toggle-read-only fixes for bugs#7292, 10006.

* doc/lispref/buffers.texi (Read Only Buffers): Expand a bit on why
toggle-read-only should only be used interactively.

* lisp/files.el (toggle-read-only): Mention that it should only
be used interactively.

* lisp/emacs-lisp/bytecomp.el (byte-compile-interactive-only-functions):
Add toggle-read-only.

doc/lispref/ChangeLog

+2011-11-10  Glenn Morris  <rgm@gnu.org>
+
+	* buffers.texi (Read Only Buffers): Expand a bit on why
+	toggle-read-only should only be used interactively.  (Bug#7292)
+
 2011-11-09  Chong Yidong  <cyd@gnu.org>
 
 	* windows.texi (Window Sizes): Document window-pixel-edges,

doc/lispref/buffers.texi

@@ -748,10 +748,11 @@ of the list (comparison is done with @code{eq}).
 
 @deffn Command toggle-read-only &optional arg
 This command toggles whether the current buffer is read-only.  It is
-intended for interactive use; do not use it in programs.  At any given
-point in a program, you should know whether you want the read-only flag
-on or off; so you can set @code{buffer-read-only} explicitly to the
-proper value, @code{t} or @code{nil}.
+intended for interactive use; do not use it in programs (it may have
+side-effects, such as enabling View mode, and does not affect
+read-only text properties).  To change the read-only state of a buffer in
+a program, explicitly set @code{buffer-read-only} to the proper value.
+To temporarily ignore a read-only state, bind @code{inhibit-read-only}.
 
 If @var{arg} is non-@code{nil}, it should be a raw prefix argument.
 @code{toggle-read-only} sets @code{buffer-read-only} to @code{t} if

lisp/ChangeLog

+2011-11-10  Glenn Morris  <rgm@gnu.org>
+
+	* emacs-lisp/bytecomp.el (byte-compile-interactive-only-functions):
+	Add toggle-read-only.  (Bug#7292)
+	* files.el (toggle-read-only): Mention that it should only
+	be used interactively.  (Bug#10006)
+
 2011-11-09  Stefan Monnier  <monnier@iro.umontreal.ca>
 
 	* progmodes/compile.el (compilation-error-regexp-alist-alist):

lisp/emacs-lisp/bytecomp.el

@@ -355,7 +355,7 @@ else the global value will be modified."
 (defvar byte-compile-interactive-only-functions
   '(beginning-of-buffer end-of-buffer replace-string replace-regexp
     insert-file insert-buffer insert-file-literally previous-line next-line
-    goto-line comint-run delete-backward-char)
+    goto-line comint-run delete-backward-char toggle-read-only)
   "List of commands that are not meant to be called from Lisp.")
 
 (defvar byte-compile-not-obsolete-vars nil

lisp/files.el

@@ -4686,7 +4686,15 @@ prints a message in the minibuffer.  Instead, use `set-buffer-modified-p'."
   "Change whether this buffer is read-only.
 With prefix argument ARG, make the buffer read-only if ARG is
 positive, otherwise make it writable.  If buffer is read-only
-and `view-read-only' is non-nil, enter view mode."
+and `view-read-only' is non-nil, enter view mode.
+
+This function is usually the wrong thing to use in a Lisp program.
+It can have side-effects beyond changing the read-only status of a buffer
+\(e.g., enabling view mode), and does not affect read-only regions that
+are caused by text properties.  To make a buffer read-only in Lisp code,
+set `buffer-read-only'.  To ignore read-only status (whether due to text
+properties or buffer state) and make changes, temporarily bind
+`inhibit-read-only'."
   (interactive "P")
   (if (and arg
            (if (> (prefix-numeric-value arg) 0) buffer-read-only