Cursor rule

1---
2description: Fuzzing setup and guidelines for skia-rs
3globs: ["fuzz/**"]
4alwaysApply: false
5---
6 
7# Fuzzing
8 
9## Setup
10 
11```bash
12# Install nightly toolchain and cargo-fuzz
13rustup install nightly
14cargo install cargo-fuzz
15```
16 
17## Running Fuzz Tests
18 
19```bash
20# Run a fuzz target
21cd fuzz
22cargo +nightly fuzz run fuzz_point
23 
24# Run with time limit
25cargo +nightly fuzz run fuzz_matrix -- -max_total_time=60
26 
27# List all targets
28cargo +nightly fuzz list
29```
30 
31## Available Fuzz Targets
32 
33- `fuzz_point` - Point operations
34- `fuzz_rect` - Rectangle operations
35- `fuzz_matrix` - Matrix transformations
36- `fuzz_color` - Color conversions
37- `fuzz_path` - Path construction
38- `fuzz_path_builder` - PathBuilder shapes
39- `fuzz_paint` - Paint configuration
40- `fuzz_canvas` - Canvas operations
41 
42## Writing Fuzz Targets
43 
44```rust
45#![no_main]
46 
47use arbitrary::Arbitrary;
48use libfuzzer_sys::fuzz_target;
49 
50#[derive(Debug, Arbitrary)]
51struct MyInput {
52    value: f32,
53    flag: bool,
54}
55 
56fuzz_target!(|input: MyInput| {
57    // Skip invalid inputs early
58    if !input.value.is_finite() {
59        return;
60    }
61 
62    // Test code that should not panic
63    let result = my_function(input.value);
64 
65    // Assert invariants
66    assert!(result.is_valid());
67});
68```
69 
70## Best Practices
71 
72- Use `Arbitrary` derive for structured input
73- Validate and skip invalid inputs early
74- Limit resource usage (iteration counts, sizes)
75- Assert invariants, not expected failures
76- Keep fuzz targets focused on specific functionality
77- The `fuzz` crate uses `edition = "2021"` due to `libfuzzer-sys` requirements
78