patch 8.2.4638: superfluous check if a redraw is needed for 'cursorline'

Problem:    Superfluous check if a redraw is needed for 'cursorline'.
Solution:   Remove check_redraw_cursorline(). (closes #10030, closes #10029)

src/drawscreen.c

@@ -3032,23 +3032,6 @@ redraw_asap(int type)
 }
 #endif
 
-#if defined(FEAT_SYN_HL) || defined(PROTO)
-/*
- * Check if the cursor moved and 'cursorline' is set.  Mark for a VALID redraw
- * if needed.
- */
-    void
-check_redraw_cursorline(void)
-{
-    // When 'cursorlineopt' is "screenline" need to redraw always.
-    if (curwin->w_p_cul
-	    && (curwin->w_last_cursorline != curwin->w_cursor.lnum
-		|| (curwin->w_p_culopt_flags & CULOPT_SCRLINE))
-	    && !char_avail())
-	redraw_later(VALID);
-}
-#endif
-
 /*
  * Invoked after an asynchronous callback is called.
  * If an echo command was used the cursor needs to be put back where
@@ -3093,10 +3076,9 @@ redraw_after_callback(int call_update_screen, int do_message)
     }
     else if (State & (NORMAL | INSERT | TERMINAL))
     {
-#ifdef FEAT_SYN_HL
-	// might need to update for 'cursorline'
-	check_redraw_cursorline();
-#endif
+	update_topline();
+	validate_cursor();
+
 	// keep the command line if possible
 	update_screen(VALID_NO_UPDATE);
 	setcursor();

src/edit.c

@@ -1058,10 +1058,6 @@ doESCkey:
 	case K_COMMAND:		    // <Cmd>command<CR>
 	case K_SCRIPT_COMMAND:	    // <ScriptCmd>command<CR>
 	    do_cmdkey_command(c, 0);
-#ifdef FEAT_SYN_HL
-	    // Might need to update for 'cursorline'.
-	    check_redraw_cursorline();
-#endif
 #ifdef FEAT_TERMINAL
 	    if (term_use_loop())
 		// Started a terminal that gets the input, exit Insert mode.

src/main.c

@@ -1384,10 +1384,6 @@ main_loop(
 	    update_topline();
 	    validate_cursor();
 
-#ifdef FEAT_SYN_HL
-	    // Might need to update for 'cursorline'.
-	    check_redraw_cursorline();
-#endif
 	    if (VIsual_active)
 		update_curbuf(INVERTED); // update inverted part
 	    else if (must_redraw)

src/move.c

@@ -135,6 +135,26 @@ redraw_for_cursorline(win_T *wp)
     }
 }
 
+#ifdef FEAT_SYN_HL
+/*
+ * Redraw when w_virtcol changes and 'cursorcolumn' is set or 'cursorlineopt'
+ * contains "screenline".
+ */
+    static void
+redraw_for_cursorcolumn(win_T *wp)
+{
+    if ((wp->w_valid & VALID_VIRTCOL) == 0 && !pum_visible())
+    {
+	// When 'cursorcolumn' is set need to redraw with SOME_VALID.
+	if (wp->w_p_cuc)
+	    redraw_later(SOME_VALID);
+	// When 'cursorlineopt' contains "screenline" need to redraw with VALID.
+	else if (wp->w_p_cul && (wp->w_p_culopt_flags & CULOPT_SCRLINE))
+	    redraw_later(VALID);
+    }
+}
+#endif
+
 /*
  * Update curwin->w_topline and redraw if necessary.
  * Used to update the screen before printing a message.
@@ -798,11 +818,10 @@ validate_virtcol_win(win_T *wp)
     if (!(wp->w_valid & VALID_VIRTCOL))
     {
 	getvvcol(wp, &wp->w_cursor, NULL, &(wp->w_virtcol), NULL);
-	wp->w_valid |= VALID_VIRTCOL;
 #ifdef FEAT_SYN_HL
-	if (wp->w_p_cuc && !pum_visible())
-	    redraw_win_later(wp, SOME_VALID);
+	redraw_for_cursorcolumn(wp);
 #endif
+	wp->w_valid |= VALID_VIRTCOL;
     }
 }
 
@@ -1169,10 +1188,7 @@ curs_columns(
 	redraw_later(NOT_VALID);
 
