patch 8.2.2686: status line is not updated when going to cmdline mode

Problem:    Status line is not updated when going to cmdline mode.
Solution:   Redraw status lines if 'statusline' is set and going to status
            line mode. (based on patch from Justin M. Keyes et al.,
            closes #8044)

src/ex_getln.c

@@ -1706,6 +1706,15 @@ getcmdline_int(
     // and execute commands. Display may be messed up a bit.
     if (did_emsg)
 	redrawcmd();
+
+    // Redraw the statusline in case it uses the current mode using the mode()
+    // function.
+    if (!cmd_silent && msg_scrolled == 0 && *p_stl != NUL)
+    {
+	curwin->w_redr_status = TRUE;
+	redraw_statuslines();
+    }
+
     did_emsg = FALSE;
     got_int = FALSE;
 

src/testdir/dumps/Test_statusline_mode_1.dump

@@ -0,0 +1,5 @@
+> +0&#ffffff0@49
+|~+0#4040ff13&| @48
+|~| @48
+|-+3#0000000&|n|-| @46
+| +0&&@49

src/testdir/dumps/Test_statusline_mode_2.dump

@@ -0,0 +1,5 @@
+| +0&#ffffff0@49
+|~+0#4040ff13&| @48
+|~| @48
+|-+3#0000000&|c|-| @46
+|:+0&&> @48

src/testdir/test_statusline.vim

@@ -448,6 +448,27 @@ func Test_statusline_removed_group()
   call delete('XTest_statusline')
 endfunc
 
+func Test_statusline_using_mode()
+  CheckScreendump
+
+  let lines =<< trim END
+    set laststatus=2
+    let &statusline = '-%{mode()}-'
+  END
+  call writefile(lines, 'XTest_statusline')
+
+  let buf = RunVimInTerminal('-S XTest_statusline', {'rows': 5, 'cols': 50})
+  call VerifyScreenDump(buf, 'Test_statusline_mode_1', {})
+
+  call term_sendkeys(buf, ":")
+  call VerifyScreenDump(buf, 'Test_statusline_mode_2', {})
+
+  " clean up
+  call term_sendkeys(buf, "\<CR>")
+  call StopVimInTerminal(buf)
+  call delete('XTest_statusline')
+endfunc
+
 func Test_statusline_after_split_vsplit()
   only
 

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2686,
 /**/
     2685,
 /**/