In Tramp. check ssh Control* options only when needed

Fixes: debbugs:20015

* net/tramp-adb.el:
* net/tramp-gvfs.el:
* net/tramp-sh.el:
* net/tramp-smb.el: Set tramp-autoload cookie for all defcustoms.

* net/tramp-sh.el (tramp-use-ssh-controlmaster-options):
New defcustom, moved from tramp.el.
(tramp-ssh-controlmaster-options): New defvar, moved from tramp.el
but with a nil initial value.
(tramp-ssh-controlmaster-options): New defun.
(tramp-do-copy-or-rename-file-out-of-band)
(tramp-maybe-open-connection): Use it.

* net/tramp.el (tramp-ssh-controlmaster-options)
(tramp-use-ssh-controlmaster-options): Move them to tramp-sh.el.
(tramp-default-method): Do not check for
`tramp-ssh-controlmaster-options'.

6 files changed, 101 insertions, 46 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 73ba0353d9d..747a1d6c650 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,23 @@
+2015-03-15  Michael Albinus  <michael.albinus@gmx.de>
+
+        * net/tramp-adb.el:
+        * net/tramp-gvfs.el:
+        * net/tramp-sh.el:
+        * net/tramp-smb.el: Set tramp-autoload cookie for all defcustoms.
+
+        * net/tramp.el (tramp-ssh-controlmaster-options)
+        (tramp-use-ssh-controlmaster-options): Move them to tramp-sh.el.
+        (tramp-default-method): Do not check for
+        `tramp-ssh-controlmaster-options'.
+
+        * net/tramp-sh.el (tramp-use-ssh-controlmaster-options):
+        New defcustom, moved from tramp.el.
+        (tramp-ssh-controlmaster-options): New defvar, moved from tramp.el
+        but with a nil initial value.
+        (tramp-ssh-controlmaster-options): New defun.
+        (tramp-do-copy-or-rename-file-out-of-band)
+        (tramp-maybe-open-connection): Use it.  (Bug#20015)
+
 2015-03-15  Tassilo Horn  <tsdh@gnu.org>
 
         * emacs-lisp/lisp-mode.el (lisp--el-macro-regexp): New defconst.
diff --git a/lisp/net/tramp-adb.el b/lisp/net/tramp-adb.el
index 6696dcf1505..a92ca4df51c 100644
--- a/lisp/net/tramp-adb.el
+++ b/lisp/net/tramp-adb.el
@@ -38,12 +38,14 @@
 ;; Pacify byte-compiler.
 (defvar directory-sep-char)
 
+;;;###tramp-autoload
 (defcustom tramp-adb-program "adb"
   "Name of the Android Debug Bridge program."
   :group 'tramp
   :version "24.4"
   :type 'string)
 
+;;;###tramp-autoload
 (defcustom tramp-adb-connect-if-not-connected nil
   "Try to run `adb connect' if provided device is not connected currently.
 It is used for TCP/IP devices."
@@ -55,6 +57,7 @@ It is used for TCP/IP devices."
 (defconst tramp-adb-method "adb"
   "*When this method name is used, forward all calls to Android Debug Bridge.")
 
+;;;###tramp-autoload
 (defcustom tramp-adb-prompt
   "^\\(?:[[:digit:]]*|?\\)?\\(?:[[:alnum:]]*@[[:alnum:]]*[^#\\$]*\\)?[#\\$][[:space:]]"
   "Regexp used as prompt in almquist shell."
diff --git a/lisp/net/tramp-gvfs.el b/lisp/net/tramp-gvfs.el
index 1ea52eb670d..5988a284c6e 100644
--- a/lisp/net/tramp-gvfs.el
+++ b/lisp/net/tramp-gvfs.el
@@ -127,6 +127,7 @@
 ;;;###tramp-autoload
 (add-to-list 'tramp-default-user-alist '("\\`synce\\'" nil nil))
 
+;;;###tramp-autoload
 (defcustom tramp-gvfs-zeroconf-domain "local"
   "Zeroconf domain to be used for discovering services, like host names."
   :group 'tramp
@@ -374,6 +375,7 @@ It has been changed in GVFS 1.14.")
 ;;   </signal>
 ;; </interface>
 
+;;;###tramp-autoload
 (defcustom tramp-bluez-discover-devices-timeout 60
   "Defines seconds since last bluetooth device discovery before rescanning.
 A value of 0 would require an immediate discovery during hostname
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index 76d2b014917..73ad8c7e4ef 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -40,6 +40,7 @@
 (defvar vc-git-program)
 (defvar vc-hg-program)
 
+;;;###tramp-autoload
 (defcustom tramp-inline-compress-start-size 4096
   "The minimum size of compressing where inline transfer.
 When inline transfer, compress transferred data of file
@@ -48,6 +49,7 @@ If it is nil, no compression at all will be applied."
   :group 'tramp
   :type '(choice (const nil) integer))
 
+;;;###tramp-autoload
 (defcustom tramp-copy-size-limit 10240
   "The maximum file size where inline copying is preferred over an \
 out-of-the-band copy.
@@ -105,6 +107,27 @@ detected as prompt when being sent on echoing hosts, therefore.")
 (defconst tramp-end-of-heredoc (md5 tramp-end-of-output)
   "String used to recognize end of heredoc strings.")
 
