Verify the version of Emacsclient.

lib-src/emacsclient.c (main): Send the version number of emacsclient
to the Emacs process, and exit with error if Emacs does not accept it.

lisp/server.el (server-with-errors-reported): Removed.
(server-process-filter): Cleaned up error handling.
Compare the version of emacsclient with emacs-version; 
signal an error if they do not match.

git-archimport-id: lorentey@elte.hu--2004/emacs--multi-tty--0--patch-84

lib-src/emacsclient.c

@@ -562,6 +562,9 @@ To start the server in Emacs, type \"M-x server-start\".\n",
       fail ();
     }
 
+  /* First of all, send our version number for verification. */
+  fprintf (out, "-version %s ", VERSION);
+  
   if (nowait)
     fprintf (out, "-nowait ");
 
@@ -650,7 +653,20 @@ To start the server in Emacs, type \"M-x server-start\".\n",
   /* Now, wait for an answer and print any messages.  */
   while ((str = fgets (string, BUFSIZ, in)))
     {
-      if (strprefix ("-emacs-pid ", str))
+      if (strprefix ("-good-version ", str))
+        {
+          /* OK, we got the green light. */
+        }
+      else if (strprefix ("-bad-version ", str))
+        {
+          if (str[strlen (str) - 1] == '\n')
+            str[strlen (str) - 1] = 0;
+          
+          fprintf (stderr, "%s: Version mismatch: Emacs is %s, but we are %s\n",
+                   argv[0], str + strlen ("-bad-version "), VERSION);
+          fail ();
+        }
+      else if (strprefix ("-emacs-pid ", str))
         {
           emacs_pid = strtol (string + strlen ("-emacs-pid"), NULL, 10);
         }

lisp/server.el

@@ -349,17 +349,6 @@ Server mode runs a process that accepts commands from the
   ;; nothing if there is one (for multiple Emacs sessions)?
   (server-start (not server-mode)))
 
-(defmacro server-with-errors-reported (&rest forms)
-  "Evaluate FORMS; if an error occurs, report it to the client
-and return nil.  Otherwise, return the result of the last form.
-For use in server-process-filter only."
-  `(condition-case err
-       (progn ,@forms)
-     (error (ignore-errors
-	      (process-send-string
-	       proc (concat "-error " (error-message-string err)))
-	      (setq request "")))))
-
 (defun server-process-filter (proc string)
   "Process a request from the server to edit some files.
 PROC is the server process.  Format of STRING is \"PATH PATH PATH... \\n\"."
@@ -368,6 +357,7 @@ PROC is the server process.  Format of STRING is \"PATH PATH PATH... \\n\"."
     (when prev
       (setq string (concat prev string))
       (process-put proc 'previous-string nil)))
+  (condition-case err
       ;; If the input is multiple lines,
       ;; process each line individually.
       (while (string-match "\n" string)
@@ -375,7 +365,7 @@ PROC is the server process.  Format of STRING is \"PATH PATH PATH... \\n\"."
 	      (coding-system (and default-enable-multibyte-characters
 				  (or file-name-coding-system
 				      default-file-name-coding-system)))
-	  client nowait eval newframe display
+	      client nowait eval newframe display version-checked
 	      registered	; t if the client is already added to server-clients.
 	      (files nil)
 	      (lineno 1)
@@ -387,6 +377,17 @@ PROC is the server process.  Format of STRING is \"PATH PATH PATH... \\n\"."
 	    (let ((arg (substring request (match-beginning 0) (1- (match-end 0)))))
 	      (setq request (substring request (match-end 0)))
 	      (cond
+	       ;; Check version numbers.
+	       ((and (equal "-version" arg) (string-match "\\([0-9.]+\\) " request))
+		(let* ((client-version (match-string 1 request))
+		       (truncated-emacs-version (substring emacs-version 0 (length client-version))))
+		  (setq request (substring request (match-end 0)))
+		  (if (equal client-version truncated-emacs-version)
+		      (progn
+			(process-send-string proc "-good-version \n")
+			(setq version-checked t))
+		    (error (concat "Version mismatch: Emacs is " truncated-emacs-version ", emacsclient is " client-version)))))
+
 	       ((equal "-nowait" arg) (setq nowait t))
 	       ((equal "-eval" arg) (setq eval t))
 
@@ -396,7 +397,8 @@ PROC is the server process.  Format of STRING is \"PATH PATH PATH... \\n\"."
 
