Merge pull request #774 from silvergasp/main

fuzz: Add a fuzz-testing harness

Cargo.toml

@@ -37,6 +37,7 @@ rust_decimal = { version = "1.16.0", default-features = false, features = ["math
 getrandom = { version = "0.2.0", optional = true }
 rustyline = { version = "12.0.0", optional = true }
 document-features = { version = "0.2.0", optional = true }
+arbitrary = { version = "1.3.2", optional = true, features = ["derive"] }
 
 [dev-dependencies]
 rmp-serde = "1.1.0"

fuzz/.gitignore

@@ -0,0 +1,4 @@
+target
+corpus
+artifacts
+coverage

fuzz/Cargo.toml

@@ -0,0 +1,29 @@
+[package]
+name = "rhai-fuzz"
+version = "0.0.0"
+publish = false
+edition = "2018"
+
+[package.metadata]
+cargo-fuzz = true
+
+[dependencies]
+arbitrary = { version = "1.3.2", features = ["derive"] }
+libfuzzer-sys = "0.4"
+
+[dependencies.rhai]
+path = ".."
+features = ["arbitrary"]
+
+# Prevent this from interfering with workspaces
+[workspace]
+members = ["."]
+
+[profile.release]
+debug = 1
+
+[[bin]]
+name = "scripting"
+path = "fuzz_targets/scripting.rs"
+test = false
+doc = false

fuzz/fuzz_targets/scripting.rs

@@ -0,0 +1,36 @@
+#![no_main]
+use rhai::{Dynamic, Engine, OptimizationLevel};
+
+use arbitrary::Arbitrary;
+use libfuzzer_sys::fuzz_target;
+use std::time::{Duration, Instant};
+
+#[derive(Debug, Clone, Arbitrary)]
+struct Ctx<'a> {
+    script: &'a str,
+    optimization_level: OptimizationLevel,
+}
+
+fuzz_target!(|ctx: Ctx| {
+    let mut engine = Engine::new();
+    engine.set_max_string_size(1000);
+    engine.set_max_array_size(500);
+    engine.set_max_map_size(500);
+    engine.set_max_variables(1000);
+    engine.set_max_modules(1000);
+    engine.set_max_call_levels(10);
+    engine.set_max_expr_depths(50, 5);
+    engine.set_optimization_level(ctx.optimization_level);
+    let start = Instant::now();
+    engine.on_progress(move |_| {
+        // We need fuzzing to be fast, so we'll stop executing after 1s.
+        if start.elapsed() > Duration::from_secs(1) {
+            Some(Dynamic::UNIT)
+        } else {
+            None
+        }
+    });
+    let engine = engine;
+
+    _ = engine.run(ctx.script);
+});

src/optimizer.rs

@@ -31,6 +31,7 @@ use std::{
 ///
 /// Not available under `no_optimize`.
 #[derive(Debug, Eq, PartialEq, Clone, Copy, Default, Hash)]
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 #[non_exhaustive]
 pub enum OptimizationLevel {
     /// No optimization performed.