.el (tramp-rename-files):
Use `tramp-file-local-name'.

* lisp/net/tramp-sh.el (tramp-sh-handle-make-symbolic-link)
(tramp-do-copy-or-rename-file-directly)
(tramp-sh-handle-process-file, tramp-set-remote-path)
(tramp-find-inline-encoding, tramp-get-remote-touch):
Use `tramp-file-local-name'.
(tramp-sh-handle-make-process): Support `stderr' as file name.
Delete temporary stderr file.
(tramp-sh-handle-exec-path): Expand `default-directory'.

* lisp/net/tramp-smb.el (tramp-smb-handle-make-symbolic-link)
(tramp-smb-handle-process-file): Use `tramp-file-local-name'.

* lisp/net/tramp-sudoedit.el (tramp-sudoedit-do-copy-or-rename-file)
(tramp-sudoedit-handle-set-file-uid-gid):
Use `tramp-unquote-file-local-name'.
(tramp-sudoedit-handle-make-symbolic-link):
Use `tramp-file-local-name'.
(tramp-sudoedit-handle-file-system-info): Fix a scoping error.

* lisp/net/tramp.el: Bump version to 2.4.4-pre.
(tramp-ignored-file-name-regexp, tramp-time-dont-know)
(tramp-time-doesnt-exist): Fix typo.
(tramp-file-local-name): Extend for non-remote file names.
(tramp-unquote-file-local-name): New defun.
(tramp-completion-make-tramp-file-name): Simplify.
(tramp-set-connection-local-variables-for-buffer)
(tramp-equal-remote, tramp-handle-make-auto-save-file-name):
Use `tramp-tramp-file-p'.
(tramp-handle-file-name-case-insensitive-p)
(tramp-handle-file-truename, tramp-get-remote-tmpdir)
(tramp-make-tramp-temp-file): Use `tramp-file-local-name'.
(tramp-handle-shell-command, tramp-handle-start-file-process):
Implement asynchronous `error-buffer'.

11 files changed, 108 insertions, 78 deletions

diff --git a/doc/misc/tramp.texi b/doc/misc/tramp.texi
index f81d996d73a..049b240b602 100644
--- a/doc/misc/tramp.texi
+++ b/doc/misc/tramp.texi
@@ -3840,8 +3840,8 @@ Where is the latest @value{tramp}?
 @item
 Which systems does it work on?
 
-The package works successfully on Emacs 24, Emacs 25, Emacs 26, and
-Emacs 27.
+The package works successfully on Emacs 24, Emacs 25, Emacs 26, Emacs
+27, and Emacs 28.
 
 While Unix and Unix-like systems are the primary remote targets,
 @value{tramp} has equal success connecting to other platforms, such as
diff --git a/doc/misc/trampver.texi b/doc/misc/trampver.texi
index 478ec7037a8..02a99ebde83 100644
--- a/doc/misc/trampver.texi
+++ b/doc/misc/trampver.texi
@@ -8,7 +8,7 @@
 @c In the Tramp GIT, the version numbers are auto-frobbed from
 @c tramp.el, and the bug report address is auto-frobbed from
 @c configure.ac.
-@set trampver 2.4.3.27.1
+@set trampver 2.4.4-pre
 @set tramp-bug-report-address tramp-devel@@gnu.org
 @set emacsver 24.4
 
