Recalculate the node's sortkey every time.

The cached _sortkey wasn't being recalculated after changing the
NERDTreeSortOrder, resulting in incorrect sort orders.

lib/nerdtree/path.vim

@@ -7,10 +7,6 @@
 " ============================================================================
 
 
-" This constant is used throughout this script for sorting purposes.
-let s:NERDTreeSortStarIndex = index(g:NERDTreeSortOrder, '*')
-lockvar s:NERDTreeSortStarIndex
-
 let s:Path = {}
 let g:NERDTreePath = s:Path
 
@@ -374,7 +370,8 @@ function! s:Path.getSortOrderIndex()
         endif
         let i = i + 1
     endwhile
-    return s:NERDTreeSortStarIndex
+
+    return index(g:NERDTreeSortOrder, '*')
 endfunction
 
 " FUNCTION: Path._splitChunks(path) {{{1
@@ -395,7 +392,6 @@ endfunction
 " FUNCTION: Path.getSortKey() {{{1
 " returns a key used in compare function for sorting
 function! s:Path.getSortKey()
-    if !exists("self._sortKey")
         let path = self.getLastPathComponent(1)
         if !g:NERDTreeSortHiddenFirst
             let path = substitute(path, '^[._]', '', '')
@@ -408,7 +404,6 @@ function! s:Path.getSortKey()
         else
             let self._sortKey = [self.getSortOrderIndex()] + self._splitChunks(path)
         endif
-    endif
 
     return self._sortKey
 endfunction

lib/nerdtree/tree_dir_node.vim

@@ -607,6 +607,7 @@ endfunction
 " FUNCTION: TreeDirNode.sortChildren() {{{1
 " Sort "self.children" by alphabetical order and directory priority.
 function! s:TreeDirNode.sortChildren()
+    call AddDefaultGroupToSortOrder()
     let CompareFunc = function("nerdtree#compareNodesBySortKey")
     call sort(self.children, CompareFunc)
 endfunction