From eb44e23ca303a17898dbf4d237417e788cf3fd42 Mon Sep 17 00:00:00 2001
From: bruvzg <7645683+bruvzg@users.noreply.github.com>
Date: Mon, 23 May 2022 18:01:03 +0300
Subject: [PATCH] [Label3D, 3.x] Monitor default theme font changes, to prevent
 use of invalid materials.

---
 scene/3d/label_3d.cpp | 26 +++++++++++++++++++++++---
 scene/3d/label_3d.h   |  1 +
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/scene/3d/label_3d.cpp b/scene/3d/label_3d.cpp
index 6542ec8ce54..00c95063a99 100644
--- a/scene/3d/label_3d.cpp
+++ b/scene/3d/label_3d.cpp
@@ -866,6 +866,11 @@ Ref<Font> Label3D::get_font() const {
 }
 
 Ref<Font> Label3D::_get_font_or_default() const {
+	if (theme_font.is_valid()) {
+		theme_font->disconnect(CoreStringNames::get_singleton()->changed, const_cast<Label3D *>(this), "_font_changed");
+		theme_font.unref();
+	}
+
 	if (font_override.is_valid()) {
 		return font_override;
 	}
@@ -877,7 +882,12 @@ Ref<Font> Label3D::_get_font_or_default() const {
 
 		for (List<StringName>::Element *E = theme_types.front(); E; E = E->next()) {
 			if (Theme::get_project_default()->has_theme_item(Theme::DATA_TYPE_FONT, "font", E->get())) {
-				return Theme::get_project_default()->get_theme_item(Theme::DATA_TYPE_FONT, "font", E->get());
+				Ref<Font> f = Theme::get_project_default()->get_theme_item(Theme::DATA_TYPE_FONT, "font", E->get());
+				if (f.is_valid()) {
+					theme_font = f;
+					theme_font->connect(CoreStringNames::get_singleton()->changed, const_cast<Label3D *>(this), "_font_changed");
+				}
+				return f;
 			}
 		}
 	}
@@ -889,13 +899,23 @@ Ref<Font> Label3D::_get_font_or_default() const {
 
 		for (List<StringName>::Element *E = theme_types.front(); E; E = E->next()) {
 			if (Theme::get_default()->has_theme_item(Theme::DATA_TYPE_FONT, "font", E->get())) {
-				return Theme::get_default()->get_theme_item(Theme::DATA_TYPE_FONT, "font", E->get());
+				Ref<Font> f = Theme::get_default()->get_theme_item(Theme::DATA_TYPE_FONT, "font", E->get());
+				if (f.is_valid()) {
+					theme_font = f;
+					theme_font->connect(CoreStringNames::get_singleton()->changed, const_cast<Label3D *>(this), "_font_changed");
+				}
+				return f;
 			}
 		}
 	}
 
 	// If they don't exist, use any type to return the default/empty value.
-	return Theme::get_default()->get_theme_item(Theme::DATA_TYPE_FONT, "font", StringName());
+	Ref<Font> f = Theme::get_default()->get_theme_item(Theme::DATA_TYPE_FONT, "font", StringName());
+	if (f.is_valid()) {
+		theme_font = f;
+		theme_font->connect(CoreStringNames::get_singleton()->changed, const_cast<Label3D *>(this), "_font_changed");
+	}
+	return f;
 }
 
 void Label3D::set_modulate(const Color &p_color) {
diff --git a/scene/3d/label_3d.h b/scene/3d/label_3d.h
index c82e19c622e..ab578a257d0 100644
--- a/scene/3d/label_3d.h
+++ b/scene/3d/label_3d.h
@@ -124,6 +124,7 @@ private:
 	float width = 500.0;
 
 	Ref<Font> font_override;
+	mutable Ref<Font> theme_font;
 	Color modulate = Color(1, 1, 1, 1);
 	Point2 lbl_offset;
 	int outline_render_priority = -1;