; Tramp cleanup

* lisp/net/tramp-adb.el (tramp-adb-maybe-open-connection):
Handle `non-essential'.

* lisp/net/tramp-archive.el: Increase `max-specpdl-size' when
loading tramp-gvfs.

* lisp/net/tramp-rclone.el (tramp-rclone-mounted-p): Reorder for
better traces.
(tramp-rclone-maybe-open-connection): Handle `non-essential'.

* lisp/net/tramp-sh.el (tramp-sh-handle-copy-directory)
(tramp-find-inline-encoding): Simplify check.

* lisp/net/tramp-smb.el (tramp-smb-handle-insert-directory)
(tramp-smb-handle-insert-directory): Simplify check.

* lisp/net/tramp-sudoedit.el (tramp-sudoedit-action-sudo):
Simplify check.
(tramp-sudoedit-maybe-open-connection): Handle `non-essential'.

* lisp/net/tramp.el (tramp-handle-load, tramp-wait-for-regexp):
Simplify check.
(tramp-action-login, tramp-action-password, tramp-action-yesno)
(tramp-action-yn, tramp-action-terminal): Return explicitly t.
(tramp-process-one-action, tramp-process-actions): Adapt docstring.

7 files changed, 83 insertions, 30 deletions

diff --git a/lisp/net/tramp-adb.el b/lisp/net/tramp-adb.el
index 372ce154149..d45695cbecc 100644
--- a/lisp/net/tramp-adb.el
+++ b/lisp/net/tramp-adb.el
@@ -1300,6 +1300,14 @@ connection if a previous connection has died for some reason."
       (tramp-error vec 'file-error "Cannot switch to user `%s'" user))
 
     (unless (process-live-p p)
+      ;; During completion, don't reopen a new connection.  We check
+      ;; this for the process related to `tramp-buffer-name';
+      ;; otherwise `start-file-process' wouldn't run ever when
+      ;; `non-essential' is non-nil.
+      (when (and (tramp-completion-mode-p)
+		 (null (get-process (tramp-buffer-name vec))))
+	(throw 'non-essential 'non-essential))
+
       (save-match-data
 	(when (and p (processp p)) (delete-process p))
 	(if (zerop (length device))
diff --git a/lisp/net/tramp-archive.el b/lisp/net/tramp-archive.el
index e4a7b157a02..f975ccfcfa8 100644
--- a/lisp/net/tramp-archive.el
+++ b/lisp/net/tramp-archive.el
@@ -108,7 +108,10 @@
 ;;; Code:
 
 (eval-when-compile (require 'cl-lib))
-(require 'tramp-gvfs)
+;; Sometimes, compilation fails with "Variable binding depth exceeds
+;; max-specpdl-size".
+(eval-and-compile
+  (let ((max-specpdl-size (* 2 max-specpdl-size))) (require 'tramp-gvfs)))
 
 (autoload 'dired-uncache "dired")
 (autoload 'url-tramp-convert-url-to-tramp "url-tramp")
diff --git a/lisp/net/tramp-rclone.el b/lisp/net/tramp-rclone.el
index bc48d4d3a85..3db8f1d8af7 100644
--- a/lisp/net/tramp-rclone.el
+++ b/lisp/net/tramp-rclone.el
@@ -467,19 +467,19 @@ file names."
   (when (tramp-get-connection-process vec)
     ;; We cannot use `with-connection-property', because we don't want
     ;; to cache a nil result.
-    (or (tramp-get-connection-property
-	 (tramp-get-connection-process vec) "mounted" nil)
+    (unless (tramp-get-connection-property
+	     (tramp-get-connection-process vec) "mounted" nil)
+      (let* ((default-directory temporary-file-directory)
+	     (mount (shell-command-to-string "mount -t fuse.rclone")))
+	(tramp-message vec 6 "%s" "mount -t fuse.rclone")
+	(tramp-message vec 6 "\n%s" mount)
 	(tramp-set-connection-property
 	 (tramp-get-connection-process vec) "mounted"
-	 (let* ((default-directory temporary-file-directory)
-		(mount (shell-command-to-string "mount -t fuse.rclone")))
-	   (tramp-message vec 6 "%s" "mount -t fuse.rclone")
-	   (tramp-message vec 6 "\n%s" mount)
-	   (when (string-match
-		  (format
-		   "^\\(%s:\\S-*\\)" (regexp-quote (tramp-file-name-host vec)))
-		  mount)
-	     (match-string 1 mount)))))))
+	 (when (string-match
+		(format
+		 "^\\(%s:\\S-*\\)" (regexp-quote (tramp-file-name-host vec)))
+		mount)
+	   (match-string 1 mount)))))))
 
 (defun tramp-rclone-flush-directory-cache (vec)
   "Flush directory cache of VEC mount."
@@ -544,6 +544,14 @@ connection if a previous connection has died for some reason."
       (if (zerop (length host))
 	  (tramp-error vec 'file-error "Storage %s not connected" host))
 
