Crash / integer underflow in Index Points node

[0HyperCube]

Reproduce

• New document
• Open node graph
• Create «Path node»
• Connect output to «Index Points»
• Connect output to the «Line» node (you must expose one of the inputs to the node graph by clicking on the circle)
• Connect output to graph output

Reproduction file: index_points_underflow.graphite.json (file -> open then remove any file extension filtering to see it)

Cause

The crash only occurs in debug mode:

frontend/wasm/src/lib.rs:45
Node graph evaluation panicked panicked at node-graph/nodes/vector/src/vector_nodes.rs:2283:30:
attempt to subtract with overflow

If index is >= 0 (as is default) and points_count is 0 then there is underflow

Graphite/node-graph/nodes/vector/src/vector_nodes.rs

Lines 2276 to 2284 in 1b91198

	let points_count = content.iter().map(|row| row.element.point_domain.positions().len()).sum::<usize>();
	// Clamp and allow negative indexing from the end
	let index = index as isize;
	let index = if index < 0 {
	(points_count as isize + index).max(0) as usize
	} else {
	(index as usize).min(points_count - 1)
	};

[jsjgdh]

Fixed in PR #3623