Fix argument of exists() function calls checking for autocommands. (#1165)

* Fix syntax of exists function calls checking for autocommands.

* Update version number in change log.

CHANGELOG.md

@@ -5,6 +5,8 @@
         - **.PATCH**: Pull Request Title (PR Author) [PR Number](Link to PR)
 -->
 #### 6.9
+- **.7**: Fix argument of `exists()` function calls checking for autocommands. (PhilRunninger) [#1165](https://github.com/preservim/nerdtree/pull/1165)
+- **.6**: Don't use silent when raising User events (PhilRunninger) [#1164](https://github.com/preservim/nerdtree/pull/1164)
 - **.5**: Fix highlight for file node.  (pirey) [#1157](https://github.com/preservim/nerdtree/pull/1157)
 - **.4**: Make sure symbolic links' flags are highlighted correctly.  (PhilRunninger) [#1156](https://github.com/preservim/nerdtree/pull/1156)
 - **.3**: Fix new NERDTrees' width when previous one was in the only window. (PhilRunninger) [#1153](https://github.com/preservim/nerdtree/pull/1153)

lib/nerdtree/creator.vim

@@ -28,7 +28,9 @@ endfunction
 
 " FUNCTION: s:Creator._broadcastInitEvent() {{{1
 function! s:Creator._broadcastInitEvent()
-    silent doautocmd User NERDTreeInit
+    if exists('#User#NERDTreeInit')
+        doautocmd User NERDTreeInit
+    endif
 endfunction
 
 " FUNCTION: s:Creator.BufNamePrefix() {{{1

lib/nerdtree/nerdtree.vim

@@ -27,7 +27,9 @@ function! s:NERDTree.changeRoot(node)
     call self.render()
     call self.root.putCursorHere(0, 0)
 
-    silent doautocmd User NERDTreeNewRoot
+    if exists('#User#NERDTreeNewRoot')
+        doautocmd User NERDTreeNewRoot
+    endif
 endfunction
 
 "FUNCTION: s:NERDTree.Close() {{{1