bug#13860: 24.2; dir-locals-directory-cache unreliable in one rare case

[Lars Ingebrigtsen <larsi@gnus.org>]

Johan Claesson <johanclaesson@bredband.net> writes:

> I think one way to remedy this would be to explicitly invalidate the
> directory cache every time a .dir-local.el file is modified.  Something
> like the following seem to do the trick:
>
> diff --git a/lisp/files-x.el b/lisp/files-x.el
> index b71e9204f3..6b04518fe4 100644
> --- a/lisp/files-x.el
> +++ b/lisp/files-x.el
> @@ -491,6 +491,13 @@ modify-dir-local-variable
>                 (cons `(,mode . ((,variable . ,value)))
>                       variables))))
>
> +      ;; Invalidate cache (may be needed if this .dir-locals.el file
> +      ;; will be written with the same timestamp as is already present
> +      ;; in the cache, see bug#13860).
> +      (setq dir-locals-directory-cache
> +            (assoc-delete-all (file-name-directory variables-file)
> +                              dir-locals-directory-cache))
> +

Thanks; I think this makes sense, so I've applied it to Emacs 27.

-- 
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