[Emacs-diffs] /srv/bzr/emacs/trunk r103413: Partial fix for bug#8095.

[Glenn Morris]

------------------------------------------------------------
revno: 103413
committer: Glenn Morris <address@hidden>
branch nick: trunk
timestamp: Wed 2011-02-23 23:47:06 -0800
message:
  Partial fix for bug#8095.
  
  * lisp/files.el (dir-locals-find-file): Doc fix.
  Fix the check for cache elements that have no associated file,
  and the mtime check for those that do.
  
  Still to do: some places that use dir-locals-find-file assume the
  result is always a file, which is not true. (The function name is
  misleading.)
modified:
  lisp/ChangeLog
  lisp/files.el

=== modified file 'lisp/ChangeLog'
--- a/lisp/ChangeLog    2011-02-24 03:59:04 +0000
+++ b/lisp/ChangeLog    2011-02-24 07:47:06 +0000
@@ -1,5 +1,9 @@
 2011-02-24  Glenn Morris  <address@hidden>
 
+       * files.el (dir-locals-find-file): Doc fix.
+       Fix the check for cache elements that have no associated file,
+       and the mtime check for those that do.
+
        * dired-x.el (dired-hack-local-variables):
        Handle interrupts during hacking local variables.  (Bug#5216)
 

=== modified file 'lisp/files.el'
--- a/lisp/files.el     2011-02-23 03:24:23 +0000
+++ b/lisp/files.el     2011-02-24 07:47:06 +0000
@@ -3347,11 +3347,11 @@
 DIR is the name of the directory.
 CLASS is the name of a variable class (a symbol).
 MTIME is the recorded modification time of the directory-local
- variables file associated with this entry.  This time is a list
- of two integers (the same format as `file-attributes'), and is
- used to test whether the cache entry is still valid.
- Alternatively, MTIME can be nil, which means the entry is always
- considered valid.")
+variables file associated with this entry.  This time is a list
+of two integers (the same format as `file-attributes'), and is
+used to test whether the cache entry is still valid.
+Alternatively, MTIME can be nil, which means the entry is always
+considered valid.")
 
 (defsubst dir-locals-get-class-variables (class)
   "Return the variable list for CLASS."
@@ -3460,13 +3460,20 @@
 (defun dir-locals-find-file (file)
   "Find the directory-local variables for FILE.
 This searches upward in the directory tree from FILE.
-If the directory root of FILE has been registered in
- `dir-locals-directory-cache' and the directory-local variables
- file has not been modified, return the matching entry in
- `dir-locals-directory-cache'.
-Otherwise, if a directory-local variables file is found, return
- the file name.
-Otherwise, return nil."
+It stops at the first directory that has been registered in
+`dir-locals-directory-cache' or contains a `dir-locals-file'.
+If it finds an entry in the cache, it checks that it is valid.
+A cache entry with no modification time element (normally, one that
+has been assigned directly using `dir-locals-set-directory-class', not
+set from a file) is always valid.
+A cache entry based on a `dir-locals-file' is valid if the modification
+time stored in the cache matches the current file modification time.
+If not, the cache entry is cleared so that the file will be re-read.
+
+This function returns either nil (no directory local variables found),
+or the matching entry from `dir-locals-directory-cache' (a list),
+or the full path to the `dir-locals-file' (a string) in the case
+of no valid cache entry."
   (setq file (expand-file-name file))
   (let* ((dir-locals-file-name
          (if (eq system-type 'ms-dos)
@@ -3475,8 +3482,8 @@
         (locals-file (locate-dominating-file file dir-locals-file-name))
         (dir-elt nil))
     ;; `locate-dominating-file' may have abbreviated the name.
-    (when locals-file
-      (setq locals-file (expand-file-name dir-locals-file-name locals-file)))
+    (if locals-file
+       (setq locals-file (expand-file-name dir-locals-file-name locals-file)))
     ;; Find the best cached value in `dir-locals-directory-cache'.
     (dolist (elt dir-locals-directory-cache)
       (when (and (eq t (compare-strings file nil (length (car elt))
@@ -3485,23 +3492,32 @@
                                              '(windows-nt cygwin ms-dos))))
                 (> (length (car elt)) (length (car dir-elt))))
        (setq dir-elt elt)))
-    (let ((use-cache (and dir-elt
-                         (or (null locals-file)
-                             (<= (length (file-name-directory locals-file))
-                                 (length (car dir-elt)))))))
-      (if use-cache
-         ;; Check the validity of the cache.
-         (if (and (file-readable-p (car dir-elt))
-                  (or (null  (nth 2 dir-elt))
+    (if (and dir-elt
+            (or (null locals-file)
+                (<= (length (file-name-directory locals-file))
+                    (length (car dir-elt)))))
+       ;; Found a potential cache entry.  Check validity.
+       ;; A cache entry with no MTIME is assumed to always be valid
+       ;; (ie, set directly, not from a dir-locals file).
+       ;; Note, we don't bother to check that there is a matching class
+       ;; element in dir-locals-class-alist, since that's done by
+       ;; dir-locals-set-directory-class.
+       (if (or (null (nth 2 dir-elt))
+               (let ((cached-file (expand-file-name dir-locals-file-name
+                                                    (car dir-elt))))
+                 (and (file-readable-p cached-file)
                       (equal (nth 2 dir-elt)
-                             (nth 5 (file-attributes (car dir-elt))))))
-             ;; This cache entry is OK.
-             dir-elt
-           ;; This cache entry is invalid; clear it.
-           (setq dir-locals-directory-cache
-                 (delq dir-elt dir-locals-directory-cache))
-           locals-file)
-       locals-file))))
+                             (nth 5 (file-attributes cached-file))))))
+           ;; This cache entry is OK.
+           dir-elt
+         ;; This cache entry is invalid; clear it.
+         (setq dir-locals-directory-cache
+               (delq dir-elt dir-locals-directory-cache))
+         ;; Return the first existing dir-locals file.  Might be the same
+         ;; as dir-elt's, might not (eg latter might have been deleted).
+         locals-file)
+      ;; No cache entry.
+      locals-file)))
 
 (defun dir-locals-read-from-file (file)
   "Load a variables FILE and register a new class and instance.
@@ -3531,6 +3547,7 @@
          (dir-name nil))
       (cond
        ((stringp variables-file)
+       ;; FIXME seems like the wrong dir-name.
        (setq dir-name (if (buffer-file-name)
                            (file-name-directory (buffer-file-name))
                          default-directory))