patch 8.0.1164: changing StatusLine highlight does not always work

Problem:    Changing StatusLine highlight while evaluating 'statusline' may
            not change the status line color.
Solution:   When changing highlighting while redrawing don't cause another
            redraw. (suggested by Ozaki Kiichi, closes #2171, closes #2120)

src/buffer.c

@@ -3910,7 +3910,6 @@ build_stl_str_hl(
     struct stl_hlrec *sp;
     int		save_must_redraw = must_redraw;
     int		save_redr_type = curwin->w_redr_type;
-    int		save_highlight_shcnaged = need_highlight_changed;
 
 #ifdef FEAT_EVAL
     /*
@@ -4683,12 +4682,13 @@ build_stl_str_hl(
 	sp->userhl = 0;
     }
 
-    /* We do not want redrawing a stausline, ruler, title, etc. to trigger
+    /* When inside update_screen we do not want redrawing a stausline, ruler,
-     * another redraw, it may cause an endless loop.  This happens when a
+     * title, etc. to trigger another redraw, it may cause an endless loop. */
-     * statusline changes a highlight group. */
+    if (updating_screen)
+    {
 	must_redraw = save_must_redraw;
 	curwin->w_redr_type = save_redr_type;
-    need_highlight_changed = save_highlight_shcnaged;
+    }
 
     return width;
 }

src/syntax.c

@@ -7378,6 +7378,7 @@ do_highlight(
     int		id;
     int		idx;
     struct hl_group item_before;
+    int		did_change = FALSE;
     int		dodefault = FALSE;
     int		doclear = FALSE;
     int		dolink = FALSE;
@@ -7787,6 +7788,7 @@ do_highlight(
 		/* GUI not started yet, always accept the name. */
 		vim_free(HL_TABLE()[idx].sg_font_name);
 		HL_TABLE()[idx].sg_font_name = vim_strsave(arg);
+		did_change = TRUE;
 	    }
 	    else
 	    {
@@ -7815,6 +7817,7 @@ do_highlight(
 		    gui_mch_free_fontset(temp_sg_fontset);
 		    vim_free(HL_TABLE()[idx].sg_font_name);
 		    HL_TABLE()[idx].sg_font_name = vim_strsave(arg);
+		    did_change = TRUE;
 		}
 		else
 		    HL_TABLE()[idx].sg_fontset = temp_sg_fontset;
@@ -7826,6 +7829,7 @@ do_highlight(
 		    gui_mch_free_font(temp_sg_font);
 		    vim_free(HL_TABLE()[idx].sg_font_name);
 		    HL_TABLE()[idx].sg_font_name = vim_strsave(arg);
+		    did_change = TRUE;
 		}
 		else
 		    HL_TABLE()[idx].sg_font = temp_sg_font;
@@ -7991,6 +7995,7 @@ do_highlight(
 			    *namep = vim_strsave(arg);
 			else
 			    *namep = NULL;
+			did_change = TRUE;
 		    }
 # if defined(FEAT_GUI) || defined(FEAT_TERMGUICOLORS)
 #  ifdef FEAT_GUI_X11
@@ -8041,6 +8046,7 @@ do_highlight(
 			    *namep = vim_strsave(arg);
 			else
 			    *namep = NULL;
+			did_change = TRUE;
 		    }
 # if defined(FEAT_GUI) || defined(FEAT_TERMGUICOLORS)
 #  ifdef FEAT_GUI_X11
@@ -8090,6 +8096,7 @@ do_highlight(
 			    *namep = vim_strsave(arg);
 			else
 			    *namep = NULL;
+			did_change = TRUE;
 		    }
 # ifdef FEAT_GUI
 		}
@@ -8259,12 +8266,17 @@ do_highlight(
 
     /* Only call highlight_changed() once, after a sequence of highlight
      * commands, and only if an attribute actually changed. */
-    if (memcmp(&HL_TABLE()[idx], &item_before, sizeof(item_before)) != 0
+    if ((did_change
+	   || memcmp(&HL_TABLE()[idx], &item_before, sizeof(item_before)) != 0)
 #if defined(FEAT_GUI) || defined(FEAT_TERMGUICOLORS)
 	    && !did_highlight_changed
 #endif
        )
     {
+	/* Do not trigger a redraw when highlighting is changed while
+	 * redrawing.  This may happen when evaluating 'statusline' changes the
+	 * StatusLine group. */
+	if (!updating_screen)
 	    redraw_all_later(NOT_VALID);
 	need_highlight_changed = TRUE;
     }

src/version.c

@@ -761,6 +761,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1164,
 /**/
     1163,
 /**/