Revert all recent changes about emacs-helm#2668

Author: thierryvolpiatto

helm-files.el

@@ -850,27 +850,13 @@ directories belonging to each visible windows."
                  nil)))
 
 (defcustom helm-ff-use-notify t
-  "Control watching and caching directories visited with `helm-find-files'.
-
-When `t' watch and cache directories.
-When `nil' stop watching directories but continue caching directories.
-Any other value disable watching directories and disable caching as well.
-
+  "Watch directories visited with `helm-find-files' when non nil.
 If your system have no file notification package available turn this
-to nil or 0 to avoid error messages when using `helm-find-files'.
-
-You can also disable watching and caching in specific tramp methods by settings
-`helm-ff-incompatible-notify-methods', in this case no need to modify default
-setting of `helm-ff-use-notify'.
-
-Warning: Do not use `setq' to set this variable."
-  :type '(radio
-          (const :tag "Enable watching and caching directories" t)
-          (const :tag "Disable watching only" nil)
-          (const :tag "Disable watching and caching" 0))
+to nil to avoid error messages when using `helm-find-files'."
+  :type 'boolean
   :set (lambda (var val)
 	 (set-default var val)
-	 (unless (eq (symbol-value var) t)
+	 (unless (symbol-value var)
            (cl-loop for dir being the hash-keys of helm-ff--file-notify-watchers
                     do (remhash dir helm-ff--list-directory-cache)))))
 
@@ -3802,11 +3788,6 @@ later in the transformer."
 ;; watcher ring on the truename remove the symlinked directory from cache.  
 (defvar helm-ff--list-directory-links nil)
 
-(defvar helm-ff-incompatible-notify-methods nil
-  "Tramp methods incompatible with (i)notify.
-When `helm-find-files' visit a directory with one of those methods, it stops
-using the cache and setting a watcher in this directory.")
-
 (defun helm-ff-directory-files (directory &optional force-update)
   "List contents of DIRECTORY.
 Argument FULL mean absolute path.
@@ -3817,17 +3798,13 @@ When FORCE-UPDATE is non nil recompute candidates even if DIRECTORY is
 in cache."
   (let* ((method (file-remote-p directory 'method))
          (dfn (directory-file-name directory))
-         (truename (and (file-symlink-p dfn) (file-truename dfn)))
-         (tramp-compatible (not (member (file-remote-p directory 'method)
-                                        helm-ff-incompatible-notify-methods))))
+         (truename (and (file-symlink-p dfn) (file-truename dfn))))
     (setq directory (file-name-as-directory
                      (expand-file-name directory)))
     (when truename
       (cl-pushnew (cons truename directory)
                   helm-ff--list-directory-links :test 'equal))
     (or (and (not force-update)
-             (booleanp helm-ff-use-notify)
-             tramp-compatible
              (gethash directory helm-ff--list-directory-cache))
         (let* (file-error
                (ls   (condition-case err
@@ -3852,16 +3829,13 @@ in cache."
                watcher)
           (puthash directory (+ (length ls) 2) helm-ff--directory-files-length)
           (prog1
-              (let ((lst (cl-loop for f in candidates
-                                  when (helm-ff-filter-candidate-one-by-one f)
-                                  collect it)))
-                (if tramp-compatible
-                    (puthash directory lst helm-ff--list-directory-cache)
-                  lst))
+              (puthash directory
+                       (cl-loop for f in candidates
+                                when (helm-ff-filter-candidate-one-by-one f)
+                                collect it)
+                       helm-ff--list-directory-cache)
             ;; Put an inotify watcher to check directory modifications.
             (unless (or (null helm-ff-use-notify)
-                        (not (booleanp helm-ff-use-notify))
-                        (not tramp-compatible)
                         (member method helm-ff-inotify-unsupported-methods)
                         (helm-aand (setq watcher (gethash
                                                   directory