patch 8.2.2685: custom statusline not drawn correctly with WinBar

Problem:    Custom statusline not drawn correctly with WinBar.
Solution:   Also adjust the column for the custom status line. (Yee Cheng
            Chin, closes #8047)

src/drawscreen.c

@@ -380,7 +380,7 @@ update_screen(int type_arg)
 /*
  * Return the row for drawing the statusline and the ruler of window "wp".
  */
-    static int
+    int
 statusline_row(win_T *wp)
 {
 #if defined(FEAT_PROP_POPUP)

src/proto/drawscreen.pro

@@ -1,5 +1,6 @@
 /* drawscreen.c */
 int update_screen(int type_arg);
+int statusline_row(win_T *wp);
 void showruler(int always);
 void win_redr_ruler(win_T *wp, int always, int ignore_pum);
 void after_updating_screen(int may_resize_shell);

src/screen.c

@@ -1248,7 +1248,7 @@ win_redr_custom(
     }
     else
     {
-	row = W_WINROW(wp) + wp->w_height;
+	row = statusline_row(wp);
 	fillchar = fillchar_status(&attr, wp);
 	maxwidth = wp->w_width;
 

src/testdir/dumps/Test_winbar_not_visible_custom_statusline.dump

@@ -0,0 +1,10 @@
+|a+1&#ffffff0|b|c|d|e| @69
+> +0&&@74
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|~| @73
+|a+3#0000000&|b|c|d|e| @69
+| +0&&@74

src/testdir/test_winbar.vim

@@ -141,4 +141,24 @@ func Test_winbar_not_visible()
   call delete('XtestWinbarNotVisble')
 endfunction
 
+func Test_winbar_not_visible_custom_statusline()
+  CheckScreendump
+
+  let lines =<< trim END
+      split
+      nnoremenu WinBar.Test :test
+      set winminheight=0
+      set statusline=abcde
+      wincmd j
+      wincmd _
+  END
+  call writefile(lines, 'XtestWinbarNotVisble')
+  let buf = RunVimInTerminal('-S XtestWinbarNotVisble', #{rows: 10})
+  call VerifyScreenDump(buf, 'Test_winbar_not_visible_custom_statusline', {})
+
+  " clean up
+  call StopVimInTerminal(buf)
+  call delete('XtestWinbarNotVisble')
+endfunction
+
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2685,
 /**/
     2684,
 /**/