tree-splicer

tree-splicer is a simple grammar-based test case generator. It parses a number of input files using tree-sitter grammars, and produces new files formed by splicing together their ASTs.

tree-splicer generates test cases in the tree-crasher fuzzer and in icemaker, though it can also be used as a standalone tool.

tree-sitter grammars are resistant to syntax errors. Therefore, tree-splicer can even mutate syntactically-invalid inputs! You can also use tree-splicer with an incomplete grammar.

Example

Given this simple Rust program:

```rust use std::env;

fn even(x: usize) -> bool { if x % 2 == 0 { return true; } else { return false; } }

fn main() -> () { let argc = env::args().len(); println!("Hello, world!"); if even(argc) { println!("Even!"); } else { println!("Odd!"); } return (); } ```

Here are a few candidates created by tree-splicer-rust:

```rust use even::env;

fn even() -> bool { if even(argc) { println!("Even!"); } else { println!("Odd!"); } }

fn std() -> () { return true; } rust use args::env;

fn argc(main: usize) -> bool { return true; }

fn even(x: usize) -> bool { if x % 2 == 0 { return true; } else { return false; } } rust use std::env;

fn x(x: usize) -> bool { return true; }

fn x(x: usize) -> () { return false; } ```

Supported languages

Languages are easy to add, see PR #3 for an example.

Bugs found

boa

#2717 #2718 #2719

clang

#61635 #61666 #61667

deno

#18338

rustc

#109066 #109071 #109072 #109078 #109079 #109090 #109129 #109141 #109143 #109144 #109146 #109147 #109148 #109152 #109178 #109188 #109191 #109204 #109232 #109239 #109296 #109297 #109298 #109299 #109300 #109304 #109305

rustfmt

#5716

Installation

From a release

Statically-linked Linux binaries are available on the releases page.

From crates.io

You can build a released version from crates.io. You'll need the Rust compiler and the Cargo build tool. rustup makes it very easy to obtain these. Then, to install the generator for the language <LANG>, run:

cargo install tree-splicer-<LANG>

This will install binaries in ~/.cargo/bin by default.

Build

To build from source, you'll need the Rust compiler and the Cargo build tool. rustup makes it very easy to obtain these. Then, get the source:

bash git clone https://github.com/langston-barrett/tree-splicer cd tree-splicer

Finally, build everything:

bash cargo build --release

You can find binaries in target/release. Run tests with cargo test.