From f526c4e652c066807db1d8e99c0d23017c511328 Mon Sep 17 00:00:00 2001
From: Jason Franklin <lifecrisis@users.noreply.github.com>
Date: Sat, 18 Nov 2017 09:51:34 -0500
Subject: [PATCH] Clean up the handler for the "x" mapping (#767)

Previously, pressing "x" on the tree root would result in
unpredictable behavior.  The user would either an receive an error
message or the parent of the tree root (which is not visible) would
be closed.  This commit repairs this problem.

In addition, some code duplication was removed.
---
 autoload/nerdtree/ui_glue.vim | 36 +++++++++++++++++++----------------
 1 file changed, 20 insertions(+), 16 deletions(-)

diff --git a/autoload/nerdtree/ui_glue.vim b/autoload/nerdtree/ui_glue.vim
index f5b4726..7929235 100644
--- a/autoload/nerdtree/ui_glue.vim
+++ b/autoload/nerdtree/ui_glue.vim
@@ -184,24 +184,28 @@ function! s:closeChildren(node)
 endfunction
 
 " FUNCTION: s:closeCurrentDir(node) {{{1
-" closes the parent dir of the current node
+" Close the parent directory of the current node.
 function! s:closeCurrentDir(node)
-    let parent = a:node.parent
-    while g:NERDTreeCascadeOpenSingleChildDir && !parent.isRoot()
-        let childNodes = parent.getVisibleChildren()
-        if len(childNodes) == 1 && childNodes[0].path.isDirectory
-            let parent = parent.parent
-        else
-            break
-        endif
-    endwhile
-    if parent ==# {} || parent.isRoot()
-        call nerdtree#echo("cannot close tree root")
-    else
-        call parent.close()
-        call b:NERDTree.render()
-        call parent.putCursorHere(0, 0)
+
+    if a:node.isRoot()
+        call nerdtree#echo('cannot close parent of tree root')
+        return
     endif
+
+    let l:parent = a:node.parent
+
+    if empty(l:parent) || l:parent.isRoot()
+        call nerdtree#echo('cannot close tree root')
+        return
+    endif
+
+    while l:parent.isCascadable()
+        let l:parent = l:parent.parent
+    endwhile
+
+    call l:parent.close()
+    call b:NERDTree.render()
+    call l:parent.putCursorHere(0, 0)
 endfunction
 
 " FUNCTION: s:closeTreeWindow() {{{1