vim-patch:8.1.2385: open cmdline window with feedkeys() #11516

Problem:    Opening cmdline window with feedkeys() does not work. (Yegappan
            Lakshmanan)
Solution:   Recognize K_CMDWIN also when ex_normal_busy is set.
85db547598

src/nvim/ex_getln.c

@@ -878,7 +878,9 @@ static int command_line_execute(VimState *state, int key)
   }
 
   if (s->c == cedit_key || s->c == K_CMDWIN) {
-    if (ex_normal_busy == 0 && got_int == false) {
+    // TODO(vim): why is ex_normal_busy checked here?
+    if ((s->c == K_CMDWIN || ex_normal_busy == 0)
+        && got_int == false) {
       // Open a window to edit the command line (and history).
       s->c = open_cmdwin();
       s->some_key_typed = true;

src/nvim/testdir/test_cmdline.vim

@@ -750,3 +750,8 @@ func Test_cmdline_overstrike()
 
   let &encoding = encoding_save
 endfunc
+
+func Test_cmdwin_feedkeys()
+  " This should not generate E488
+  call feedkeys("q:\<CR>", 'x')
+endfunc