bug#17330: files.el cd-absolute overcome false negative from file-executable-p

[Stefan Monnier]

> After discovering that even C functions can be redefined, today I "activated
> an advice" so that all file-executable-p C code calls from Lisp return t.
> No unexpected refusals, no noticeable downsides, no waiting months for
> C code changes to appear in a new official release.

The changes being discussed are to `cd-absolute' which is an Elisp
function, so no need for recompilation.

E.g. if you add

   (defun cd-absolute (dir)
     "Change current directory to given absolute file name DIR."
     ;; Put the name into directory syntax now,
     ;; because otherwise expand-file-name may give some bad results.
     (setq dir (file-name-as-directory dir))
     ;; We used to additionally call abbreviate-file-name here, for an
     ;; unknown reason.  Problem is that most buffers are setup
     ;; without going through cd-absolute and don't call
     ;; abbreviate-file-name on their default-directory, so the few that
     ;; do end up using a superficially different directory.
     (setq dir (expand-file-name dir))
     (if (not (file-directory-p dir))
         (if (file-exists-p dir)
          (error "%s is not a directory" dir)
        (error "%s: no such directory" dir))
       (unless (file-accessible-directory-p dir)
         (error "Cannot cd to %s:  Permission denied" dir))
       (setq default-directory dir)
       (setq list-buffers-directory dir)))

to your .emacs, does it fix the problem for you?


        Stefan