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>

runtime/doc/options.txt

@@ -1,4 +1,4 @@
-*options.txt*	For Vim version 9.0.  Last change: 2023 Aug 15
+*options.txt*	For Vim version 9.0.  Last change: 2023 Oct 14
 
 
 		  VIM REFERENCE MANUAL	  by Bram Moolenaar
@@ -5485,6 +5485,7 @@ A jump table for the options with a short description can be found at |Q_op|.
 	Increasing this limit above 200 also changes the maximum for Ex
 	command recursion, see |E169|.
 	See also |:function|.
+	Also used for maximum depth of callback functions.
 
 						*'maxmapdepth'* *'mmd'* *E223*
 'maxmapdepth' 'mmd'	number	(default 1000)

src/testdir/test_popupwin.vim

@@ -4205,5 +4205,11 @@ func Test_popupwin_with_error()
   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

src/userfunc.c

@@ -3583,6 +3583,13 @@ call_callback(
 
     if (callback->cb_name == NULL || *callback->cb_name == NUL)
 	return FAIL;
+
+    if (callback_depth > p_mfd)
+    {
+	emsg(_(e_command_too_recursive));
+	return FAIL;
+    }
+
     CLEAR_FIELD(funcexe);
     funcexe.fe_evaluate = TRUE;
     funcexe.fe_partial = callback->cb_partial;

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2030,
 /**/
     2029,
 /**/