Prohibit inconsistent size state for SubViewport

Prohibit size changes of SubViewports with parent SubViewportContainers that have stretch mode enabled.

1 files changed, 18 insertions, 1 deletions

diff --git a/scene/main/viewport.cpp b/scene/main/viewport.cpp
index 234cebd821..430725f2bf 100644
--- a/scene/main/viewport.cpp
+++ b/scene/main/viewport.cpp
@@ -4080,9 +4080,26 @@ Viewport::~Viewport() {
 /////////////////////////////////
 
 void SubViewport::set_size(const Size2i &p_size) {
-	_set_size(p_size, _get_size_2d_override(), Rect2i(), _stretch_transform(), true);
+	_internal_set_size(p_size);
+}
 
+void SubViewport::set_size_force(const Size2i &p_size) {
+	// Use only for setting the size from the parent SubViewportContainer with enabled stretch mode.
+	// Don't expose function to scripting.
+	_internal_set_size(p_size, true);
+}
+
+void SubViewport::_internal_set_size(const Size2i &p_size, bool p_force) {
 	SubViewportContainer *c = Object::cast_to<SubViewportContainer>(get_parent());
+	if (!p_force && c && c->is_stretch_enabled()) {
+#ifdef DEBUG_ENABLED
+		WARN_PRINT("Can't change the size of a `SubViewport` with a `SubViewportContainer` parent that has `stretch` enabled. Set `SubViewportContainer.stretch` to `false` to allow changing the size manually.");
+#endif // DEBUG_ENABLED
+		return;
+	}
+
+	_set_size(p_size, _get_size_2d_override(), Rect2i(), _stretch_transform(), true);
+
 	if (c) {
 		c->update_minimum_size();
 	}