diff --git a/lisp/net/tramp-adb.el b/lisp/net/tramp-adb.el
index 5cfcb81708f..1be2d16bcb1 100644
--- a/lisp/net/tramp-adb.el
+++ b/lisp/net/tramp-adb.el
@@ -725,8 +725,8 @@ PRESERVE-UID-GID and PRESERVE-EXTENDED-ATTRIBUTES are completely ignored."
         (with-tramp-progress-reporter
             v 0 (format "Copying %s to %s" filename newname)
           (if (and t1 t2 (tramp-equal-remote filename newname))
-              (let ((l1 (tramp-compat-file-local-name filename))
-                    (l2 (tramp-compat-file-local-name newname)))
+              (let ((l1 (tramp-file-local-name filename))
+                    (l2 (tramp-file-local-name newname)))
                 ;; We must also flush the cache of the directory,
                 ;; because `file-attributes' reads the values from
                 ;; there.
@@ -809,8 +809,8 @@ PRESERVE-UID-GID and PRESERVE-EXTENDED-ATTRIBUTES are completely ignored."
           (if (and t1 t2
                    (tramp-equal-remote filename newname)
                    (not (file-directory-p filename)))
-              (let ((l1 (tramp-compat-file-local-name filename))
-                    (l2 (tramp-compat-file-local-name newname)))
+              (let ((l1 (tramp-file-local-name filename))
+                    (l2 (tramp-file-local-name newname)))
                 ;; We must also flush the cache of the directory, because
                 ;; `file-attributes' reads the values from there.
                 (tramp-flush-file-properties v l1)
@@ -846,7 +846,7 @@ PRESERVE-UID-GID and PRESERVE-EXTENDED-ATTRIBUTES are completely ignored."
         (setq infile (expand-file-name infile))
         (if (tramp-equal-remote default-directory infile)
             ;; INFILE is on the same remote host.
-            (setq input (with-parsed-tramp-file-name infile nil localname))
+            (setq input (tramp-file-local-name infile))
           ;; INFILE must be copied to remote host.
           (setq input (tramp-make-tramp-temp-file v)
                 tmpinput (tramp-make-tramp-file-name v input))
@@ -877,8 +877,7 @@ PRESERVE-UID-GID and PRESERVE-EXTENDED-ATTRIBUTES are completely ignored."
           (setcar (cdr destination) (expand-file-name (cadr destination)))
           (if (tramp-equal-remote default-directory (cadr destination))
               ;; stderr is on the same remote host.
-              (setq stderr (with-parsed-tramp-file-name
-                               (cadr destination) nil localname))
+              (setq stderr (tramp-file-local-name (cadr destination)))
             ;; stderr must be copied to remote host.  The temporary
             ;; file must be deleted after execution.
             (setq stderr (tramp-make-tramp-temp-file v)
@@ -1062,7 +1061,7 @@ PRESERVE-UID-GID and PRESERVE-EXTENDED-ATTRIBUTES are completely ignored."
           (read (current-buffer)))
         ":" 'omit)))
    ;; The equivalent to `exec-directory'.
-   `(,(tramp-compat-file-local-name default-directory))))
+   `(,(tramp-file-local-name (expand-file-name default-directory)))))
 
 (defun tramp-adb-get-device (vec)
   "Return full host name from VEC to be used in shell execution.
diff --git a/lisp/net/tramp-cmds.el b/lisp/net/tramp-cmds.el
index 9d1025b9072..b4dca2321c1 100644
--- a/lisp/net/tramp-cmds.el
+++ b/lisp/net/tramp-cmds.el
@@ -358,7 +358,7 @@ The remote connection identified by SOURCE is flushed by
 
   ;; Append local file name if none is specified.
   (when (string-equal (file-remote-p target) target)
-    (setq target (concat target (file-remote-p source 'localname))))
+    (setq target (concat target (tramp-file-local-name source))))
   ;; Make them directory names.
   (setq source (directory-file-name source)
         target (directory-file-name target))
diff --git a/lisp/net/tramp-compat.el b/lisp/net/tramp-compat.el
index 723b8cfa1e3..3f25afedb99 100644
--- a/lisp/net/tramp-compat.el
+++ b/lisp/net/tramp-compat.el
@@ -41,6 +41,7 @@
 (require 'shell)
 (require 'subr-x)
 
+;; `temporary-file-directory' as function is introduced with Emacs 26.1.
 (declare-function tramp-handle-temporary-file-directory "tramp")
 
 ;; For not existing functions, obsolete functions, or functions with a
diff --git a/lisp/net/tramp-rclone.el b/lisp/net/tramp-rclone.el
index 9f539850139..0d1ef0f0e91 100644
--- a/lisp/net/tramp-rclone.el
+++ b/lisp/net/tramp-rclone.el
@@ -564,7 +564,7 @@ connection if a previous connection has died for some reason."
                  ,(tramp-rclone-mount-point vec)
                  ;; This could be nil.
                  ,(tramp-get-method-parameter vec 'tramp-mount-args))))
-        (while (not (file-exists-p (tramp-make-tramp-file-name vec 'localname)))
+        (while (not (file-exists-p (tramp-make-tramp-file-name vec 'noloc)))
           (tramp-cleanup-connection vec 'keep-debug 'keep-password))
 