 	       ;; Open a new X frame.
 	       ((equal "-window-system" arg)
-	    (server-with-errors-reported
+		(unless version-checked
+		  (error "Protocol error; make sure to use the correct version of emacsclient"))
 		(let ((frame (make-frame-on-display
 			      (or display
 				  (frame-parameter nil 'display)
@@ -407,14 +409,15 @@ PROC is the server process.  Format of STRING is \"PATH PATH PATH... \\n\"."
 		  ;; This makes sure that `emacsclient -w -e '(delete-frame)'' works right.
 		  (push client server-clients)
 		  (setq registered t
-		     newframe t))))
+			newframe t)))
 
 	       ;; Open a new tty frame at the client.  ARG is the name of the pseudo tty.
 	       ((and (equal "-tty" arg) (string-match "\\([^ ]*\\) \\([^ ]*\\) " request))
 		(let ((tty (server-unquote-arg (match-string 1 request)))
 		      (type (server-unquote-arg (match-string 2 request))))
 		  (setq request (substring request (match-end 0)))
-	      (server-with-errors-reported
+		  (unless version-checked
+		    (error "Protocol error; make sure to use the correct version of emacsclient"))
 		  (let ((frame (make-frame-on-tty tty type)))
 		    (push (list (car client) (frame-tty-name frame)) server-ttys)
 		    (process-send-string proc (concat "-emacs-pid " (number-to-string (emacs-pid)) "\n"))
@@ -422,7 +425,7 @@ PROC is the server process.  Format of STRING is \"PATH PATH PATH... \\n\"."
 		    ;; This makes sure that `emacsclient -t -e '(delete-frame)'' works right.
 		    (push client server-clients)
 		    (setq registered t
-		       newframe t)))))
+			  newframe t))))
 
 	       ;; ARG is a line number option.
 	       ((string-match "\\`\\+[0-9]+\\'" arg)
@@ -435,23 +438,23 @@ PROC is the server process.  Format of STRING is \"PATH PATH PATH... \\n\"."
 
 	       ;; ARG is a filename or a Lisp expression.
 	       (t
-
 		;; Undo the quoting that emacsclient does
 		;; for certain special characters.
 		(setq arg (server-unquote-arg arg))
 		;; Now decode the file name if necessary.
 		(if coding-system
 		    (setq arg (decode-coding-string arg coding-system)))
+		(unless version-checked
+		  (error "Protocol error; make sure to use the correct version of emacsclient"))
 		(if eval
-		(server-with-errors-reported
+		    ;; ARG is a Lisp expression.
 		    (let ((v (eval (car (read-from-string arg)))))
 		      (when (and (not newframe) v)
 			(with-temp-buffer
 			  (let ((standard-output (current-buffer)))
 			    (pp v)
 			    (process-send-string proc "-print ")
-			 (process-send-region proc (point-min) (point-max)))))))
-
+			    (process-send-region proc (point-min) (point-max))))))
 		  ;; ARG is a file name.
 		  ;; Collapse multiple slashes to single slashes.
 		  (setq arg (command-line-normalize-file-name arg))
@@ -459,6 +462,8 @@ PROC is the server process.  Format of STRING is \"PATH PATH PATH... \\n\"."
 		(setq lineno 1)
 		(setq columnno 0)))))
 
+	  (if (not version-checked)
+	      (error "Protocol error; make sure to use the correct version of emacsclient")
 	    (when files
 	      (run-hooks 'pre-command-hook)
 	      (server-visit-files files client nowait)
@@ -483,6 +488,13 @@ PROC is the server process.  Format of STRING is \"PATH PATH PATH... \\n\"."
 	;; Save for later any partial line that remains.
 	(when (> (length string) 0)
 	  (process-put proc 'previous-string string)))
+    ;; condition-case
+    (error (ignore-errors
+	     (process-send-string
+	      proc (concat "-error " (error-message-string err)))
+	     (setq string "")
+	     (server-log (error-message-string err) proc)
+	     (delete-process proc)))))
 
 (defun server-goto-line-column (file-line-col)
   (goto-line (nth 1 file-line-col))