Fix next-file command in etags.el.

* lisp/progmodes/etags.el (next-file): Don't use set-buffer to change
buffers (Bug#8478).

* doc/lisp/maintaining.texi (List Tags): Document next-file.

doc/emacs/ChangeLog

@@ -1,3 +1,8 @@
+2011-04-24  Chong Yidong  <cyd@stupidchicken.com>
+
+	* maintaining.texi (List Tags): Document next-file.  Suggested by
+	Uday S Reddy.
+
 2011-04-23  Juanma Barranquero  <lekktu@gmail.com>
 
 	* mini.texi (Minibuffer Edit):

doc/emacs/maintaining.texi

@@ -2326,6 +2326,12 @@ details.
   You can also use the collection of tag names to complete a symbol
 name in the buffer.  @xref{Symbol Completion}.
 
+  You can use @kbd{M-x next-file} to visit the files in the selected
+tags table.  The first time this command is called, it visits the
+first file in the tags table.  Each subsequent call visits the next
+file in the table, unless a prefix argument is supplied, in which case
+it returns to the first file.
+
 @node EDE
 @section Emacs Development Environment
 @cindex EDE (Emacs Development Environment)

lisp/ChangeLog

@@ -1,3 +1,8 @@
+2011-04-24  Uday S Reddy  <u.s.reddy@cs.bham.ac.uk>  (tiny change)
+
+	* progmodes/etags.el (next-file): Don't use set-buffer to change
+	buffers (Bug#8478).
+
 2011-04-24  Chong Yidong  <cyd@stupidchicken.com>
 
 	* files.el (auto-mode-alist): Use js-mode for .json (Bug#8529).

lisp/progmodes/etags.el

@@ -1756,9 +1756,9 @@ if the file was newly read in, the value is the filename."
 	 (with-current-buffer buffer
 	   (revert-buffer t t)))
     (if (not (and new novisit))
-	(set-buffer (find-file-noselect next novisit))
+	(find-file next novisit)
       ;; Like find-file, but avoids random warning messages.
-      (set-buffer (get-buffer-create " *next-file*"))
+      (switch-to-buffer (get-buffer-create " *next-file*"))
       (kill-all-local-variables)
       (erase-buffer)
       (setq new next)