         ;; Mark it as connected.
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index af97328b3d3..6a83cfebfa8 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -1051,9 +1051,7 @@ component is used as the target of the symlink."
       (let ((non-essential t))
         (when (and (tramp-tramp-file-p target)
                    (tramp-file-name-equal-p v (tramp-dissect-file-name target)))
-          (setq target
-                (tramp-file-name-localname
-                 (tramp-dissect-file-name (expand-file-name target))))))
+          (setq target (tramp-file-local-name (expand-file-name target)))))
 
       ;; If TARGET is still remote, quote it.
       (if (tramp-tramp-file-p target)
@@ -2171,8 +2169,8 @@ the uid and gid from FILENAME."
                             v 'file-error
                             "Unknown operation `%s', must be `copy' or `rename'"
                             op))))
-             (localname1 (tramp-compat-file-local-name filename))
-             (localname2 (tramp-compat-file-local-name newname))
+             (localname1 (tramp-file-local-name filename))
+             (localname2 (tramp-file-local-name newname))
              (prefix (file-remote-p (if t1 filename newname)))
              cmd-result)
         (when (and (eq op 'copy) (file-directory-p filename))
@@ -2797,7 +2795,8 @@ the result will be a local, non-Tramp, file name."
 ;; this, its original contents must be saved, and restored once
 ;; connection has been setup.
 (defun tramp-sh-handle-make-process (&rest args)
-  "Like `make-process' for Tramp files."
+  "Like `make-process' for Tramp files.
+STDERR can also be a file name."
   (when args
     (with-parsed-tramp-file-name (expand-file-name default-directory) nil
       (let ((name (plist-get args :name))
@@ -2829,14 +2828,21 @@ the result will be a local, non-Tramp, file name."
           (signal 'wrong-type-argument (list #'functionp sentinel)))
         (unless (or (null stderr) (bufferp stderr) (stringp stderr))
           (signal 'wrong-type-argument (list #'stringp stderr)))
+        (when (and (stringp stderr) (tramp-tramp-file-p stderr)
+                   (not (tramp-equal-remote default-directory stderr)))
+          (signal 'file-error (list "Wrong stderr" stderr)))
 
         (let* ((buffer
                 (if buffer
                     (get-buffer-create buffer)
                   ;; BUFFER can be nil.  We use a temporary buffer.
                   (generate-new-buffer tramp-temp-buffer-name)))
-               (stderr (and stderr (get-buffer-create stderr)))
-               (tmpstderr (and stderr (tramp-make-tramp-temp-file v)))
+               ;; STDERR can also be a file name.
+               (tmpstderr
+                (and stderr
+                     (if (and (stringp stderr) (tramp-tramp-file-p stderr))
+                         (tramp-unquote-file-local-name stderr)
+                       (tramp-make-tramp-temp-file v))))
                (program (car command))
                (args (cdr command))
                ;; When PROGRAM matches "*sh", and the first arg is
@@ -2965,13 +2971,20 @@ the result will be a local, non-Tramp, file name."
                       (ignore-errors
                         (set-process-query-on-exit-flag p (null noquery))
                         (set-marker (process-mark p) (point)))
+                      ;; Copy tmpstderr file.
+                      (when (and (stringp stderr)
+                                 (not (tramp-tramp-file-p stderr)))
+                        (add-function
+                         :after (process-sentinel p)
+                         (lambda (_proc _msg)
+                           (rename-file
+                            (tramp-make-tramp-file-name v tmpstderr) stderr))))
                       ;; Provide error buffer.  This shows only
                       ;; initial error messages; messages arriving
                       ;; later on shall be inserted by `auto-revert'.
-                      ;; The temporary file will still be existing.
-                      ;; TODO: Write a sentinel, which deletes the
-                      ;; temporary file.
-                      (when tmpstderr
+                      ;; The temporary file will exist until the
+                      ;; process is deleted.
+                      (when (bufferp stderr)
                         ;; We must flush them here already; otherwise
                         ;; `insert-file-contents' will fail.
                         (tramp-flush-connection-property v "process-name")
@@ -2979,7 +2992,13 @@ the result will be a local, non-Tramp, file name."
                         (with-current-buffer stderr
                           (insert-file-contents
                            (tramp-make-tramp-file-name v tmpstderr) 'visit)
-                          (auto-revert-mode)))
+                          (auto-revert-mode))
+                        ;; Delete tmpstderr file.
+                        (add-function
+                         :after (process-sentinel p)
+                         (lambda (_proc _msg)
+                           (delete-file
+                            (tramp-make-tramp-file-name v tmpstderr)))))
                       ;; Return process.
                       p)))
 
