Index: lisp/files.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/files.el,v
retrieving revision 1.1005
diff -U 8 -r1.1005 files.el
--- lisp/files.el	18 Oct 2008 18:40:25 -0000	1.1005
+++ lisp/files.el	24 Oct 2008 23:37:19 -0000
@@ -711,18 +711,59 @@
 (defun locate-file-completion (string path-and-suffixes action)
   "Do completion for file names passed to `locate-file'.
 PATH-AND-SUFFIXES is a pair of lists, (DIRECTORIES . SUFFIXES)."
   (locate-file-completion-table (car path-and-suffixes)
                                 (cdr path-and-suffixes)
                                 string nil action))
 (make-obsolete 'locate-file-completion 'locate-file-completion-table "23.1")
 
-(defun locate-dominating-file (file regexp)
-  "Look up the directory hierarchy from FILE for a file matching REGEXP."
+(defun locate-dominating-file (file name)
+   "Look up the directory hierarchy from FILE for a file named NAME.
+If found, return the file named NAME's full name and path, otherwise
+return nil. See locate-dominating-file-by-regexp if you have more
+complex requirements than a simple whole-string match on the name,
+though beware it is slower."
+   ;; copied from vc-find-root, then changed to return file
+   ;; rather than containing dir.
+   ;; Represent /home/luser/foo as ~/foo so that we don't try to look for
+   ;; witnesses in /home or in /.
+   (setq file (abbreviate-file-name file))
+   (let ((root nil)
+	 (prev-file file)
+	 ;; `user' is not initialized outside the loop because
+	 ;; `file' may not exist, so we may have to walk up part of the
+	 ;; hierarchy before we find the "initial UID".
+	 (user nil)
+	 try)
+     (while (not (or root
+		     (null file)
+		     ;; As a heuristic, we stop looking up the hierarchy of
+		     ;; directories as soon as we find a directory belonging
+		     ;; to another user.  This should save us from looking in
+		     ;; things like /net and /afs.  This assumes that all the
+		     ;; files inside a project belong to the same user.
+		     (let ((prev-user user))
+		       (setq user (nth 2 (file-attributes file)))
+		       (and prev-user (not (equal user prev-user))))
+		     (string-match
+		      ;; from vc-ignore-dir-regexp !
+		      "\\`\\(?:[\\/][\\/]\\|/\\(?:net\\|afs\\|\\.\\.\\.\\)/\\)\\'"
+		      file)))
+       (setq try (file-exists-p (expand-file-name name file)))
+       (cond (try (setq root file))
+	     ((equal file (setq prev-file file
+				file (file-name-directory
+				      (directory-file-name file))))
+	      (setq file nil))))
+     (when root (expand-file-name name root))))
+
+(defun locate-dominating-file-by-regexp (file regexp)
+  "Look up the directory hierarchy from FILE for a file matching REGEXP.
+This function is slower than `locate-dominating-file', only use if necessary."
   (catch 'found
     ;; `user' is not initialized yet because `file' may not exist, so we may
     ;; have to walk up part of the hierarchy before we find the "initial UID".
     (let ((user nil)
           ;; Abbreviate, so as to stop when we cross ~/.
           (dir (abbreviate-file-name (file-name-as-directory file)))
           files)
       (while (and dir
@@ -3154,17 +3195,17 @@
 (defun project-find-settings-file (file)
   "Find the settings file for FILE.
 This searches upward in the directory tree.
 If a settings file is found, the file name is returned.
 If the file is in a registered project, a cons from
 `project-directory-alist' is returned.
 Otherwise this returns nil."
   (setq file (expand-file-name file))
-  (let* ((settings (locate-dominating-file file "\\`\\.dir-settings\\.el\\'"))
+  (let* ((settings (locate-dominating-file file ".dir-settings.el"))
          (pda nil))
     ;; `locate-dominating-file' may have abbreviated the name.
     (if settings (setq settings (expand-file-name settings)))
     (dolist (x project-directory-alist)
       (when (and (eq t (compare-strings file nil (length (car x))
                                         (car x) nil nil))
                  (> (length (car x)) (length (car pda))))
         (setq pda x)))