Fix crash on deleting all subpaths (#1460)

* Fix crash on deleting all subpaths

* Delete layer if no manipulators exist

editor/src/messages/portfolio/document/node_graph/graph_operation_message_handler.rs

@@ -424,6 +424,7 @@ impl<'a> ModifyInputsContext<'a> {
 
 		let [mut old_bounds_min, mut old_bounds_max] = [DVec2::ZERO, DVec2::ONE];
 		let [mut new_bounds_min, mut new_bounds_max] = [DVec2::ZERO, DVec2::ONE];
+		let mut empty = false;
 
 		self.modify_inputs("Shape", false, |inputs, _node_id, _metadata| {
 			let [subpaths, mirror_angle_groups] = inputs.as_mut_slice() else {
@@ -448,11 +449,17 @@ impl<'a> ModifyInputsContext<'a> {
 			[old_bounds_min, old_bounds_max] = transform_utils::nonzero_subpath_bounds(subpaths);
 
 			transform_utils::VectorModificationState { subpaths, mirror_angle_groups }.modify(modification);
+			empty = !subpaths.iter().any(|subpath| !subpath.is_empty());
 
 			[new_bounds_min, new_bounds_max] = transform_utils::nonzero_subpath_bounds(subpaths);
 		});
 
 		self.update_bounds([old_bounds_min, old_bounds_max], [new_bounds_min, new_bounds_max]);
+		if empty {
+			if let Some(layer) = self.layer_node {
+				self.responses.add(DocumentMessage::DeleteLayer { layer_path: vec![layer] })
+			}
+		}
 	}
 
 	fn brush_modify(&mut self, strokes: Vec<BrushStroke>) {

libraries/bezier-rs/src/subpath/core.rs

@@ -141,6 +141,9 @@ impl<ManipulatorGroupId: crate::Identifier> Subpath<ManipulatorGroupId> {
 
 	/// Write the curve argument to the string (the d="..." part)
 	pub fn subpath_to_svg(&self, svg: &mut String, transform: glam::DAffine2) -> std::fmt::Result {
+		if self.is_empty() {
+			return Ok(());
+		}
 		let start = transform.transform_point2(self[0].anchor);
 		write!(svg, "{SVG_ARG_MOVE}{},{}", start.x, start.y)?;
 		for bezier in self.iter() {

libraries/bezier-rs/src/subpath/mod.rs

@@ -51,6 +51,9 @@ impl<ManipulatorGroupId: crate::Identifier> Iterator for SubpathIter<'_, Manipul
 
 	// Returns the Bezier representation of each `Subpath` segment, defined between a pair of adjacent manipulator points.
 	fn next(&mut self) -> Option<Self::Item> {
+		if self.subpath.is_empty() {
+			return None;
+		}
 		let len = self.subpath.len() - 1
 			+ match self.subpath.closed {
 				true => 1,