/*

 * Copyright 2019 The Starlark in Rust Authors.

 * Copyright (c) Facebook, Inc. and its affiliates.

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     https://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#![no_main]

use libfuzzer_sys::fuzz_target;

use starlark::environment::Globals;

use starlark::environment::Module;

use starlark::eval::Evaluator;

use starlark::syntax::AstModule;

use starlark::syntax::Dialect;

fn run_arbitrary_starlark_err(content: &str) -> starlark::Result<String> {

    let ast: AstModule =

        AstModule::parse("hello_world.star", content.to_owned(), &Dialect::Standard)?;

    let globals: Globals = Globals::standard();

    let module: Module = Module::new();

    let mut eval: Evaluator = Evaluator::new(&module);

    let value = eval.eval_module(ast, &globals)?;

    Ok(format!("{value:?}"))

}

fn run_arbitrary_starlark(content: &str) -> String {

    match run_arbitrary_starlark_err(content) {

        Ok(v) => v,

        Err(e) => {

            const INTERNAL_ERROR: &str = "(internal error)";

            let s = format!("{e:?}");

            // We want to spot internal errors, but not encourage the fuzzer to write internal error in the input.

            // A sufficiently smart fuzzer might outwit us, but hopefully not too quickly.

            if s.contains(INTERNAL_ERROR) && !content.contains(INTERNAL_ERROR) {

                panic!("Internal error as anyhow::Error: {s}")

            }

            s

        }

    }

}

fuzz_target!(|content: &str| {

    let _ignore = run_arbitrary_starlark(content);

});