Option::unwrap panic in parser when ENABLE_HEADING_ATTRIBUTES is set

[5225225]

I have come bearing gifts. (When looking up the spelling of that, I just learned the phrase was about the trojan horse. Neat.)

But inside of the horse is a fuzzer panic.

#[test]
fn test_bad_heading_attribute() {
    let mut opts = pulldown_cmark::Options::empty();

    opts.insert(Options::ENABLE_HEADING_ATTRIBUTES);

    let data = "[[][({][}\n-";

    for _ in pulldown_cmark::Parser::new_ext(data, opts) {};
}

This took a whole 10k seconds of CPU time, or 2 hours of wall clock time to find. So we are definitely making progress!

[5225225]

(This was fuzzed directly against the #564 PR, commit 209b248)

[marcusklaas]

This should be fixed by that PR now as well. I have since fuzzed myself for a few hours, and found nothing!

[5225225]

Cool! Probably best to get that PR in sooner than later, there may be more bugs, but long running PRs are no fun, personally.

Your call, but I tend to avoid em.

[marcusklaas]

I am in agreement with you. I will ask Raph Levien if he has time to review when he has time.

[marcusklaas]

Merged! Thanks again for helping us get started with fuzzing :)

If you find any more, please do send em to us!