patch 9.0.0871: using freed memory when clearing augroup at more promptv9.0.0871

Problem:    Using freed memory when clearing augroup at more prompt.
Solution:   Delay clearing augroup until it's safe. (closes #11441)

1 files changed, 22 insertions, 0 deletions

diff --git a/src/testdir/test_autocmd.vim b/src/testdir/test_autocmd.vim
index 04f3e1431c..f2f3725b3d 100644
--- a/src/testdir/test_autocmd.vim
+++ b/src/testdir/test_autocmd.vim
@@ -62,6 +62,7 @@ if has('timers')
     set updatetime=20
     call timer_start(200, 'ExitInsertMode')
     call feedkeys('a', 'x!')
+    sleep 30m
     call assert_equal(1, g:triggered)
     unlet g:triggered
     au! CursorHoldI
@@ -2159,6 +2160,27 @@ func Test_autocmd_user()
   unlet s:res
 endfunc
 
+func Test_autocmd_user_clear_group()
+  CheckRunVimInTerminal
+
+  let lines =<< trim END
+    autocmd! User
+    for i in range(1, 999)
+      exe 'autocmd User ' .. 'Foo' .. i .. ' bar'
+    endfor
+    au CmdlineLeave : call timer_start(0, {-> execute('autocmd! User')})
+  END
+  call writefile(lines, 'XautoUser', 'D')
+  let buf = RunVimInTerminal('-S XautoUser', {'rows': 10})
+
+  " this was using freed memory
+  call term_sendkeys(buf, ":autocmd User\<CR>")
+  call TermWait(buf, 50)
+  call term_sendkeys(buf, "G")
+
+  call StopVimInTerminal(buf)
+endfunc
+
 function s:Before_test_dirchanged()
   augroup test_dirchanged
     autocmd!