From c7e05efb767e7bf6f2738ab452f54442c0ccb3bb Mon Sep 17 00:00:00 2001
From: Christian Brabandt <cb@256bit.org>
Date: Fri, 11 May 2018 09:50:13 +0200
Subject: [PATCH] Only consider regular files for the '[noperm]'

Recently, NERDTree added the &readonly setting to its buffer.
Unfortunately, this caused airline to render the '[noperm]' string in
it.

Fix this by only making the readonly check for buffers that actually
represent files (e.g. the buftype option is empty).
---
 autoload/airline/parts.vim | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/autoload/airline/parts.vim b/autoload/airline/parts.vim
index da7eef6..e6146ce 100644
--- a/autoload/airline/parts.vim
+++ b/autoload/airline/parts.vim
@@ -86,6 +86,11 @@ function! airline#parts#iminsert()
 endfunction
 
 function! airline#parts#readonly()
+  " only consider regular buffers (e.g. ones that represent actual files, 
+  " but not special ones like e.g. NERDTree)
+  if !empty(&buftype)
+    return ''
+  endif
   if &readonly && !filereadable(bufname('%'))
     return '[noperm]'
   else