(read-directory-name): Always pass non-nil

DEFAULT-FILENAME arg to read-file-name.
(backup-buffer-copy, basic-save-buffer-2): Take care against
writing thru an unexpected existing symlink.
(revert-buffer): In indirect buffer, revert the base buffer.
(magic-mode-alist): Doc fix.
(buffer-stale-function): Doc fix.
(minibuffer-with-setup-hook): Avoid warning.
(mode-require-final-newline): Doc and custom fix.

1 files changed, 167 insertions, 143 deletions

diff --git a/lisp/files.el b/lisp/files.el
index 407922082f1..1186a5fb8b4 100644
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -300,16 +300,15 @@ A value of t means do this only when the file is about to be saved.
 A value of `visit' means do this right after the file is visited.
 A value of `visit-save' means do it at both of those times.
 Any other non-nil value means ask user whether to add a newline, when saving.
-nil means don't add newlines.
+nil means do not add newlines when saving.
 
-You will have to be careful if you set this to nil: you will have
-to remember to manually add a final newline whenever you finish a
-file that really needs one."
+If you set this to nil, you must careful to manually add a final newline
+whenever you save a file that really needs one."
   :type '(choice (const :tag "When visiting" visit)
                  (const :tag "When saving" t)
                  (const :tag "When visiting or saving" visit-save)
-                 (const :tag "Never" nil)
-                 (other :tag "Ask" ask))
+                 (other :tag "Ask" ask)
+                 (const :tag "Don't add newlines" nil))
   :group 'editing-basics
   :version "22.1")
 
@@ -529,8 +528,8 @@ See Info node `(elisp)Standard File Names' for more details."
 Value is not expanded---you must call `expand-file-name' yourself.
 Default name to DEFAULT-DIRNAME if user exits with the same
 non-empty string that was inserted by this function.
- (If DEFAULT-DIRNAME is omitted, the current buffer's directory is used,
-  except that if INITIAL is specified, that combined with DIR is used.)
+ (If DEFAULT-DIRNAME is omitted, DIR combined with INITIAL is used,
+  or just DIR if INITIAL is nil.)
 If the user exits with an empty minibuffer, this function returns
 an empty string.  (This can only happen if the user erased the
 pre-inserted contents or if `insert-default-directory' is nil.)
@@ -544,7 +543,10 @@ the value of `default-directory'."
   (unless default-dirname
     (setq default-dirname
           (if initial (concat dir initial) default-directory)))
-  (read-file-name prompt dir default-dirname mustmatch initial
+  (read-file-name prompt dir (or default-dirname 
+                                 (if initial (expand-file-name initial dir)
+                                   dir))
+                  mustmatch initial
                   'file-directory-p))
 
 
@@ -940,12 +942,13 @@ BODY should use the minibuffer at most once.
 Recursive uses of the minibuffer will not be affected."
   (declare (indent 1) (debug t))
   (let ((hook (make-symbol "setup-hook")))
-    `(let ((,hook
-            (lambda ()
-              ;; Clear out this hook so it does not interfere
-              ;; with any recursive minibuffer usage.
-              (remove-hook 'minibuffer-setup-hook ,hook)
-              (,fun))))
+    `(let (,hook)
+       (setq ,hook
+             (lambda ()
+               ;; Clear out this hook so it does not interfere
+               ;; with any recursive minibuffer usage.
+               (remove-hook 'minibuffer-setup-hook ,hook)
+               (,fun)))
        (unwind-protect
            (progn
              (add-hook 'minibuffer-setup-hook ,hook)
@@ -1973,8 +1976,13 @@ with that interpreter in `interpreter-mode-alist'.")
     ("%![^V]" . ps-mode)
     ("# xmcd " . conf-unix-mode))
   "Alist of buffer beginnings vs. corresponding major mode functions.
-Each element looks like (REGEXP . FUNCTION).  FUNCTION will be
-called, unless it is nil (to allow `auto-mode-alist' to override).")
+Each element looks like (REGEXP . FUNCTION).  After visiting a file,
+if REGEXP matches the text at the beginning of the buffer,
+`normal-mode' will call FUNCTION rather than allowing `auto-mode-alist'
+to decide the buffer's major mode.
+
+If FUNCTION is nil, then it is not called.  (That is a way of saying
+\"allow `auto-mode-alist' to decide for these files.")
 
