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Generated simulation and layout functions index past arrays or divide by zero for out-of-range counts #410
Description
Four functions index past their array, or divide by zero, for some inputs. The generated Rust then panics. The generated C reads out of bounds or traps with SIGFPE, and Zig safety checks trap. These hazards predate #409, which made these modules compile in Rust. They are not part of #399.
Reproduced on fix/rust-corpus-399 (59f39b6) with Rust 1.96.0, by calling the generated gen/rust modules directly:
| Function | Input | Result |
|---|---|---|
network_simulator::inject_fault |
fault_type = EVENT_NODE_FAILURE, target_id = 32 |
index out of bounds (MAX_NODES = 32) |
traffic_animator::update_animation_packets |
packet_count = 65 |
index out of bounds (MAX_PACKETS = 64) |
topology_visualizer::calculate_circular_layout |
node_count = 33 |
index out of bounds (MAX_NODES = 32) |
topology_visualizer::calculate_hierarchical_layout |
node_count = 3 |
division by zero (nodes_per_level = node_count / 4) |
network_simulator::process_event is safe: get_event_node_id masks the node id to 0..15.
Boundary:
- The fix goes in
specs/network_simulator.t27,specs/traffic_animator.t27andspecs/topology_visualizer.t27, with the pinned t27c regeneration of all three backends. Generated files are not edited by hand. - Public argument and return types stay unchanged.
Scenarios:
- An out-of-range id or count returns the module's existing failure value, or is clamped to the array length. The spec documents which.
calculate_hierarchical_layoutwithnode_count0..3 returns without dividing by zero.
Requirements:
- A
testblock in each spec covers the boundary inputs above. - A Rust test in
tests/exercises the same inputs againstgen/rust.
Success criteria:
- Every input in the table returns a defined value in Rust, C and Zig.
- The drift, Zig, C, Icarus and the
gen_rust_corpus_compilesgates stay green.
Refs #399
Dmitrii Fedorov (@dmitrii-f-t27)
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