(file-truename): Don't use expand-file-name to merge

a link target into the previous dir.  Handle .. and . explicitly.

diff --git a/lisp/files.el b/lisp/files.el
index c31b75e1ce6881f82ce7f35620cb94370d11b77a..96cc510a61c2112858fd947b0acceb8aa4446722 100644 (file)
--- a/lisp/files.el
+++ b/lisp/files.el
@@ -329,16 +329,25 @@ containing it, until no links are left at any level."
        ;; If these are equal, we have the (or a) root directory.
        (or (string= dir dirfile)
            (setq dir (file-name-as-directory (file-truename dirfile))))
-       ;; Put it back on the file name.
-       (setq filename (concat dir (file-name-nondirectory filename)))
-       ;; Is the file name the name of a link?
-       (setq target (file-symlink-p filename))
-       (if target
-           ;; Yes => chase that link, then start all over
-           ;; since the link may point to a directory name that uses links.
-           (file-truename (expand-file-name target dir))
-         ;; No, we are done!
-         filename)))))
+       (if (equal ".." (file-name-nondirectory filename))
+           (directory-file-name (file-name-directory (directory-file-name dir)))
+         (if (equal "." (file-name-nondirectory filename))
+             (directory-file-name dir)
+           ;; Put it back on the file name.
+           (setq filename (concat dir (file-name-nondirectory filename)))
+           ;; Is the file name the name of a link?
+           (setq target (file-symlink-p filename))
+           (if target
+               ;; Yes => chase that link, then start all over
+               ;; since the link may point to a directory name that uses links.
+               ;; We can't safely use expand-file-name here
+               ;; since target might look like foo/../bar where foo
+               ;; is itself a link.  Instead, we handle . and .. above.
+               (if (file-name-absolute-p target)
+                   (file-truename target)
+                 (file-truename (concat dir target)))
+             ;; No, we are done!
+             filename)))))))
 
 (defun file-chase-links (filename)
   "Chase links in FILENAME until a name that is not a link.