@@ -3028,7 +3047,7 @@ the result will be a local, non-Tramp, file name."
         (setq infile (expand-file-name infile))
         (if (tramp-equal-remote default-directory infile)
             ;; INFILE is on the same remote host.
-            (setq input (with-parsed-tramp-file-name infile nil localname))
+            (setq input (tramp-file-local-name infile))
           ;; INFILE must be copied to remote host.
           (setq input (tramp-make-tramp-temp-file v)
                 tmpinput (tramp-make-tramp-file-name v input 'nohop))
@@ -3059,8 +3078,7 @@ the result will be a local, non-Tramp, file name."
           (setcar (cdr destination) (expand-file-name (cadr destination)))
           (if (tramp-equal-remote default-directory (cadr destination))
               ;; stderr is on the same remote host.
-              (setq stderr (with-parsed-tramp-file-name
-                               (cadr destination) nil localname))
+              (setq stderr (tramp-file-local-name (cadr destination)))
             ;; stderr must be copied to remote host.  The temporary
             ;; file must be deleted after execution.
             (setq stderr (tramp-make-tramp-temp-file v)
@@ -3122,7 +3140,7 @@ the result will be a local, non-Tramp, file name."
   (append
    (tramp-get-remote-path (tramp-dissect-file-name default-directory))
    ;; The equivalent to `exec-directory'.
-   `(,(tramp-compat-file-local-name default-directory))))
+   `(,(tramp-file-local-name (expand-file-name default-directory)))))
 
 (defun tramp-sh-handle-file-local-copy (filename)
   "Like `file-local-copy' for Tramp files."
@@ -3995,8 +4013,7 @@ variable PATH."
       (setq tmpfile
             (tramp-make-tramp-file-name vec (tramp-make-tramp-temp-file vec)))
       (write-region command nil tmpfile)
-      (tramp-send-command
-       vec (format ". %s" (tramp-compat-file-local-name tmpfile)))
+      (tramp-send-command vec (format ". %s" (tramp-file-local-name tmpfile)))
       (delete-file tmpfile))))
 
 ;; ------------------------------------------------------------
@@ -4513,7 +4530,7 @@ Goes through the list `tramp-local-coding-commands' and
                               (format-spec
                                value
                                (format-spec-make
-                                ?t (tramp-compat-file-local-name tmpfile)))))
+                                ?t (tramp-file-local-name tmpfile)))))
                       (tramp-maybe-send-script vec value name)
                       (setq rem-dec name)))
                   (tramp-message
@@ -4796,7 +4813,7 @@ If there is just some editing, retry it after 5 seconds."
          vec 5 "Cannot timeout session, trying it again in %s seconds." 5)
         (run-at-time 5 nil 'tramp-timeout-session vec))
     (tramp-message
-     vec 3 "Timeout session %s" (tramp-make-tramp-file-name vec 'localname))
+     vec 3 "Timeout session %s" (tramp-make-tramp-file-name vec 'noloc))
     (tramp-cleanup-connection vec 'keep-debug)))
 
 (defun tramp-maybe-open-connection (vec)
@@ -5594,7 +5611,7 @@ This command is returned only if `delete-by-moving-to-trash' is non-nil."
            "%s -t %s %s"
            result
            (format-time-string "%Y%m%d%H%M.%S")
-           (tramp-compat-file-local-name tmpfile))))
+           (tramp-file-local-name tmpfile))))
         (delete-file tmpfile))
       result)))
 
diff --git a/lisp/net/tramp-smb.el b/lisp/net/tramp-smb.el
index bf77ab9dee8..d233af124e8 100644
--- a/lisp/net/tramp-smb.el
+++ b/lisp/net/tramp-smb.el
@@ -1188,9 +1188,7 @@ component is used as the target of the symlink."
       (let ((non-essential t))
         (when (and (tramp-tramp-file-p target)
                    (tramp-file-name-equal-p v (tramp-dissect-file-name target)))
-          (setq target
-                (tramp-file-name-localname
-                 (tramp-dissect-file-name (expand-file-name target))))))
+          (setq target (tramp-file-local-name (expand-file-name target)))))
 
