vim-patch:8.1.0695: internal error when using :popup

Problem:    Internal error when using :popup.
Solution:   When a menu only exists in Terminal mode give an error. (Naruhiko
            Nishino, closes vim/vim#3765)
f42b45d719

runtime/doc/gui.txt

@@ -508,7 +508,9 @@ may be used to complete the name of the menu item for the appropriate mode.
 To remove all menus use:			*:unmenu-all*  >
 	:unmenu *	" remove all menus in Normal and visual mode
 	:unmenu! *	" remove all menus in Insert and Command-line mode
-	:aunmenu *	" remove all menus in all modes
+	:aunmenu *	" remove all menus in all modes, except for Terminal
+			" mode
+	:tlunmenu *	" remove all menus in Terminal mode
 
 If you want to get rid of the menu bar: >
 	:set guioptions-=m

src/nvim/globals.h

@@ -986,6 +986,7 @@ EXTERN char e_notset[] INIT(= N_("E764: Option '%s' is not set"));
 EXTERN char e_invalidreg[] INIT(= N_("E850: Invalid register name"));
 EXTERN char e_dirnotf[] INIT(= N_("E919: Directory not found in '%s': \"%s\""));
 EXTERN char e_au_recursive[] INIT(= N_("E952: Autocommand caused recursive behavior"));
+EXTERN char e_menuothermode[] INIT(= N_("E328: Menu only exists in another mode"));
 EXTERN char e_autocmd_close[] INIT(= N_("E813: Cannot close autocmd window"));
 EXTERN char e_listarg[] INIT(= N_("E686: Argument of %s must be a List"));
 EXTERN char e_unsupportedoption[] INIT(= N_("E519: Option not supported"));

src/nvim/menu.c

@@ -41,7 +41,6 @@
 static char *menu_mode_chars[] = { "n", "v", "s", "o", "i", "c", "tl", "t" };
 
 static char e_notsubmenu[] = N_("E327: Part of menu-item path is not sub-menu");
-static char e_othermode[] = N_("E328: Menu only exists in another mode");
 static char e_nomenu[] = N_("E329: No menu \"%s\"");
 
 // Return true if "name" is a window toolbar menu name.
@@ -573,7 +572,7 @@ static int remove_menu(vimmenu_T **menup, char *name, int modes, bool silent)
         }
       } else if (*name != NUL) {
         if (!silent) {
-          emsg(_(e_othermode));
+          emsg(_(e_menuothermode));
         }
         return FAIL;
       }
@@ -787,7 +786,7 @@ static vimmenu_T *find_menu(vimmenu_T *menu, char *name, int modes)
           emsg(_(e_notsubmenu));
           return NULL;
         } else if ((menu->modes & modes) == 0x0) {
-          emsg(_(e_othermode));
+          emsg(_(e_menuothermode));
           return NULL;
         } else if (*p == NUL) {  // found a full match
           return menu;

src/nvim/popupmnu.c

@@ -1008,6 +1008,13 @@ void pum_show_popupmenu(vimmenu_T *menu)
     }
   }
 
+  // When there are only Terminal mode menus, using "popup Edit" results in
+  // pum_size being zero.
+  if (pum_size <= 0) {
+    emsg(e_menuothermode);
+    return;
+  }
+
   int idx = 0;
   pumitem_T *array = (pumitem_T *)xcalloc((size_t)pum_size, sizeof(pumitem_T));
 

src/nvim/testdir/test_popup.vim

@@ -913,7 +913,7 @@ func Test_popup_complete_backwards_ctrl_p()
   bwipe!
 endfunc
 
-fun! Test_complete_o_tab()
+func Test_complete_o_tab()
   CheckFunction test_override
   let s:o_char_pressed = 0
 
@@ -922,7 +922,7 @@ fun! Test_complete_o_tab()
       let s:o_char_pressed = 0
       call feedkeys("\<c-x>\<c-n>", 'i')
     endif
-  endf
+  endfunc
 
   set completeopt=menu,noselect
   new
@@ -941,7 +941,21 @@ fun! Test_complete_o_tab()
   bwipe!
   set completeopt&
   delfunc s:act_on_text_changed
-endf
+endfunc
+
+func Test_menu_only_exists_in_terminal()
+  if !exists(':tlmenu') || has('gui_running')
+    return
+  endif
+  tlnoremenu  &Edit.&Paste<Tab>"+gP  <C-W>"+
+  aunmenu *
+  try
+    popup Edit
+    call assert_false(1, 'command should have failed')
+  catch
+    call assert_exception('E328:')
+  endtry
+endfunc
 
 func Test_popup_complete_info_01()
   new