From b6e83ba28469345ee145ab6da2c4ef7f3285d726 Mon Sep 17 00:00:00 2001
From: Jan Edmund Lazo <janedmundlazo@hotmail.com>
Date: Mon, 3 Sep 2018 21:06:59 -0400
Subject: [PATCH] vim-patch:8.1.0334: 'autowrite' takes effect when buffer is
 not to be written

Problem:    'autowrite' takes effect when buffer is not to be written.
Solution:   Don't write buffers that are not supposed to be written. (Even Q
            Jones, closes vim/vim#3391)  Add tests for 'autowrite'.
https://github.com/vim/vim/commit/8c9e7b00f6566dc41e794ef11c93d93b034c7134
---
 src/nvim/ex_cmds2.c                 |  4 +--
 src/nvim/testdir/test_writefile.vim | 38 +++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/src/nvim/ex_cmds2.c b/src/nvim/ex_cmds2.c
index f5822535ba..6e695a8897 100644
--- a/src/nvim/ex_cmds2.c
+++ b/src/nvim/ex_cmds2.c
@@ -1209,7 +1209,7 @@ int autowrite(buf_T *buf, int forceit)
   return r;
 }
 
-/// flush all buffers, except the ones that are readonly
+/// Flush all buffers, except the ones that are readonly or are never written.
 void autowrite_all(void)
 {
   if (!(p_aw || p_awa) || !p_write) {
@@ -1217,7 +1217,7 @@ void autowrite_all(void)
   }
 
   FOR_ALL_BUFFERS(buf) {
-    if (bufIsChanged(buf) && !buf->b_p_ro) {
+    if (bufIsChanged(buf) && !buf->b_p_ro && !bt_dontwrite(buf)) {
       bufref_T bufref;
       set_bufref(&bufref, buf);
       (void)buf_write_all(buf, false);
diff --git a/src/nvim/testdir/test_writefile.vim b/src/nvim/testdir/test_writefile.vim
index f297f8eb2f..06f9d03554 100644
--- a/src/nvim/testdir/test_writefile.vim
+++ b/src/nvim/testdir/test_writefile.vim
@@ -75,3 +75,41 @@ func Test_nowrite_quit_split()
   endif
   bwipe Xfile
 endfunc
+
+func Test_writefile_autowrite()
+  set autowrite
+  new
+  next Xa Xb Xc
+  call setline(1, 'aaa')
+  next
+  call assert_equal(['aaa'], readfile('Xa'))
+  call setline(1, 'bbb')
+  call assert_fails('edit XX')
+  call assert_false(filereadable('Xb'))
+
+  set autowriteall
+  edit XX
+  call assert_equal(['bbb'], readfile('Xb'))
+
+  bwipe!
+  call delete('Xa')
+  call delete('Xb')
+  set noautowrite
+endfunc
+
+func Test_writefile_autowrite_nowrite()
+  set autowrite
+  new
+  next Xa Xb Xc
+  set buftype=nowrite
+  call setline(1, 'aaa')
+  let buf = bufnr('%')
+  " buffer contents silently lost
+  edit XX
+  call assert_false(filereadable('Xa'))
+  rewind
+  call assert_equal('', getline(1))
+
+  bwipe!
+  set noautowrite
+endfunc