       ;; If TARGET is still remote, quote it.
       (if (tramp-tramp-file-p target)
@@ -1244,7 +1242,7 @@ component is used as the target of the symlink."
         (setq infile (expand-file-name infile))
         (if (tramp-equal-remote default-directory infile)
             ;; INFILE is on the same remote host.
-            (setq input (with-parsed-tramp-file-name infile nil localname))
+            (setq input (tramp-file-local-name infile))
           ;; INFILE must be copied to remote host.
           (setq input (tramp-make-tramp-temp-file v)
                 tmpinput (tramp-make-tramp-file-name v input))
diff --git a/lisp/net/tramp-sudoedit.el b/lisp/net/tramp-sudoedit.el
index 08188cefde3..e5590b8cf6c 100644
--- a/lisp/net/tramp-sudoedit.el
+++ b/lisp/net/tramp-sudoedit.el
@@ -265,10 +265,8 @@ absolute file names."
               v 0 (format "%s %s to %s" msg-operation filename newname)
             (unless (tramp-sudoedit-send-command
                      v sudoedit-operation
-                     (tramp-compat-file-name-unquote
-                      (tramp-compat-file-local-name filename))
-                     (tramp-compat-file-name-unquote
-                      (tramp-compat-file-local-name newname)))
+                     (tramp-unquote-file-local-name filename)
+                     (tramp-unquote-file-local-name newname))
               (tramp-error
                v 'file-error
                "Error %s `%s' `%s'" msg-operation filename newname))))
@@ -615,9 +613,7 @@ component is used as the target of the symlink."
       (let ((non-essential t))
         (when (and (tramp-tramp-file-p target)
                    (tramp-file-name-equal-p v (tramp-dissect-file-name target)))
-          (setq target
-                (tramp-file-name-localname
-                 (tramp-dissect-file-name (expand-file-name target))))))
+          (setq target (tramp-file-local-name (expand-file-name target)))))
 
       ;; If TARGET is still remote, quote it.
       (if (tramp-tramp-file-p target)
@@ -715,8 +711,7 @@ ID-FORMAT valid values are `string' and `integer'."
        (format "%d:%d"
                (or uid (tramp-sudoedit-get-remote-uid v 'integer))
                (or gid (tramp-sudoedit-get-remote-gid v 'integer)))
-       (tramp-compat-file-name-unquote
-        (tramp-compat-file-local-name filename)))))
+       (tramp-unquote-file-local-name filename))))
 
 (defun tramp-sudoedit-handle-write-region
   (start end filename &optional append visit lockname mustbenew)
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index 52c6a9ec430..22bac9ce459 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -7,7 +7,7 @@
 ;; Maintainer: Michael Albinus <michael.albinus@gmx.de>
 ;; Keywords: comm, processes
 ;; Package: tramp
-;; Version: 2.4.3
+;; Version: 2.4.4-pre
 ;; Package-Requires: ((emacs "24.4"))
 ;; Package-Type: multi
 ;; URL: https://savannah.gnu.org/projects/tramp
@@ -1340,13 +1340,20 @@ entry does not exist, return nil."
 This function removes from NAME the specification of the remote
 host and the method of accessing the host, leaving only the part
 that identifies NAME locally on the remote system.  NAME must be
-a string that matches `tramp-file-name-regexp'.  The returned
-file name can be used directly as argument of `process-file',
-`start-file-process', or `shell-command'."
+a string that matches `tramp-file-name-regexp'.  If NAME does not
+match `tramp-file-name-regexp', just NAME is returned.  The
+returned file name can be used directly as argument of
+`process-file', `start-file-process', or `shell-command'."
   (save-match-data
-    (and (tramp-tramp-file-p name)
-         (string-match (nth 0 tramp-file-name-structure) name)
-         (match-string (nth 4 tramp-file-name-structure) name))))
+    (or (and (tramp-tramp-file-p name)
+             (string-match (nth 0 tramp-file-name-structure) name)
+             (match-string (nth 4 tramp-file-name-structure) name))
+        name)))
+
+;; The localname can be quoted with "/:".  Extract this.
+(defun tramp-unquote-file-local-name (name)
+  "Return unquoted localname of NAME."
+  (tramp-compat-file-name-unquote (tramp-file-local-name name)))
 
