* minibuffer.el (read-file-name-default): Bind `non-essential' to `t'.

* net/tramp.el (tramp-file-name-handler): Catch 'non-essential.

* net/ange-ftp.el (ange-ftp-gwp-start, ange-ftp-start-process):
* net/tramp-sh.el (tramp-maybe-open-connection):
Throw if `non-essential' is non-nil.

5 files changed, 46 insertions, 12 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 560f1212b71..fbcff3e97c0 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,13 @@
+2012-06-17  Michael Albinus  <michael.albinus@gmx.de>
+
+        * minibuffer.el (read-file-name-default): Bind `non-essential' to `t'.
+
+        * net/tramp.el (tramp-file-name-handler): Catch 'non-essential.
+
+        * net/ange-ftp.el (ange-ftp-gwp-start, ange-ftp-start-process):
+        * net/tramp-sh.el (tramp-maybe-open-connection):
+        Throw if `non-essential' is non-nil.
+
 2012-06-17  Martin Rudalics  <rudalics@gmx.at>
 
         * window.el (special-display-p): Signal an error if BUFFER-NAME
diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index 6cd7af7fd01..e4453afe046 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -2335,7 +2335,8 @@ See `read-file-name' for the meaning of the arguments."
             (if (consp default-filename)
                 (mapcar 'abbreviate-file-name default-filename)
               (abbreviate-file-name default-filename))))
-  (let ((insdef (cond
+  (let ((non-essential t)
+        (insdef (cond
                  ((and insert-default-directory (stringp dir))
                   (if initial
                       (cons (minibuffer--double-dollars (concat dir initial))
diff --git a/lisp/net/ange-ftp.el b/lisp/net/ange-ftp.el
index 447549f58cd..4ca40fdabef 100644
--- a/lisp/net/ange-ftp.el
+++ b/lisp/net/ange-ftp.el
@@ -1774,6 +1774,10 @@ good, skip, fatal, or unknown."
 
 (defun ange-ftp-gwp-start (host user name args)
   "Login to the gateway machine and fire up an FTP process."
+  ;; If `non-essential' is non-nil, don't reopen a new connection.  It
+  ;; will be catched in Tramp.
+  (when non-essential
+    (throw 'non-essential 'non-essential))
   (let (;; It would be nice to make process-connection-type nil,
         ;; but that doesn't work: ftp never responds.
         ;; Can anyone find a fix for that?
@@ -1905,6 +1909,10 @@ been queued with no result.  CONT will still be called, however."
   "Spawn a new FTP process ready to connect to machine HOST and give it NAME.
 If HOST is only FTP-able through a gateway machine then spawn a shell
 on the gateway machine to do the FTP instead."
+  ;; If `non-essential' is non-nil, don't reopen a new connection.  It
+  ;; will be catched in Tramp.
+  (when non-essential
+    (throw 'non-essential 'non-essential))
   (let* ((use-gateway (ange-ftp-use-gateway-p host))
          (use-smart-ftp (and (not ange-ftp-gateway-host)
                              (ange-ftp-use-smart-gateway-p host)))
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index 47aaa4a8e57..1ef602cf6da 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -4292,6 +4292,11 @@ connection if a previous connection has died for some reason."
             ;; We call `tramp-get-buffer' in order to get a debug
             ;; buffer for messages from the beginning.
             (tramp-get-buffer vec)
+
+            ;; If `non-essential' is non-nil, don't reopen a new connection.
+            (when non-essential
+              (throw 'non-essential 'non-essential))
+
             (tramp-with-progress-reporter
                 vec 3
                 (if (zerop (length (tramp-file-name-user vec)))
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index e9621c5d44e..d0e8b35d6ca 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -1928,22 +1928,32 @@ Falls back to normal file name handler if no Tramp file name handler exists."
                         (let ((default-directory
                                 (tramp-compat-temporary-file-directory)))
                           (load (cadr sf) 'noerror 'nomessage)))
+                      ;; If `non-essential' is non-nil, Tramp shall
+                      ;; not open a new connection.
                       ;; If Tramp detects that it shouldn't continue
-                      ;; to work, it throws the `suppress' event.  We
-                      ;; try the default handler then.
+                      ;; to work, it throws the `suppress' event.
                       ;; This could happen for example, when Tramp
                       ;; tries to open the same connection twice in a
                       ;; short time frame.
+                      ;; In both cases, we try the default handler then.
                       (setq result
-                            (catch 'suppress (apply foreign operation args)))
-                      (if (eq result 'suppress)
-                          (let (tramp-message-show-message)
-                            (tramp-message
-                             v 1 "Suppress received in operation %s"
-                             (append (list operation) args))
-                            (tramp-cleanup v)
-                            (tramp-run-real-handler operation args))
-                        result))
+                            (catch 'non-essential
+                              (catch 'suppress
+                                (apply foreign operation args))))
+                      (cond
+                       ((eq result 'non-essential)
+                        (tramp-message
+                         v 5 "Non-essential received in operation %s"
+                         (append (list operation) args))
+                        (tramp-run-real-handler operation args))
+                       ((eq result 'suppress)
+                        (let (tramp-message-show-message)
+                          (tramp-message
+                           v 1 "Suppress received in operation %s"
+                           (append (list operation) args))
+                          (tramp-cleanup v)
+                          (tramp-run-real-handler operation args)))
+                       (t result)))
 
                   ;; Trace that somebody has interrupted the operation.
                   ((debug quit)