+;;;###tramp-autoload
+(defcustom tramp-use-ssh-controlmaster-options t
+  "Whether to use `tramp-ssh-controlmaster-options'."
+  :group 'tramp
+  :version "24.4"
+  :type 'boolean)
+
+(defvar tramp-ssh-controlmaster-options nil
+  "Which ssh Control* arguments to use.
+
+If it is a string, it should have the form
+\"-o ControlMaster=auto -o ControlPath='tramp.%%r@%%h:%%p'
+-o ControlPersist=no\".  Percent characters in the ControlPath
+spec must be doubled, because the string is used as format string.
+
+Otherwise, it will be auto-detected by Tramp, if
+`tramp-use-ssh-controlmaster-options' is non-nil.  The value
+depends on the installed local ssh version.
+
+The string is used in `tramp-methods'.")
+
 ;; Initialize `tramp-methods' with the supported methods.
 ;;;###tramp-autoload
 (add-to-list 'tramp-methods
@@ -489,6 +512,7 @@ not be set here. Instead, it should be set via `tramp-remote-path'."
   :version "24.4"
   :type '(repeat string))
 
+;;;###tramp-autoload
 (defcustom tramp-sh-extra-args '(("/bash\\'" . "-norc -noprofile"))
   "Alist specifying extra arguments to pass to the remote shell.
 Entries are (REGEXP . ARGS) where REGEXP is a regular expression
@@ -2354,10 +2378,7 @@ The method used must be an out-of-band method."
               spec (format-spec-make
                     ?t (tramp-get-connection-property
                         (tramp-get-connection-process v) "temp-file" ""))
-              options (format-spec
-                       (if tramp-use-ssh-controlmaster-options
-                           tramp-ssh-controlmaster-options "")
-                       spec)
+              options (format-spec (tramp-ssh-controlmaster-options v) spec)
               spec (format-spec-make
                     ?h host ?u user ?p port ?r listener ?c options
                     ?k (if keep-date " " ""))
@@ -4566,6 +4587,49 @@ Gateway hops are already opened."
     ;; Result.
     target-alist))
 
+(defun tramp-ssh-controlmaster-options (vec)
+  "Return the Control* arguments of the local ssh."
+  (cond
+   ;; No options to be computed.
+   ((or (null tramp-use-ssh-controlmaster-options)
+        (null (assoc "%c" (tramp-get-method-parameter
+                           (tramp-file-name-method vec) 'tramp-login-args))))
+    "")
+
+   ;; There is already a value to be used.
+   ((stringp tramp-ssh-controlmaster-options) tramp-ssh-controlmaster-options)
+
+   ;; Determine the options.
+   (t (setq tramp-ssh-controlmaster-options "")
+      (let ((case-fold-search t))
+        (ignore-errors
+          (when (executable-find "ssh")
+            (with-temp-buffer
+              (tramp-call-process vec "ssh" nil t nil "-o" "ControlMaster")
+              (goto-char (point-min))
+              (when (search-forward-regexp "missing.+argument" nil t)
+                (setq tramp-ssh-controlmaster-options "-o ControlMaster=auto")))
+            (unless (zerop (length tramp-ssh-controlmaster-options))
+              (with-temp-buffer
+                (tramp-call-process
+                 vec "ssh" nil t nil
+                 "-o" "ControlPath=%C" "host.does.not.exist")
+                (goto-char (point-min))
+                (setq tramp-ssh-controlmaster-options
+                      (if (search-forward-regexp "unknown.+key" nil t)
+                          (concat tramp-ssh-controlmaster-options
+                                  " -o ControlPath='tramp.%%r@%%h:%%p'")
+                        (concat tramp-ssh-controlmaster-options
+                                " -o ControlPath='tramp.%%C'"))))
+              (with-temp-buffer
+                (tramp-call-process vec "ssh" nil t nil "-o" "ControlPersist")
+                (goto-char (point-min))
+                (when (search-forward-regexp "missing.+argument" nil t)
+                  (setq tramp-ssh-controlmaster-options
+                        (concat tramp-ssh-controlmaster-options
+                                " -o ControlPersist=no"))))))))
+      tramp-ssh-controlmaster-options)))
+
 (defun tramp-maybe-open-connection (vec)
   "Maybe open a connection VEC.
 Does not do anything if a connection is already open, but re-opens the
@@ -4647,8 +4711,7 @@ connection if a previous connection has died for some reason."
               (let* ((target-alist (tramp-compute-multi-hops vec))
                      ;; We will apply `tramp-ssh-controlmaster-options'
                      ;; only for the first hop.
-                     (options (if tramp-use-ssh-controlmaster-options
-                                  tramp-ssh-controlmaster-options ""))
+                     (options (tramp-ssh-controlmaster-options vec))
                      (process-connection-type tramp-process-connection-type)
                      (process-adaptive-read-buffering nil)
                      (coding-system-for-read nil)
diff --git a/lisp/net/tramp-smb.el b/lisp/net/tramp-smb.el
index d5fe17f0939..14360b96fe6 100644
--- a/lisp/net/tramp-smb.el
+++ b/lisp/net/tramp-smb.el
@@ -70,17 +70,20 @@
     tramp-smb-method
     '((tramp-parse-netrc "~/.netrc"))))
 