 (defun tramp-find-method (method user host)
   "Return the right method string to use depending on USER and HOST.
@@ -1593,7 +1600,7 @@ necessary only.  This function will be used in file name completion."
                   tramp-prefix-ipv6-format host tramp-postfix-ipv6-format)
                host)
              tramp-postfix-host-format))
-          (when localname localname)))
+          localname))
 
 (defun tramp-get-buffer (vec &optional dont-create)
   "Get the connection buffer to be used for VEC.
@@ -1649,7 +1656,7 @@ version, the function does nothing."
   "Set connection-local variables in the current buffer.
 If connection-local variables are not supported by this Emacs
 version, the function does nothing."
-  (when (file-remote-p default-directory)
+  (when (tramp-tramp-file-p default-directory)
     ;; `hack-connection-local-variables-apply' exists since Emacs 26.1.
     (tramp-compat-funcall
      'hack-connection-local-variables-apply
@@ -3248,7 +3255,7 @@ User is always nil."
                   ;; lower case letters.  This avoids us to create a
                   ;; temporary file.
                   (while (and (string-match-p
-                               "[a-z]" (tramp-compat-file-local-name candidate))
+                               "[a-z]" (tramp-file-local-name candidate))
                               (not (file-exists-p candidate)))
                     (setq candidate
                           (directory-file-name
@@ -3258,8 +3265,7 @@ User is always nil."
                   ;; to Emacs 26+ like `file-name-case-insensitive-p',
                   ;; so there is no compatibility problem calling it.
                   (unless
-                      (string-match-p
-                       "[a-z]" (tramp-compat-file-local-name candidate))
+                      (string-match-p "[a-z]" (tramp-file-local-name candidate))
                     (setq tmpfile
                           (let ((default-directory
                                   (file-name-directory filename)))
@@ -3272,7 +3278,7 @@ User is always nil."
                       (file-exists-p
                        (concat
                         (file-remote-p candidate)
-                        (upcase (tramp-compat-file-local-name candidate))))
+                        (upcase (tramp-file-local-name candidate))))
                     ;; Cleanup.
                     (when tmpfile (delete-file tmpfile)))))))))))
 
@@ -3414,7 +3420,7 @@ User is always nil."
                (tramp-error
                 v1 'file-error
                 "Maximum number (%d) of symlinks exceeded" numchase-limit)))
-           (tramp-compat-file-local-name (directory-file-name result)))))))))
+           (tramp-file-local-name (directory-file-name result)))))))))
 
 (defun tramp-handle-file-writable-p (filename)
   "Like `file-writable-p' for Tramp files."
@@ -3699,7 +3705,7 @@ support symbolic links."
           (rename-uniquely))
         (setq output-buffer (get-buffer-create bname)))))
 
-    (setq buffer (if (and (not asynchronous) error-buffer)
+    (setq buffer (if error-buffer
                      (with-parsed-tramp-file-name default-directory nil
                        (list output-buffer
                              (tramp-make-tramp-file-name
@@ -3727,13 +3733,24 @@ support symbolic links."
               ;; Run the process.
               (setq p (start-file-process-shell-command
                        (buffer-name output-buffer) buffer command))
-            ;; Display output.
-            (with-current-buffer output-buffer
-              (display-buffer output-buffer '(nil (allow-no-window . t)))
-              (setq mode-line-process '(":%s"))
-              (shell-mode)
-              (set-process-sentinel p #'shell-command-sentinel)
-              (set-process-filter p #'comint-output-filter))))
+            (if (process-live-p p)
+                ;; Display output.
+                (with-current-buffer output-buffer
+                  (display-buffer output-buffer '(nil (allow-no-window . t)))
+                  (setq mode-line-process '(":%s"))
+                  (shell-mode)
+                  (set-process-filter p #'comint-output-filter)
+                  (set-process-sentinel
+                   p (if (listp buffer)
+                         (lambda (_proc _string)
+                           (with-current-buffer error-buffer
+                             (insert-file-contents (cadr buffer)))
+                           (delete-file (cadr buffer)))
+                       #'shell-command-sentinel)))
+              ;; Show stderr.
+              (with-current-buffer error-buffer
+                (insert-file-contents (cadr buffer)))
+              (delete-file (cadr buffer)))))
 
