Provide warning when using polygon shapes in `CollisionShape2D` node

`ConvexPolygonShape2D` and `ConcavePolygonShape2D` are only meant to be
used directly in code and not in the editor for physics-based use cases
specifically.

Developers are advised to use `CollisionPolygon2D` instead, which does
generate those shapes under the hood, handling polygon convexivity,
proper orientation etc.

2 files changed, 7 insertions, 2 deletions

diff --git a/editor/plugins/collision_shape_2d_editor_plugin.cpp b/editor/plugins/collision_shape_2d_editor_plugin.cpp
index 596629f8e8..105ac24950 100644
--- a/editor/plugins/collision_shape_2d_editor_plugin.cpp
+++ b/editor/plugins/collision_shape_2d_editor_plugin.cpp
@@ -242,9 +242,11 @@ void CollisionShape2DEditor::commit_handle(int idx, Variant &p_org) {
 		} break;
 
 		case CONCAVE_POLYGON_SHAPE: {
+			// Cannot be edited directly, use CollisionPolygon2D instead.
 		} break;
 
 		case CONVEX_POLYGON_SHAPE: {
+			// Cannot be edited directly, use CollisionPolygon2D instead.
 		} break;
 
 		case LINE_SHAPE: {
diff --git a/scene/2d/collision_shape_2d.cpp b/scene/2d/collision_shape_2d.cpp
index 88d124536c..d022c857f3 100644
--- a/scene/2d/collision_shape_2d.cpp
+++ b/scene/2d/collision_shape_2d.cpp
@@ -176,11 +176,14 @@ String CollisionShape2D::get_configuration_warning() const {
 	if (!Object::cast_to<CollisionObject2D>(get_parent())) {
 		return TTR("CollisionShape2D only serves to provide a collision shape to a CollisionObject2D derived node. Please only use it as a child of Area2D, StaticBody2D, RigidBody2D, KinematicBody2D, etc. to give them a shape.");
 	}
-
 	if (!shape.is_valid()) {
 		return TTR("A shape must be provided for CollisionShape2D to function. Please create a shape resource for it!");
 	}
-
+	Ref<ConvexPolygonShape2D> convex = shape;
+	Ref<ConcavePolygonShape2D> concave = shape;
+	if (convex.is_valid() || concave.is_valid()) {
+		return TTR("Polygon-based shapes are not meant be used nor edited directly through the CollisionShape2D node. Please use the CollisionPolygon2D node instead.");
+	}
 	return String();
 }