From a66b12378b1431f886c9b4235160abb171bcb05a Mon Sep 17 00:00:00 2001
From: zeertzjq <zeertzjq@outlook.com>
Date: Wed, 5 Oct 2022 21:33:08 +0800
Subject: [PATCH] vim-patch:8.2.2463: using :arglocal in an autocommand may use
 freed memory

Problem:    Using :arglocal in an autocommand may use freed memory.
            (houyunsong)
Solution:   Check if the arglist is locked.
https://github.com/vim/vim/commit/6bcb877ec19a647443195a54eeac60cb693fd827
---
 src/nvim/arglist.c                | 6 ++++++
 src/nvim/testdir/test_autocmd.vim | 9 +++++++++
 2 files changed, 15 insertions(+)

diff --git a/src/nvim/arglist.c b/src/nvim/arglist.c
index 4e122f1511..7019a6f461 100644
--- a/src/nvim/arglist.c
+++ b/src/nvim/arglist.c
@@ -490,6 +490,9 @@ void check_arg_idx(win_T *win)
 void ex_args(exarg_T *eap)
 {
   if (eap->cmdidx != CMD_args) {
+    if (check_arglist_locked() == FAIL) {
+      return;
+    }
     alist_unlink(ALIST(curwin));
     if (eap->cmdidx == CMD_argglobal) {
       ALIST(curwin) = &global_alist;
@@ -499,6 +502,9 @@ void ex_args(exarg_T *eap)
   }
 
   if (*eap->arg != NUL) {
+    if (check_arglist_locked() == FAIL) {
+      return;
+    }
     // ":args file ..": define new argument list, handle like ":next"
     // Also for ":argslocal file .." and ":argsglobal file ..".
     ex_next(eap);
diff --git a/src/nvim/testdir/test_autocmd.vim b/src/nvim/testdir/test_autocmd.vim
index 07042eab32..c320d3ca78 100644
--- a/src/nvim/testdir/test_autocmd.vim
+++ b/src/nvim/testdir/test_autocmd.vim
@@ -3010,6 +3010,15 @@ func Test_Visual_doautoall_redraw()
   %bwipe!
 endfunc
 
+" This was using freed memory.
+func Test_BufNew_arglocal()
+  arglocal
+  au BufNew * arglocal
+  call assert_fails('drop xx', 'E1156:')
+
+  au! BufNew
+endfunc
+
 func Test_autocmd_closes_window()
   au BufNew,BufWinLeave * e %e
   file yyy