       (prog1
           ;; Run the process.
@@ -3756,13 +3773,16 @@ support symbolic links."
             (display-message-or-buffer output-buffer)))))))
 
 (defun tramp-handle-start-file-process (name buffer program &rest args)
-  "Like `start-file-process' for Tramp files."
+  "Like `start-file-process' for Tramp files.
+BUFFER might be a list, in this case STDERR is separated."
   ;; `make-process' knows the `:file-handler' argument since Emacs 27.1 only.
   (tramp-file-name-handler
    'make-process
    :name name
-   :buffer buffer
+   :buffer (if (listp buffer) (car buffer) buffer)
    :command (and program (cons program args))
+   ;; `shell-command' adds an errfile to `buffer'.
+   :stderr (when (listp buffer) (cadr buffer))
    :noquery nil
    :file-handler t))
 
@@ -4363,7 +4383,7 @@ would yield t.  On the other hand, the following check results in nil:
   (tramp-equal-remote \"/sudo::/etc\" \"/su::/etc\")
 
 If both files are local, the function returns t."
-  (or (and (null (file-remote-p file1)) (null (file-remote-p file2)))
+  (or (and (null (tramp-tramp-file-p file1)) (null (tramp-tramp-file-p file2)))
       (and (tramp-tramp-file-p file1) (tramp-tramp-file-p file2)
            (string-equal (file-remote-p file1) (file-remote-p file2)))))
 
@@ -4633,7 +4653,7 @@ This handles also chrooted environments, which are not regarded as local."
            (tramp-make-tramp-file-name
             vec (or (tramp-get-method-parameter vec 'tramp-tmpdir) "/tmp"))))
       (or (and (file-directory-p dir) (file-writable-p dir)
-               (tramp-compat-file-local-name dir))
+               (tramp-file-local-name dir))
           (tramp-error vec 'file-error "Directory %s not accessible" dir))
       dir)))
 
@@ -4656,7 +4676,7 @@ Return the local name of the temporary file."
         (set-file-modes result #o0700)))
 
     ;; Return the local part.
-    (with-parsed-tramp-file-name result nil localname)))
+    (tramp-file-local-name result)))
 
 (defun tramp-delete-temp-file-function ()
   "Remove temporary files related to current buffer."
@@ -4683,7 +4703,7 @@ this file, if that variable is non-nil."
 
   (let ((system-type
          (if (and (stringp tramp-auto-save-directory)
-                  (file-remote-p tramp-auto-save-directory))
+                  (tramp-tramp-file-p tramp-auto-save-directory))
              'not-windows
            system-type))
         (auto-save-file-name-transforms
diff --git a/lisp/net/trampver.el b/lisp/net/trampver.el
index dacdd44102f..b31f0e0fd26 100644
--- a/lisp/net/trampver.el
+++ b/lisp/net/trampver.el
@@ -39,7 +39,7 @@
 (defvar inhibit-message)
 
 ;;;###tramp-autoload
-(defconst tramp-version "2.4.3.27.1"
+(defconst tramp-version "2.4.4-pre"
   "This version of Tramp.")
 
 ;;;###tramp-autoload
@@ -73,7 +73,7 @@
 ;; Check for Emacs version.
 (let ((x   (if (not (string-lessp emacs-version "24.4"))
       "ok"
-    (format "Tramp 2.4.3.27.1 is not fit for %s"
+    (format "Tramp 2.4.4-pre is not fit for %s"
             (replace-regexp-in-string "\n" "" (emacs-version))))))
   (unless (string-equal "ok" x) (error "%s" x)))