patch 9.0.2030: no max callback recursion limit

Problem:  no max callback recursion limit
Solution: bail out, if max call recursion for callback functions
          has been reached.

This checks the 'maxfuncdepth' setting and throws E169 when a callback
function recursively calls itself.

closes: #13337
closes: #13339

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/testdir/test_popupwin.vim b/src/testdir/test_popupwin.vim
index 60dc5d9..a256ddf 100644
--- a/src/testdir/test_popupwin.vim
+++ b/src/testdir/test_popupwin.vim
@@ -4205,5 +4205,11 @@
   call StopVimInTerminal(buf)
 endfunc
 
+func Test_popup_close_callback_recursive()
+  " this invokes the callback recursively
+  let winid = popup_create('something', #{callback: 'popup_close'})
+  redraw
+  call assert_fails('call popup_close(winid)', 'E169')
+endfunc
 
 " vim: shiftwidth=2 sts=2