From f9e83ad8bda884b3fa8a6e5f615dc6ffffa06379 Mon Sep 17 00:00:00 2001
From: Jason Franklin <j_fra@fastmail.us>
Date: Sun, 6 May 2018 12:19:19 -0400
Subject: [PATCH] Fix a bug with the 'u' mapping

This commit refactors the "nerdtree#ui_glue#UpDir()" function to fix
a bug in the behavior of the 'u' mapping.  To reproduce the bug:

  1. Open a bookmarked directory with 'o'
  2. Press 'u' twice, observing normal behavior
  3. Open the same bookmark again with 'o'
  4. Press 'u' again, observe the new root is closed

The reason for this bug is that the parent node already existed and
was closed by the second 'u' press in step two above.

This commit fixes this bug by being careful to always open the new
root and transplant the child node properly.  Also, the internals of
the function in question were refactored to make use of valuable
NERDTree functions that ultimately help to reduce the amount of code
needed for this operation.
---
 autoload/nerdtree/ui_glue.vim | 55 +++++++++++++++--------------------
 1 file changed, 24 insertions(+), 31 deletions(-)

diff --git a/autoload/nerdtree/ui_glue.vim b/autoload/nerdtree/ui_glue.vim
index 0cc3362..6ba9ee6 100644
--- a/autoload/nerdtree/ui_glue.vim
+++ b/autoload/nerdtree/ui_glue.vim
@@ -29,9 +29,9 @@ function! nerdtree#ui_glue#createDefaultBindings()
 
     call NERDTreeAddKeyMap({ 'key': g:NERDTreeMapOpenRecursively, 'scope': "DirNode", 'callback': s."openNodeRecursively" })
 
-    call NERDTreeAddKeyMap({ 'key': g:NERDTreeMapUpdir, 'scope': "all", 'callback': s."upDirCurrentRootClosed" })
-    call NERDTreeAddKeyMap({ 'key': g:NERDTreeMapUpdirKeepOpen, 'scope': "all", 'callback': s."upDirCurrentRootOpen" })
-    call NERDTreeAddKeyMap({ 'key': g:NERDTreeMapChangeRoot, 'scope': "Node", 'callback': s."chRoot" })
+    call NERDTreeAddKeyMap({ 'key': g:NERDTreeMapUpdir, 'scope': 'all', 'callback': s . 'upDirCurrentRootClosed' })
+    call NERDTreeAddKeyMap({ 'key': g:NERDTreeMapUpdirKeepOpen, 'scope': 'all', 'callback': s . 'upDirCurrentRootOpen' })
+    call NERDTreeAddKeyMap({ 'key': g:NERDTreeMapChangeRoot, 'scope': 'Node', 'callback': s . 'chRoot' })
 
     call NERDTreeAddKeyMap({ 'key': g:NERDTreeMapChdir, 'scope': "Node", 'callback': s."chCwd" })
 
@@ -619,40 +619,33 @@ function! s:toggleZoom()
     call b:NERDTree.ui.toggleZoom()
 endfunction
 
-"FUNCTION: nerdtree#ui_glue#upDir(keepState) {{{1
-"moves the tree up a level
+" FUNCTION: nerdtree#ui_glue#upDir(preserveState) {{{1
+" Move the NERDTree up one level.
 "
-"Args:
-"keepState: 1 if the current root should be left open when the tree is
-"re-rendered
-function! nerdtree#ui_glue#upDir(keepState)
-    let cwd = b:NERDTree.root.path.str({'format': 'UI'})
-    if cwd ==# "/" || cwd =~# '^[^/]..$'
-        call nerdtree#echo("already at top dir")
-    else
-        if !a:keepState
-            call b:NERDTree.root.close()
-        endif
+" Args:
+" preserveState: if 1, the current root is left open when the new tree is
+" rendered; if 0, the current root node is closed
+function! nerdtree#ui_glue#upDir(preserveState)
 
-        let oldRoot = b:NERDTree.root
+    try
+        call b:NERDTree.root.cacheParent()
+    catch /^NERDTree.CannotCacheParentError/
+        call nerdtree#echo('already at root directory')
+        return
+    endtry
 
-        if empty(b:NERDTree.root.parent)
-            let path = b:NERDTree.root.path.getParent()
-            let newRoot = g:NERDTreeDirNode.New(path, b:NERDTree)
-            call newRoot.open()
-            call newRoot.transplantChild(b:NERDTree.root)
-            let b:NERDTree.root = newRoot
-        else
-            let b:NERDTree.root = b:NERDTree.root.parent
-        endif
+    let l:oldRoot = b:NERDTree.root
+    let l:newRoot = b:NERDTree.root.parent
 
-        if g:NERDTreeChDirMode ==# 2
-            call b:NERDTree.root.path.changeToDir()
-        endif
+    call l:newRoot.open()
+    call l:newRoot.transplantChild(l:oldRoot)
 
-        call b:NERDTree.render()
-        call oldRoot.putCursorHere(0, 0)
+    if !a:preserveState
+        call l:oldRoot.close()
     endif
+
+    call b:NERDTree.changeRoot(l:newRoot)
+    call l:oldRoot.putCursorHere(0, 0)
 endfunction
 
 " FUNCTION: s:upDirCurrentRootOpen() {{{1