From 7246b229e136d0fc918b4ac98472fa92114d1a02 Mon Sep 17 00:00:00 2001
From: bruvzg <7645683+bruvzg@users.noreply.github.com>
Date: Fri, 17 Feb 2023 08:53:08 +0200
Subject: [PATCH] Set RTL minimal dash size to 2.0, add invalid dash size error
 to the `draw_dashed_line`.

---
 scene/gui/rich_text_label.cpp | 6 +++---
 scene/main/canvas_item.cpp    | 3 ++-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/scene/gui/rich_text_label.cpp b/scene/gui/rich_text_label.cpp
index 2c1c44322ad..973b02b3a31 100644
--- a/scene/gui/rich_text_label.cpp
+++ b/scene/gui/rich_text_label.cpp
@@ -1179,7 +1179,7 @@ int RichTextLabel::_draw_line(ItemFrame *p_frame, int p_line, const Vector2 &p_o
 				dot_ul_started = false;
 				float y_off = TS->shaped_text_get_underline_position(rid);
 				float underline_width = TS->shaped_text_get_underline_thickness(rid) * theme_cache.base_scale;
-				draw_dashed_line(dot_ul_start + Vector2(0, y_off), p_ofs + Vector2(off.x, off.y + y_off), dot_ul_color, underline_width, underline_width * 2);
+				draw_dashed_line(dot_ul_start + Vector2(0, y_off), p_ofs + Vector2(off.x, off.y + y_off), dot_ul_color, underline_width, MAX(2.0, underline_width * 2));
 			}
 			if (_find_strikethrough(it)) {
 				if (!st_started) {
@@ -1341,7 +1341,7 @@ int RichTextLabel::_draw_line(ItemFrame *p_frame, int p_line, const Vector2 &p_o
 						dot_ul_started = false;
 						float y_off = TS->shaped_text_get_underline_position(rid);
 						float underline_width = TS->shaped_text_get_underline_thickness(rid) * theme_cache.base_scale;
-						draw_dashed_line(dot_ul_start + Vector2(0, y_off), p_ofs + Vector2(off.x, off.y + y_off), dot_ul_color, underline_width, underline_width * 2);
+						draw_dashed_line(dot_ul_start + Vector2(0, y_off), p_ofs + Vector2(off.x, off.y + y_off), dot_ul_color, underline_width, MAX(2.0, underline_width * 2));
 					}
 					if (st_started) {
 						st_started = false;
@@ -1363,7 +1363,7 @@ int RichTextLabel::_draw_line(ItemFrame *p_frame, int p_line, const Vector2 &p_o
 			dot_ul_started = false;
 			float y_off = TS->shaped_text_get_underline_position(rid);
 			float underline_width = TS->shaped_text_get_underline_thickness(rid) * theme_cache.base_scale;
-			draw_dashed_line(dot_ul_start + Vector2(0, y_off), p_ofs + Vector2(off.x, off.y + y_off), dot_ul_color, underline_width, underline_width * 2);
+			draw_dashed_line(dot_ul_start + Vector2(0, y_off), p_ofs + Vector2(off.x, off.y + y_off), dot_ul_color, underline_width, MAX(2.0, underline_width * 2));
 		}
 		if (st_started) {
 			st_started = false;
diff --git a/scene/main/canvas_item.cpp b/scene/main/canvas_item.cpp
index 1c7d42ad360..b36353158b7 100644
--- a/scene/main/canvas_item.cpp
+++ b/scene/main/canvas_item.cpp
@@ -513,11 +513,12 @@ bool CanvasItem::is_y_sort_enabled() const {
 
 void CanvasItem::draw_dashed_line(const Point2 &p_from, const Point2 &p_to, const Color &p_color, real_t p_width, real_t p_dash, bool p_aligned) {
 	ERR_FAIL_COND_MSG(!drawing, "Drawing is only allowed inside NOTIFICATION_DRAW, _draw() function or 'draw' signal.");
+	ERR_FAIL_COND(p_dash <= 0.0);
 
 	float length = (p_to - p_from).length();
 	Vector2 step = p_dash * (p_to - p_from).normalized();
 
-	if (length < p_dash || step == Vector2() || p_dash <= 0.0) {
+	if (length < p_dash || step == Vector2()) {
 		RenderingServer::get_singleton()->canvas_item_add_line(canvas_item, p_from, p_to, p_color, p_width);
 		return;
 	}