 (defun set-auto-mode (&optional keep-mode-if-same)
   "Select major mode appropriate for current buffer.
@@ -2740,15 +2748,27 @@ BACKUPNAME is the backup file name, which is the old file renamed."
             (file-error nil))))))
 
 (defun backup-buffer-copy (from-name to-name modes)
-  (condition-case ()
-      (copy-file from-name to-name t t)
-    (file-error
-     ;; If copying fails because file TO-NAME
-     ;; is not writable, delete that file and try again.
-     (if (and (file-exists-p to-name)
-              (not (file-writable-p to-name)))
-         (delete-file to-name))
-     (copy-file from-name to-name t t)))
+  (let ((umask (default-file-modes)))
+    (unwind-protect
+        (progn
+          ;; Create temp files with strict access rights.  It's easy to
+          ;; loosen them later, whereas it's impossible to close the
+          ;; time-window of loose permissions otherwise.
+          (set-default-file-modes ?\700)
+          (while (condition-case ()
+                     (progn
+                       (condition-case nil
+                           (delete-file to-name)
+                         (file-error nil))
+                       (write-region "" nil to-name nil 'silent nil 'excl)
+                       nil)
+                   (file-already-exists t))
+            ;; the file was somehow created by someone else between
+            ;; `make-temp-name' and `write-region', let's try again.
+            nil)
+          (copy-file from-name to-name t t 'excl))
+      ;; Reset the umask.
+      (set-default-file-modes umask)))
   (and modes
        (set-file-modes to-name (logand modes #o1777))))
 
