vim-patch:8.2.5109: mode not updated after CTRL-O CTRL-C in Insert mode

Problem:    Mode not updated after CTRL-O CTRL-C in Insert mode.
Solution:   Set redraw_mode and use it. (closes vim/vim#10581)
7a1d32809b

src/nvim/normal.c

@@ -1284,7 +1284,7 @@ static void normal_redraw(NormalState *s)
     update_screen(INVERTED);
   } else if (must_redraw) {
     update_screen(0);
-  } else if (redraw_cmdline || clear_cmdline) {
+  } else if (redraw_cmdline || clear_cmdline || redraw_mode) {
     showmode();
   }
 
@@ -6930,6 +6930,10 @@ static void nv_esc(cmdarg_T *cap)
       }
     }
 
+    if (restart_edit != 0) {
+      redraw_mode = true;  // remove "-- (insert) --"
+    }
+
     restart_edit = 0;
 
     if (cmdwin_type != 0) {

src/nvim/testdir/test_normal.vim

@@ -3,6 +3,7 @@
 source shared.vim
 source check.vim
 source view_util.vim
+source screendump.vim
 
 func Setup_NewWindow()
   10new
@@ -2889,6 +2890,20 @@ func Test_message_when_using_ctrl_c()
   bwipe!
 endfunc
 
+func Test_mode_updated_after_ctrl_c()
+  CheckScreendump
+
+  let buf = RunVimInTerminal('', {'rows': 5})
+  call term_sendkeys(buf, "i")
+  call term_sendkeys(buf, "\<C-O>")
+  " wait a moment so that the "-- (insert) --" message is displayed
+  call TermWait(buf, 50)
+  call term_sendkeys(buf, "\<C-C>")
+  call VerifyScreenDump(buf, 'Test_mode_updated_1', {})
+
+  call StopVimInTerminal(buf)
+endfunc
+
 " Test for '[m', ']m', '[M' and ']M'
 " Jumping to beginning and end of methods in Java-like languages
 func Test_java_motion()

test/functional/legacy/messages_spec.lua

@@ -402,6 +402,28 @@ describe('messages', function()
                                                 |
       ]])
     end)
+
+    -- oldtest: Test_mode_updated_after_ctrl_c()
+    it('pressing Ctrl-C in i_CTRL-O', function()
+      feed('i<C-O>')
+      screen:expect([[
+        ^                                        |
+        {1:~                                       }|
+        {1:~                                       }|
+        {1:~                                       }|
+        {1:~                                       }|
+        {2:-- (insert) --}                          |
+      ]])
+      feed('<C-C>')
+      screen:expect([[
+        ^                                        |
+        {1:~                                       }|
+        {1:~                                       }|
+        {1:~                                       }|
+        {1:~                                       }|
+                                                |
+      ]])
+    end)
   end)
 
   -- oldtest: Test_ask_yesno()