Subject: dir-locals-directory-cache confusion

From: Glenn Morris <[email-masked]>
Date: Tue, 22 Feb 2011 03:31:45 -0500

Package: emacs
Version: 23.2.94

There is some weirdness going on with caching of dir-locals files:

mkdir foo

cat <<EOF > foo/.dir-locals.el
((nil . ((sentence-end-double-space . t))))
EOF

emacs -q foo/.dir-locals.el

C-h v sentence-end-double-space

   This variable is a directory local variable
      from the file "/home/gm/tmp/foo/".
               ^^^^^^^^^^^^^^^^^^^^^^^

That's a directory, not a file. Then do:

M-: (setq dir-locals-directory-cache nil)

and repeat:

C-h v sentence-end-double-space

   This variable is a directory local variable
      from the file "/home/gm/tmp/foo/.dir-locals.el".
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

OK, now it's a directory.

Analysis: dir-locals-find-file is either going to return a file (if it
did not find a matching entry in the cache), or a directory (if it did
find an entry in the cache).

Further comment: This line in dir-locals-find-file

(equal (nth 2 dir-elt)
       (nth 5 (file-attributes (car dir-elt))))

compares the mtime element from the cache with the current mtime of the
*directory*. The mtime element in the cache is set by
dir-locals-read-from-file and is the mtime of the *file*.

So in summary there is some confusion between directory and files that
messes up the caching. The whole thing should be consistent about
whether it wants to refer to directories or files.