2 files changed, 75 insertions, 62 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index f199102295a..69451ce5349 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,10 @@
+2012-08-08  Michael Albinus  <michael.albinus@gmx.de>
+
+        * net/tramp-sh.el (tramp-find-file-exists-command): Protect the
+        tests by `ignore-error'.
+        (tramp-find-shell): Open also a new shell, when cache is already
+        set.  Reported by Carsten Bormann <cabo@tzi.org>.  (Bug#12148)
+
 2012-08-08  Juri Linkov  <juri@jurta.org>
 
         * bookmark.el: Add `defaults' property to the bookmark record.
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index afb25509e4f..a92f4231700 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -3559,26 +3559,30 @@ file exists and nonzero exit status otherwise."
     ;;                    `/usr/bin/test'.
     ;; `/usr/bin/test -e' In case `/bin/test' does not exist.
     (unless (or
-             (and (setq result (format "%s -e" (tramp-get-test-command vec)))
-                  (tramp-send-command-and-check
-                   vec (format "%s %s" result existing))
-                  (not (tramp-send-command-and-check
-                        vec (format "%s %s" result nonexistent))))
-             (and (setq result "/bin/test -e")
-                  (tramp-send-command-and-check
-                   vec (format "%s %s" result existing))
-                  (not (tramp-send-command-and-check
-                        vec (format "%s %s" result nonexistent))))
-             (and (setq result "/usr/bin/test -e")
-                  (tramp-send-command-and-check
-                   vec (format "%s %s" result existing))
-                  (not (tramp-send-command-and-check
-                        vec (format "%s %s" result nonexistent))))
-             (and (setq result (format "%s -d" (tramp-get-ls-command vec)))
-                  (tramp-send-command-and-check
-                   vec (format "%s %s" result existing))
-                  (not (tramp-send-command-and-check
-                        vec (format "%s %s" result nonexistent)))))
+             (ignore-errors
+               (and (setq result (format "%s -e" (tramp-get-test-command vec)))
+                    (tramp-send-command-and-check
+                     vec (format "%s %s" result existing))
+                    (not (tramp-send-command-and-check
+                          vec (format "%s %s" result nonexistent)))))
+             (ignore-errors
+               (and (setq result "/bin/test -e")
+                    (tramp-send-command-and-check
+                     vec (format "%s %s" result existing))
+                    (not (tramp-send-command-and-check
+                          vec (format "%s %s" result nonexistent)))))
+             (ignore-errors
+               (and (setq result "/usr/bin/test -e")
+                    (tramp-send-command-and-check
+                     vec (format "%s %s" result existing))
+                    (not (tramp-send-command-and-check
+                          vec (format "%s %s" result nonexistent)))))
+             (ignore-errors
+               (and (setq result (format "%s -d" (tramp-get-ls-command vec)))
+                    (tramp-send-command-and-check
+                     vec (format "%s %s" result existing))
+                    (not (tramp-send-command-and-check
+                          vec (format "%s %s" result nonexistent))))))
       (tramp-error
        vec 'file-error "Couldn't find command to check if file exists"))
     result))
@@ -3609,48 +3613,50 @@ file exists and nonzero exit status otherwise."
 
 (defun tramp-find-shell (vec)
   "Opens a shell on the remote host which groks tilde expansion."
-  (with-connection-property vec "remote-shell"
-    (let ((shell (tramp-get-method-parameter
-                  (tramp-file-name-method vec) 'tramp-remote-shell)))
-      (with-current-buffer (tramp-get-buffer vec)
-        ;; CCC: "root" does not exist always, see QNAP 459.  Which
-        ;; check could we apply instead?
-        (tramp-send-command vec "echo ~root" t)
-        (when (or (string-match "^~root$" (buffer-string))
-                  ;; The default shell (ksh93) of OpenSolaris and
-                  ;; Solaris is buggy.  We've got reports for "SunOS
-                  ;; 5.10" and "SunOS 5.11" so far.
-                  (string-match (regexp-opt '("SunOS 5.10" "SunOS 5.11"))
-                                (tramp-get-connection-property vec "uname" "")))
-          (if (setq shell
-                    (or (tramp-find-executable
-                         vec "bash" (tramp-get-remote-path vec) t t)
-                        (tramp-find-executable
-                         vec "ksh" (tramp-get-remote-path vec) t t)))
-              (progn
-                (tramp-message
-                 vec 5 "Starting remote shell `%s' for tilde expansion" shell)
-                (tramp-open-shell vec shell))
-
-            ;; Maybe it works at least for some other commands.
-            (setq shell
-                  (tramp-get-method-parameter
-                   (tramp-file-name-method vec) 'tramp-remote-shell))
-            (tramp-message
-             vec 2
-             (concat
-              "Couldn't find a remote shell which groks tilde expansion, "
-              "using `%s'")
-             shell)))
-
-        ;; Busyboxes tend to behave strange.  We check for the existence.
-        (with-connection-property vec "busybox"
-          (tramp-send-command vec (format "%s --version" shell) t)
-          (let ((case-fold-search t))
-            (and (string-match "busybox" (buffer-string)) t)))
+  (with-current-buffer (tramp-get-buffer vec)
+    (let ((default-shell (tramp-get-method-parameter
+                          (tramp-file-name-method vec) 'tramp-remote-shell))
+          shell)
+      (setq shell
+            (with-connection-property vec "remote-shell"
+              ;; CCC: "root" does not exist always, see QNAP 459.
+              ;; Which check could we apply instead?
+              (tramp-send-command vec "echo ~root" t)
+              (if (or (string-match "^~root$" (buffer-string))
+                      ;; The default shell (ksh93) of OpenSolaris and
+                      ;; Solaris is buggy.  We've got reports for
+                      ;; "SunOS 5.10" and "SunOS 5.11" so far.
+                      (string-match (regexp-opt '("SunOS 5.10" "SunOS 5.11"))
+                                    (tramp-get-connection-property
+                                     vec "uname" "")))
+
+                  (or (tramp-find-executable
+                       vec "bash" (tramp-get-remote-path vec) t t)
+                      (tramp-find-executable
+                       vec "ksh" (tramp-get-remote-path vec) t t)
+                      ;; Maybe it works at least for some other commands.
+                      (prog1
+                          default-shell
+                        (tramp-message
+                         vec 2
+                         (concat
+                          "Couldn't find a remote shell which groks tilde "
+                          "expansion, using `%s'")
+                         default-shell)))
+
+                default-shell)))
+
+      ;; Open a new shell if needed.
+      (unless (string-equal shell default-shell)
+        (tramp-message
+         vec 5 "Starting remote shell `%s' for tilde expansion" shell)
+        (tramp-open-shell vec shell))
 
-        ;; Return the shell.
-        shell))))
+      ;; Busyboxes tend to behave strange.  We check for the existence.
+      (with-connection-property vec "busybox"
+        (tramp-send-command vec (format "%s --version" shell) t)
+        (let ((case-fold-search t))
+          (and (string-match "busybox" (buffer-string)) t))))))
 
 ;; Utility functions.
 
@@ -3786,7 +3792,7 @@ process to set up.  VEC specifies the connection."
   (tramp-set-remote-path vec)
 
   ;; Search for a good shell before searching for a command which
-  ;; checks if a file exists. This is done because Tramp wants to use
+  ;; checks if a file exists.  This is done because Tramp wants to use
   ;; "test foo; echo $?" to check if various conditions hold, and
   ;; there are buggy /bin/sh implementations which don't execute the
   ;; "echo $?"  part if the "test" part has an error.  In particular,