+;;;###tramp-autoload
 (defcustom tramp-smb-program "smbclient"
   "Name of SMB client to run."
   :group 'tramp
   :type 'string)
 
+;;;###tramp-autoload
 (defcustom tramp-smb-acl-program "smbcacls"
   "Name of SMB acls to run."
   :group 'tramp
   :type 'string
   :version "24.4")
 
+;;;###tramp-autoload
 (defcustom tramp-smb-conf "/dev/null"
   "Path of the smb.conf file.
 If it is nil, no smb.conf will be added to the `tramp-smb-program'
@@ -280,6 +283,7 @@ See `tramp-actions-before-shell' for more info.")
 Operations not mentioned here will be handled by the default Emacs primitives.")
 
 ;; Options for remote processes via winexe.
+;;;###tramp-autoload
 (defcustom tramp-smb-winexe-program "winexe"
   "Name of winexe client to run.
 If it isn't found in the local $PATH, the absolute path of winexe
@@ -288,6 +292,7 @@ shall be given.  This is needed for remote processes."
   :type 'string
   :version "24.3")
 
+;;;###tramp-autoload
 (defcustom tramp-smb-winexe-shell-command "powershell.exe"
   "Shell to be used for processes on remote machines.
 This must be Powershell V2 compatible."
@@ -295,6 +300,7 @@ This must be Powershell V2 compatible."
   :type 'string
   :version "24.3")
 
+;;;###tramp-autoload
 (defcustom tramp-smb-winexe-shell-command-switch "-file -"
   "Command switch used together with `tramp-smb-winexe-shell-command'.
 This can be used to disable echo etc."
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index 953525f37e4..10bb76983aa 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -307,43 +307,6 @@ started on the local host.  You should specify a remote host
 `localhost' or the name of the local host.  Another host name is
 useful only in combination with `tramp-default-proxies-alist'.")
 
-;;;###tramp-autoload
-(defconst tramp-ssh-controlmaster-options
-  (let ((result "")
-        (case-fold-search t))
-    (ignore-errors
-      (when (executable-find "ssh")
-        (with-temp-buffer
-          (call-process "ssh" nil t nil "-o" "ControlMaster")
-          (goto-char (point-min))
-          (when (search-forward-regexp "missing.+argument" nil t)
-            (setq result "-o ControlMaster=auto")))
-        (unless (zerop (length result))
-          (with-temp-buffer
-            (call-process
-             "ssh" nil t nil "-o" "ControlPath=%C" "host.does.not.exist")
-            (goto-char (point-min))
-            (if (search-forward-regexp "unknown.+key" nil t)
-                (setq result
-                      (concat result " -o ControlPath='tramp.%%r@%%h:%%p'"))
-              (setq result (concat result " -o ControlPath='tramp.%%C'"))))
-          (with-temp-buffer
-            (call-process "ssh" nil t nil "-o" "ControlPersist")
-            (goto-char (point-min))
-            (when (search-forward-regexp "missing.+argument" nil t)
-              (setq result (concat result " -o ControlPersist=no")))))))
-    result)
-    "Call ssh to detect whether it supports the Control* arguments.
-Return a string to be used in `tramp-methods'.")
-
-;;;###tramp-autoload
-(defcustom tramp-use-ssh-controlmaster-options
-  (not (zerop (length tramp-ssh-controlmaster-options)))
-  "Whether to use `tramp-ssh-controlmaster-options'."
-  :group 'tramp
-  :version "24.4"
-  :type 'boolean)
-
 (defcustom tramp-default-method
   ;; An external copy method seems to be preferred, because it performs
   ;; much better for large files, and it hasn't too serious delays
@@ -374,9 +337,7 @@ Return a string to be used in `tramp-methods'.")
             (fboundp 'auth-source-search)
             ;; ssh-agent is running.
             (getenv "SSH_AUTH_SOCK")
-            (getenv "SSH_AGENT_PID")
-            ;; We could reuse the connection.
-            (> (length tramp-ssh-controlmaster-options) 0))
+            (getenv "SSH_AGENT_PID"))
         "scp"
       "ssh"))
    ;; Fallback.