@@ -3331,39 +3351,41 @@ Before and after saving the buffer, this function runs
           ;; This requires write access to the containing dir,
           ;; which is why we don't try it if we don't have that access.
           (let ((realname buffer-file-name)
-                tempname nogood i succeed
+                tempname succeed
+                (umask (default-file-modes))
                 (old-modtime (visited-file-modtime)))
-            (setq i 0)
-            (setq nogood t)
-            ;; Find the temporary name to write under.
-            (while nogood
-              (setq tempname (format
-                              (if (and (eq system-type 'ms-dos)
-                                       (not (msdos-long-file-names)))
-                                  "%s#%d.tm#" ; MSDOS limits files to 8+3
-                                (if (memq system-type '(vax-vms axp-vms))
-                                    "%s$tmp$%d"
-                                  "%s#tmp#%d"))
-                              dir i))
-              (setq nogood (file-exists-p tempname))
-              (setq i (1+ i)))
+            ;; Create temp files with strict access rights.  It's easy to
+            ;; loosen them later, whereas it's impossible to close the
+            ;; time-window of loose permissions otherwise.
             (unwind-protect
-                (progn (clear-visited-file-modtime)
-                       (write-region (point-min) (point-max)
-                                     tempname nil realname
-                                     buffer-file-truename)
-                       (setq succeed t))
-              ;; If writing the temp file fails,
-              ;; delete the temp file.
-              (or succeed
-                  (progn
-                    (condition-case nil
-                        (delete-file tempname)
-                      (file-error nil))
-                    (set-visited-file-modtime old-modtime))))
-            ;; Since we have created an entirely new file
-            ;; and renamed it, make sure it gets the
-            ;; right permission bits set.
+                (progn
+                  (clear-visited-file-modtime)
+                  (set-default-file-modes ?\700)
+                  ;; Try various temporary names.
+                  ;; This code follows the example of make-temp-file,
+                  ;; but it calls write-region in the appropriate way
+                  ;; for saving the buffer.
+                  (while (condition-case ()
+                             (progn
+                               (setq tempname
+                                     (make-temp-name
+                                      (expand-file-name "tmp" dir)))
+                               (write-region (point-min) (point-max)
+                                             tempname nil  realname
+                                             buffer-file-truename 'excl)
+                               nil)
+                           (file-already-exists t))
+                    ;; The file was somehow created by someone else between
+                    ;; `make-temp-name' and `write-region', let's try again.
+                    nil)
+                  (setq succeed t))
+              ;; Reset the umask.
+              (set-default-file-modes umask)
+              ;; If we failed, restore the buffer's modtime.
+              (unless succeed
+                (set-visited-file-modtime old-modtime)))
+            ;; Since we have created an entirely new file,
+            ;; make sure it gets the right permission bits set.
             (setq setmodes (or setmodes (cons (file-modes buffer-file-name)
                                               buffer-file-name)))
             ;; We succeeded in writing the temp file,
@@ -3649,7 +3671,7 @@ The function you specify is responsible for updating (or preserving) point.")
 (defvar buffer-stale-function nil
   "Function to check whether a non-file buffer needs reverting.
 This should be a function with one optional argument NOCONFIRM.
-Auto Revert Mode sets NOCONFIRM to t.  The function should return
+Auto Revert Mode passes t for NOCONFIRM.  The function should return
 non-nil if the buffer should be reverted.  A return value of
 `fast' means that the need for reverting was not checked, but
 that reverting the buffer is fast.  The buffer is current when
@@ -3718,91 +3740,93 @@ non-nil, it is called instead of rereading visited file contents."
   (interactive (list (not current-prefix-arg)))
   (if revert-buffer-function
       (funcall revert-buffer-function ignore-auto noconfirm)
-    (let* ((auto-save-p (and (not ignore-auto)
-                             (recent-auto-save-p)
-                             buffer-auto-save-file-name
-                             (file-readable-p buffer-auto-save-file-name)
-                             (y-or-n-p
-   "Buffer has been auto-saved recently.  Revert from auto-save file? ")))
-           (file-name (if auto-save-p
-                          buffer-auto-save-file-name
-                        buffer-file-name)))
-      (cond ((null file-name)
-             (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)
-             ;; If file was backed up but has changed since,
-             ;; we shd make another backup.
-             (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
-                     (abbreviate-file-name (file-truename buffer-file-name)))
-               (after-find-file nil nil t t preserve-modes)
-               ;; Run after-revert-hook as it was before we reverted.
-               (setq-default revert-buffer-internal-hook global-hook)
-               (if local-hook-p
-                   (set (make-local-variable 'revert-buffer-internal-hook)
-                        local-hook)
-                 (kill-local-variable 'revert-buffer-internal-hook))
-               (run-hooks 'revert-buffer-internal-hook))
-             t)))))
+    (with-current-buffer (or (buffer-base-buffer (current-buffer))
+                             (current-buffer))
+      (let* ((auto-save-p (and (not ignore-auto)
+                               (recent-auto-save-p)
+                               buffer-auto-save-file-name
+                               (file-readable-p buffer-auto-save-file-name)
+                               (y-or-n-p
+     "Buffer has been auto-saved recently.  Revert from auto-save file? ")))
+             (file-name (if auto-save-p
+                            buffer-auto-save-file-name
+                          buffer-file-name)))
+        (cond ((null file-name)
+               (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)
+               ;; If file was backed up but has changed since,
+               ;; we shd make another backup.
+               (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
+                       (abbreviate-file-name (file-truename buffer-file-name)))
+                 (after-find-file nil nil t t preserve-modes)
+                 ;; Run after-revert-hook as it was before we reverted.
+                 (setq-default revert-buffer-internal-hook global-hook)
+                 (if local-hook-p
+                     (set (make-local-variable 'revert-buffer-internal-hook)
+                          local-hook)
+                   (kill-local-variable 'revert-buffer-internal-hook))
+                 (run-hooks 'revert-buffer-internal-hook))
+               t))))))
 
 (defun recover-this-file ()
   "Recover the visited file--get contents from its last auto-save file."