patch 8.2.1164: text cleared by checking terminal properties not redrawn

Problem:    Text cleared by checking terminal properties not redrawn. (Alexey
            Radkov)
Solution:   Mark the screen characters as invalid. (closes #6422)

src/proto/screen.pro

@@ -31,6 +31,7 @@ int screen_valid(int doclear);
 void screenalloc(int doclear);
 void free_screenlines(void);
 void screenclear(void);
+void line_was_clobbered(int screen_lnum);
 int can_clear(char_u *p);
 void screen_start(void);
 void windgoto(int row, int col);

src/screen.c

@@ -2981,6 +2981,16 @@ lineinvalid(unsigned off, int width)
     (void)vim_memset(ScreenAttrs + off, -1, (size_t)width * sizeof(sattr_T));
 }
 
+/*
+ * To be called when characters were sent to the terminal directly, outputting
+ * test on "screen_lnum".
+ */
+    void
+line_was_clobbered(int screen_lnum)
+{
+    lineinvalid(LineOffset[screen_lnum], (int)Columns);
+}
+
 /*
  * Copy part of a Screenline for vertically split window "wp".
  */

src/term.c

@@ -3732,6 +3732,7 @@ check_terminal_behavior(void)
 	screen_stop_highlight();
 	term_windgoto(1, 0);
 	out_str((char_u *)"  ");
+	line_was_clobbered(1);
     }
 
     if (xcc_status.tr_progress == STATUS_GET)
@@ -3761,6 +3762,7 @@ check_terminal_behavior(void)
 	screen_stop_highlight();
 	term_windgoto(2, 0);
 	out_str((char_u *)"           ");
+	line_was_clobbered(2);
     }
 
     if (did_send)

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1164,
 /**/
     1163,
 /**/