+      ;; During completion, don't reopen a new connection.  We check
+      ;; this for the process related to `tramp-buffer-name';
+      ;; otherwise `start-file-process' wouldn't run ever when
+      ;; `non-essential' is non-nil.
+      (when (and (tramp-completion-mode-p)
+		 (null (get-process (tramp-buffer-name vec))))
+	(throw 'non-essential 'non-essential))
+
       ;; We need a process bound to the connection buffer.  Therefore,
       ;; we create a dummy process.  Maybe there is a better solution?
       (unless (get-buffer-process (tramp-get-connection-buffer vec))
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index e4ea9ecb9f6..5ed75132753 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -1931,7 +1931,7 @@ tramp-sh-handle-file-name-all-completions: internal error accessing `%s': `%s'"
 	      (setq newname
 		    (expand-file-name
 		     (file-name-nondirectory dirname) newname)))
-	    (when (not (file-directory-p (file-name-directory newname)))
+	    (unless (file-directory-p (file-name-directory newname))
 		(make-directory (file-name-directory newname) parents))
 	    (tramp-do-copy-or-rename-file-out-of-band
 	     'copy dirname newname keep-date))
@@ -4458,7 +4458,7 @@ Goes through the list `tramp-local-coding-commands' and
 		  ;; actually check the output it gives.  And also, when
 		  ;; redirecting "mimencode" output to /dev/null, then as root
 		  ;; it might change the permissions of /dev/null!
-		  (when (not (stringp rem-enc))
+		  (unless (stringp rem-enc)
 		    (let ((name (symbol-name rem-enc)))
 		      (while (string-match "-" name)
 			(setq name (replace-match "_" nil t name)))
@@ -4471,7 +4471,7 @@ Goes through the list `tramp-local-coding-commands' and
 			   vec (format "%s </dev/null" rem-enc) t)
 		    (throw 'wont-work-remote nil))
 
-		  (when (not (stringp rem-dec))
+		  (unless (stringp rem-dec)
 		    (let ((name (symbol-name rem-dec))
 			  (value (symbol-value rem-dec))
 			  tmpfile)
diff --git a/lisp/net/tramp-smb.el b/lisp/net/tramp-smb.el
index a6c95663dd0..fb9073becd0 100644
--- a/lisp/net/tramp-smb.el
+++ b/lisp/net/tramp-smb.el
@@ -1048,7 +1048,7 @@ PRESERVE-UID-GID and PRESERVE-EXTENDED-ATTRIBUTES are completely ignored."
 	  (when (string-match-p "F" switches)
 	    (mapc
 	     (lambda (x)
-	       (when (not (zerop (length (car x))))
+	       (unless (zerop (length (car x)))
 		 (cond
 		  ((char-equal ?d (string-to-char (nth 1 x)))
 		   (setcar x (concat (car x) "/")))
@@ -1066,7 +1066,7 @@ PRESERVE-UID-GID and PRESERVE-EXTENDED-ATTRIBUTES are completely ignored."
 	  ;; Print entries.
 	  (mapc
 	   (lambda (x)
-	     (when (not (zerop (length (nth 0 x))))
+	     (unless (zerop (length (nth 0 x)))
 	       (let ((attr
 		      (when (tramp-smb-get-stat-capability v)
 			(ignore-errors
diff --git a/lisp/net/tramp-sudoedit.el b/lisp/net/tramp-sudoedit.el
index 6125f6f174b..80c63c16edb 100644
--- a/lisp/net/tramp-sudoedit.el
+++ b/lisp/net/tramp-sudoedit.el
@@ -747,7 +747,7 @@ ID-FORMAT valid values are `string' and `integer'."
   "Check, whether a sudo process has finished.
 Remove unneeded output."
   ;; There might be pending output for the exit status.
-  (when (not (process-live-p proc))
+  (unless (process-live-p proc)
     (while (tramp-accept-process-output proc 0))
     ;; Delete narrowed region, it would be in the way reading a Lisp form.
     (goto-char (point-min))
@@ -768,6 +768,15 @@ connection if a previous connection has died for some reason."
   ;; We need a process bound to the connection buffer.  Therefore, we
   ;; create a dummy process.  Maybe there is a better solution?
   (unless (tramp-get-connection-process vec)
+
+    ;; During completion, don't reopen a new connection.  We check
+    ;; this for the process related to `tramp-buffer-name'; otherwise
+    ;; `start-file-process' wouldn't run ever when `non-essential' is
+    ;; non-nil.
+    (when (and (tramp-completion-mode-p)
+	       (null (get-process (tramp-buffer-name vec))))
+      (throw 'non-essential 'non-essential))
+
     (let ((p (make-network-process
 	      :name (tramp-buffer-name vec)
 	      :buffer (tramp-get-connection-buffer vec)
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index 1f018e5cd49..54a84ca122f 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -3595,10 +3595,9 @@ User is always nil."
 	(tramp-error
 	 v 'file-error
 	 "File `%s' does not include a `.el' or `.elc' suffix" file)))
-    (unless noerror
-      (when (not (file-exists-p file))
-	(tramp-error
-	 v tramp-file-missing "Cannot load nonexistent file `%s'" file)))
+    (unless (or noerror (file-exists-p file))
+      (tramp-error
+       v tramp-file-missing "Cannot load nonexistent file `%s'" file))
     (if (not (file-exists-p file))
 	nil
       (let ((tramp-message-show-message (not nomessage)))
@@ -3902,7 +3901,8 @@ of."
     (with-current-buffer (tramp-get-connection-buffer vec)
       (tramp-message vec 6 "\n%s" (buffer-string)))
     (tramp-message vec 3 "Sending login name `%s'" user)
-    (tramp-send-string vec (concat user tramp-local-end-of-line))))
+    (tramp-send-string vec (concat user tramp-local-end-of-line)))
+  t)
 
