Re: reverting buffer from non-existent file

[martin rudalics]

> - it's probably better to bind inhibit-read-only than buffer-read-only.
> - IIRC buffer-undo-list doesn't need to be bound here since
>   insert-file-contents does it for us anyway.

In the attached patch I followed your suggestions and also simplified
the `revert-without-query' mechanism slightly.  By the way, shouldn't

(set (make-local-variable 'revert-buffer-internal-hook)
                          local-hook)

be handled by add-hook?

*** files.el    Wed Feb  1 10:17:44 2006
--- files.el    Tue Feb  7 20:23:42 2006
***************
*** 3791,3803 ****
  confirmation.)

  Optional third argument PRESERVE-MODES non-nil means don't alter
! the files modes.  Normally we reinitialize them using `normal-mode'.

  If the value of `revert-buffer-function' is non-nil, it is called to
  do all the work for this command.  Otherwise, the hooks
  `before-revert-hook' and `after-revert-hook' are run at the beginning
  and the end, and if `revert-buffer-insert-file-contents-function' is
! non-nil, it is called instead of rereading visited file contents."

    ;; I admit it's odd to reverse the sense of the prefix argument, but
    ;; there is a lot of code out there which assumes that the first
--- 3791,3803 ----
  confirmation.)

  Optional third argument PRESERVE-MODES non-nil means don't alter
! the file's modes.  Normally we reinitialize them using `normal-mode'.

  If the value of `revert-buffer-function' is non-nil, it is called to
  do all the work for this command.  Otherwise, the hooks
  `before-revert-hook' and `after-revert-hook' are run at the beginning
  and the end, and if `revert-buffer-insert-file-contents-function' is
! non-nil, it is called instead of rereading the visited file's contents."

    ;; I admit it's odd to reverse the sense of the prefix argument, but
    ;; there is a lot of code out there which assumes that the first
***************
*** 3823,3835 ****
               (error "Buffer does not seem to be associated with any file"))
              ((or noconfirm
                   (and (not (buffer-modified-p))
!                       (let ((tail revert-without-query)
!                             (found nil))
!                         (while tail
!                           (if (string-match (car tail) file-name)
!                               (setq found t))
!                           (setq tail (cdr tail)))
!                         found))
                   (yes-or-no-p (format "Revert buffer from file %s? "
                                        file-name)))
               (run-hooks 'before-revert-hook)
--- 3823,3832 ----
               (error "Buffer does not seem to be associated with any file"))
              ((or noconfirm
                   (and (not (buffer-modified-p))
!                       (catch 'found
!                         (dolist (regexp revert-without-query)
!                           (when (string-match regexp file-name)
!                             (throw 'found t)))))
                   (yes-or-no-p (format "Revert buffer from file %s? "
                                        file-name)))
               (run-hooks 'before-revert-hook)
***************
*** 3838,3887 ****
               (and (not auto-save-p)
                    (not (verify-visited-file-modtime (current-buffer)))
                    (setq buffer-backed-up nil))
-              ;; Get rid of all undo records for this buffer.
-              (or (eq buffer-undo-list t)
-                  (setq buffer-undo-list nil))
               ;; Effectively copy the after-revert-hook status,
               ;; since after-find-file will clobber it.
               (let ((global-hook (default-value 'after-revert-hook))
                     (local-hook-p (local-variable-p 'after-revert-hook))
                     (local-hook (and (local-variable-p 'after-revert-hook)
!                                     after-revert-hook)))
!                (let (buffer-read-only
!                      ;; Don't make undo records for the reversion.
!                      (buffer-undo-list t))
!                  (if revert-buffer-insert-file-contents-function
!                      (funcall revert-buffer-insert-file-contents-function
!                               file-name auto-save-p)
!                    (if (not (file-exists-p file-name))
!                        (error (if buffer-file-number
!                                   "File %s no longer exists!"
!                                 "Cannot revert nonexistent file %s")
!                               file-name))
!                    ;; Bind buffer-file-name to nil
!                    ;; so that we don't try to lock the file.
!                    (let ((buffer-file-name nil))
!                      (or auto-save-p
!                          (unlock-buffer)))
!                    (widen)
!                    (let ((coding-system-for-read
!                           ;; Auto-saved file shoule be read by Emacs'
!                           ;; internal coding.
!                           (if auto-save-p 'auto-save-coding
!                             (or coding-system-for-read
!                                 buffer-file-coding-system-explicit))))
!                      ;; This force after-insert-file-set-coding
!                      ;; (called from insert-file-contents) to set
!                      ;; buffer-file-coding-system to a proper value.
!                      (kill-local-variable 'buffer-file-coding-system)
! 
!                      ;; Note that this preserves point in an intelligent way.
!                      (if preserve-modes
!                          (let ((buffer-file-format buffer-file-format))
!                            (insert-file-contents file-name (not auto-save-p)
!                                                  nil nil t))
!                        (insert-file-contents file-name (not auto-save-p)
!                                              nil nil t)))))
                 ;; Recompute the truename in case changes in symlinks
                 ;; have changed the truename.
                 (setq buffer-file-truename
--- 3835,3886 ----
               (and (not auto-save-p)
                    (not (verify-visited-file-modtime (current-buffer)))
                    (setq buffer-backed-up nil))
               ;; Effectively copy the after-revert-hook status,
               ;; since after-find-file will clobber it.
               (let ((global-hook (default-value 'after-revert-hook))
                     (local-hook-p (local-variable-p 'after-revert-hook))
                     (local-hook (and (local-variable-p 'after-revert-hook)
!                                     after-revert-hook))
!                    (inhibit-read-only t))
!                (cond
!                 (revert-buffer-insert-file-contents-function
!                  (unless (eq buffer-undo-list t)
!                    ;; Get rid of all undo records for this buffer.
!                    (setq buffer-undo-list nil))
!                  ;; Don't make undo records for the reversion.
!                  (let ((buffer-undo-list t))
!                    (funcall revert-buffer-insert-file-contents-function
!                             file-name auto-save-p)))
!                 ((not (file-exists-p file-name))
!                  (error (if buffer-file-number
!                             "File %s no longer exists!"
!                           "Cannot revert nonexistent file %s")
!                         file-name))
!                 (t
!                  ;; Bind buffer-file-name to nil
!                  ;; so that we don't try to lock the file.
!                  (let ((buffer-file-name nil))
!                    (or auto-save-p
!                        (unlock-buffer)))
!                  (widen)
!                  (let ((coding-system-for-read
!                         ;; Auto-saved file should be read by Emacs'
!                         ;; internal coding.
!                         (if auto-save-p 'auto-save-coding
!                           (or coding-system-for-read
!                               buffer-file-coding-system-explicit))))
!                    ;; This force after-insert-file-set-coding
!                    ;; (called from insert-file-contents) to set
!                    ;; buffer-file-coding-system to a proper value.
!                    (kill-local-variable 'buffer-file-coding-system)
! 
!                    ;; Note that this preserves point in an intelligent way.
!                    (if preserve-modes
!                        (let ((buffer-file-format buffer-file-format))
!                          (insert-file-contents file-name (not auto-save-p)
!                                                nil nil t))
!                      (insert-file-contents file-name (not auto-save-p)
!                                            nil nil t)))))
                 ;; Recompute the truename in case changes in symlinks
                 ;; have changed the truename.
                 (setq buffer-file-truename