C-x C-w trouble

[Luc Teirlinck]

The following change:

  * files.el (set-visited-file-name): Report the error
    for "empty filename" earlier.

has problems.

Do `emacs -q -nbc'
C-x C-w
Call your new file "test", or whatever.
Result:
set-visited-file-name: Wrong type argument: stringp, nil

The small patch below fixes the problem, but since I do not know the
reason for the recent change, I am not sure that it is correct.  I can
install if it looks OK.

The problem is that buffer-file-name is nil for the *scratch* buffer
and (file-name-nondirectory nil) yields the above error.

===File ~/files.el-diff=====================================
*** files.el    08 Jul 2005 17:47:33 -0500      1.778
--- files.el    08 Jul 2005 21:03:17 -0500      
***************
*** 2545,2551 ****
          (if find-file-visit-truename
              (setq filename truename))))
      (if filename
!       (let ((new-name (file-name-nondirectory buffer-file-name)))
          (if (string= new-name "")
              (error "Empty file name"))))
      (let ((buffer (and filename (find-buffer-visiting filename))))
--- 2545,2551 ----
          (if find-file-visit-truename
              (setq filename truename))))
      (if filename
!       (let ((new-name (file-name-nondirectory filename)))
          (if (string= new-name "")
              (error "Empty file name"))))
      (let ((buffer (and filename (find-buffer-visiting filename))))
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