vim-patch:9.1.2098: Crash with 'wildmenu' when typing Ctrl-Y after Ctrl-A (#37466)

Problem:  Crash with 'wildmenu' when typing Ctrl-Y after Ctrl-A
          (after 9.1.1714) (fizz-is-on-the-way).
Solution: Check if there are matches before applying one (zeertzjq).

closes: vim/vim#19210

https://github.com/vim/vim/commit/311b98d94256038fd2a5a823edcb6ab50d2fc8e8

src/nvim/ex_getln.c

@@ -1387,7 +1387,8 @@ static int command_line_execute(VimState *state, int key)
 
   int wild_type = 0;
   const bool key_is_wc = (s->c == p_wc && KeyTyped) || s->c == p_wcm;
-  if ((cmdline_pum_active() || wild_menu_showing || s->did_wild_list) && !key_is_wc) {
+  if ((cmdline_pum_active() || wild_menu_showing || s->did_wild_list)
+      && !key_is_wc && s->xpc.xp_numfiles > 0) {
     // Ctrl-Y: Accept the current selection and close the popup menu.
     // Ctrl-E: cancel the cmdline popup menu and return the original text.
     if (s->c == Ctrl_E || s->c == Ctrl_Y) {

test/old/testdir/test_cmdline.vim

@@ -166,6 +166,16 @@ func Test_complete_wildmenu()
   call feedkeys(":sign un zz\<Left>\<Left>\<Left>\<Tab>\<Tab>\<C-Y> yy\<C-B>\"\<CR>", 'tx')
   call assert_equal('"sign unplace yy zz', @:)
 
+  " This used to crash
+  call feedkeys(":sign un\<Tab>\<S-Tab>\<C-A>\<C-Y>\<C-B>\"\<CR>", 'tx')
+  " Ctrl-Y is inserted literally like before 9.1.1714
+  call assert_equal("\"sign undefine unplace\<C-Y>", @:)
+  " Also test Ctrl-Y after Ctrl-A with selected item (the result is the same)
+  call feedkeys(":sign un\<Tab>\<C-A>\<C-Y>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"sign undefine unplace\<C-Y>", @:)
+  call feedkeys(":sign un\<Tab>\<Tab>\<C-A>\<C-Y>\<C-B>\"\<CR>", 'tx')
+  call assert_equal("\"sign undefine unplace\<C-Y>", @:)
+
   " cleanup
   %bwipe
   set nowildmenu