 (defun tramp-action-password (proc vec)
   "Query the user for a password."
@@ -3922,7 +3922,8 @@ of."
       (process-send-string
        proc (concat (tramp-read-passwd proc) tramp-local-end-of-line))
       ;; Hide password prompt.
-      (narrow-to-region (point-max) (point-max)))))
+      (narrow-to-region (point-max) (point-max))))
+  t)
 
 (defun tramp-action-succeed (_proc _vec)
   "Signal success in finding shell prompt."
@@ -3945,7 +3946,8 @@ See also `tramp-action-yn'."
 	(throw 'tramp-action 'permission-denied))
       (with-current-buffer (tramp-get-connection-buffer vec)
 	(tramp-message vec 6 "\n%s" (buffer-string)))
-      (tramp-send-string vec (concat "yes" tramp-local-end-of-line)))))
+      (tramp-send-string vec (concat "yes" tramp-local-end-of-line))))
+  t)
 
 (defun tramp-action-yn (proc vec)
   "Ask the user for confirmation using `y-or-n-p'.
@@ -3959,7 +3961,8 @@ See also `tramp-action-yesno'."
 	(throw 'tramp-action 'permission-denied))
       (with-current-buffer (tramp-get-connection-buffer vec)
 	(tramp-message vec 6 "\n%s" (buffer-string)))
-      (tramp-send-string vec (concat "y" tramp-local-end-of-line)))))
+      (tramp-send-string vec (concat "y" tramp-local-end-of-line))))
+  t)
 
 (defun tramp-action-terminal (_proc vec)
   "Tell the remote host which terminal type to use.
@@ -3967,7 +3970,8 @@ The terminal type can be configured with `tramp-terminal-type'."
   (tramp-message vec 5 "Setting `%s' as terminal type." tramp-terminal-type)
   (with-current-buffer (tramp-get-connection-buffer vec)
     (tramp-message vec 6 "\n%s" (buffer-string)))
-  (tramp-send-string vec (concat tramp-terminal-type tramp-local-end-of-line)))
+  (tramp-send-string vec (concat tramp-terminal-type tramp-local-end-of-line))
+  t)
 
 (defun tramp-action-process-alive (proc _vec)
   "Check, whether a process has finished."
@@ -4001,7 +4005,8 @@ The terminal type can be configured with `tramp-terminal-type'."
 ;;; Functions for processing the actions:
 
 (defun tramp-process-one-action (proc vec actions)
-  "Wait for output from the shell and perform one action."
+  "Wait for output from the shell and perform one action.
+See `tramp-process-actions' for the format of ACTIONS."
   (let ((case-fold-search t)
 	found todo item pattern action)
     (while (not found)
@@ -4024,7 +4029,27 @@ The terminal type can be configured with `tramp-terminal-type'."
   "Perform ACTIONS until success or TIMEOUT.
 PROC and VEC indicate the remote connection to be used.  POS, if
 set, is the starting point of the region to be deleted in the
-connection buffer."
+connection buffer.
+
+ACTIONS is a list of (PATTERN ACTION).  The PATTERN should be a
+symbol, a variable.  The value of this variable gives the regular
+expression to search for.  Note that the regexp must match at the
+end of the buffer, \"\\'\" is implicitly appended to it.
+
+The ACTION should also be a symbol, but a function.  When the
+corresponding PATTERN matches, the ACTION function is called.
+
+An ACTION function has two arguments (PROC VEC).  If it returns
+nil, nothing has been done, and the next action shall be called.
+A non-nil return value indicates that the process output has been
+consumed, and new output shall be retrieved, before starting to
+process all ACTIONs, again.  The same happens after calling the
+last ACTION.
+
+If an action determines, that all processing has been done (e.g.,
+because the shell prompt has been detected), it shall throw a
+result.  The symbol `ok' means that all ACTIONs have been
+performed successfully.  Any other value means an error."
   ;; Enable `auth-source', unless "emacs -Q" has been called.  We must
   ;; use the "password-vector" property in case we have several hops.
   (tramp-set-connection-property
@@ -4156,7 +4181,7 @@ nil."
 		  nil proc 'file-error "Process has died"))
 	       (setq found (tramp-check-for-regexp proc regexp)))))
       (tramp-message proc 6 "\n%s" (buffer-string))
-      (when (not found)
+      (unless found
 	(if timeout
 	    (tramp-error
 	     proc 'file-error "[[Regexp `%s' not found in %d secs]]"