If current buffer is a TRAMP buffer, use it's filename for SSH tunnel

Author: Vadim Rodionov

nrepl-client.el

@@ -569,14 +569,21 @@ If NO-ERROR is non-nil, show messages instead of throwing an error."
 
 (defun nrepl--ssh-tunnel-connect (host port)
   "Connect to a remote machine identified by HOST and PORT through SSH tunnel."
-  (message "[nREPL] Establishing SSH tunneled connection to %s:%s ..." host port)
-  (let* ((remote-dir (if host (format "/ssh:%s:" host) default-directory))
+  (let* ((current-buf (buffer-file-name))
+         (tramp-file-regexp "/ssh:\\(.+@\\)?\\(.+?\\)\\(:\\|#\\).+")
+         (remote-dir (cond
+                      ((string-match tramp-file-regexp current-buf) current-buf)
+                      (host (format "/ssh:%s:" host))
+                      (t default-directory)))
+         (remote-host (or (match-string 2 current-buf)
+                          host))
          (ssh (or (executable-find "ssh")
                   (error "[nREPL] Cannot locate 'ssh' executable")))
          (cmd (nrepl--ssh-tunnel-command ssh remote-dir port))
          (tunnel-buf (nrepl-tunnel-buffer-name
-                      `((:host ,host) (:port ,port))))
+                      `((:host ,remote-host) (:port ,port))))
          (tunnel (start-process-shell-command "nrepl-tunnel" tunnel-buf cmd)))
+    (message "[nREPL] Establishing SSH tunneled connection to %s:%s ..." remote-host port)
     (process-put tunnel :waiting-for-port t)
     (set-process-filter tunnel (nrepl--ssh-tunnel-filter port))
     (while (and (process-live-p tunnel)
@@ -589,7 +596,7 @@ If NO-ERROR is non-nil, show messages instead of throwing an error."
         (thread-first
           endpoint
           (plist-put :tunnel tunnel)
-          (plist-put :remote-host host))))))
+          (plist-put :remote-host remote-host))))))
 
 (defun nrepl--ssh-tunnel-command (ssh dir port)
   "Command string to open SSH tunnel to the host associated with DIR's PORT."
@@ -598,11 +605,12 @@ If NO-ERROR is non-nil, show messages instead of throwing an error."
     ;; forwarding is set up, which is used to synchronise on, so that
     ;; the port forwarding is up when we try to connect.
     (format-spec
-     "%s -v -N -L %p:localhost:%p %u'%h'"
+     "%s -v -N -L %p:localhost:%p %u'%h' %n"
      `((?s . ,ssh)
        (?p . ,port)
        (?h . ,v-host)
-       (?u . ,(if v-user (format "-l '%s' " v-user) ""))))))
+       (?u . ,(if v-user (format "-l '%s' " v-user) ""))
+       (?n . ,(if v-port (format "-p '%s' " v-port) ""))))))
 
 (autoload 'comint-watch-for-password-prompt "comint"  "(autoload).")