 #ifdef FEAT_SYN_HL
-    // Redraw when w_virtcol changes and 'cursorcolumn' is set
-    if (curwin->w_p_cuc && (curwin->w_valid & VALID_VIRTCOL) == 0
-	    && !pum_visible())
-	redraw_later(SOME_VALID);
+    redraw_for_cursorcolumn(curwin);
 #endif
 #if defined(FEAT_PROP_POPUP) && defined(FEAT_TERMINAL)
     if (popup_is_popup(curwin) && curbuf->b_term != NULL)

src/normal.c

@@ -6971,10 +6971,6 @@ nv_edit(cmdarg_T *cap)
 	    coladvance(getviscol());
 	    State = save_State;
 	}
-#ifdef FEAT_SYN_HL
-	// Might need to update for 'cursorline'.
-	check_redraw_cursorline();
-#endif
 
 	invoke_edit(cap, FALSE, cap->cmdchar, FALSE);
     }

src/proto/drawscreen.pro

@@ -8,7 +8,6 @@ void update_curbuf(int type);
 void update_debug_sign(buf_T *buf, linenr_T lnum);
 void updateWindow(win_T *wp);
 int redraw_asap(int type);
-void check_redraw_cursorline(void);
 void redraw_after_callback(int call_update_screen, int do_message);
 void redraw_later(int type);
 void redraw_win_later(win_T *wp, int type);

src/testdir/dumps/Test_cursorcolumn_callback_1.dump

@@ -0,0 +1,8 @@
+>a+0&#ffffff0@4| @69
+|b+0&#e0e0e08|b+0&#ffffff0@3| @69
+|c+0&#e0e0e08|c+0&#ffffff0@3| @69
+|d+0&#e0e0e08|d+0&#ffffff0@3| @69
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|4|,|5| @10|A|l@1| 

src/testdir/dumps/Test_relativenumber_callback_1.dump

@@ -0,0 +1,8 @@
+| +0#af5f00255#ffffff0@1|0| >a+0#0000000&@4| @65
+| +0#af5f00255&@1|1| |b+0#0000000&@4| @65
+| +0#af5f00255&@1|2| |c+0#0000000&@4| @65
+| +0#af5f00255&@1|3| |d+0#0000000&@4| @65
+|~+0#4040ff13&| @73
+|~| @73
+|~| @73
+| +0#0000000&@56|4|,|1| @10|A|l@1| 

src/testdir/test_highlight.vim

@@ -592,6 +592,31 @@ func Test_cursorline_with_visualmode()
   call delete('Xtest_cursorline_with_visualmode')
 endfunc
 
+func Test_cursorcolumn_callback()
+  CheckScreendump
+  CheckFeature timers
+
+  let lines =<< trim END
+      call setline(1, ['aaaaa', 'bbbbb', 'ccccc', 'ddddd'])
+      set cursorcolumn
+      call cursor(4, 5)
+
+      func Func(timer)
+        call cursor(1, 1)
+      endfunc
+
+      call timer_start(300, 'Func')
+  END
+  call writefile(lines, 'Xcuc_timer')
+
+  let buf = RunVimInTerminal('-S Xcuc_timer', #{rows: 8})
+  call TermWait(buf, 310)
+  call VerifyScreenDump(buf, 'Test_cursorcolumn_callback_1', {})
+
+  call StopVimInTerminal(buf)
+  call delete('Xcuc_timer')
+endfunc
+
 func Test_wincolor()
   CheckScreendump
   " make sure the width is enough for the test

src/testdir/test_number.vim

@@ -298,6 +298,31 @@ func Test_relativenumber_colors()
   call delete('XTest_relnr')
 endfunc
 
+func Test_relativenumber_callback()
+  CheckScreendump
+  CheckFeature timers
+
+  let lines =<< trim END
+      call setline(1, ['aaaaa', 'bbbbb', 'ccccc', 'ddddd'])
+      set relativenumber
+      call cursor(4, 1)
+
+      func Func(timer)
+        call cursor(1, 1)
+      endfunc
+
+      call timer_start(300, 'Func')
+  END
+  call writefile(lines, 'Xrnu_timer')
+
+  let buf = RunVimInTerminal('-S Xrnu_timer', #{rows: 8})
+  call TermWait(buf, 310)
+  call VerifyScreenDump(buf, 'Test_relativenumber_callback_1', {})
+
+  call StopVimInTerminal(buf)
+  call delete('Xrnu_timer')
+endfunc
+
 " Test for displaying line numbers with 'rightleft'
 func Test_number_rightleft()
   CheckFeature rightleft

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4638,
 /**/
     4637,
 /**/