Add rkyv serialization

[Kijewski]

No description provided.

[Kijewski]

I omitted writing fuzzing tests. We would only test if rkyv can (de)serialize &strs, which would be of little use, IMO. What do you think?

[ParkMyCar]

Does this stacked borrows violation come from our code, or rkyv's?

[Kijewski]

rkyv. rust-lang/unsafe-code-guidelines#134 (comment)

Actually, I think I see what the problem is in their code. In repr.rs:40-62 they would need to replace self.inline.bytes.as_ptr() with self.inline.bytes[..].as_ptr() to make MIRI understand what is going on. If I don't forget it, I'll try if that fixes the problem.

[ParkMyCar]

I omitted writing fuzzing tests. We would only test if rkyv can (de)serialize &strs, which would be of little use, IMO. What do you think?

Not adding to the fuzzing framework is fine with me, we don't have fuzz coverage for serde either. Would you mind adding a proptest though? You could also convert the existing test if that works

[ParkMyCar]

Thanks for the PR! I haven't used rkyv myself but have definitely heard of it, and making CompactString usable with more crates is always good :)

[ParkMyCar]

I omitted writing fuzzing tests. We would only test if rkyv can (de)serialize &strs, which would be of little use, IMO. What do you think?

Not adding to the fuzzing framework is fine with me, we don't have fuzz coverage for serde either. Would you mind adding a proptest though? You could also convert the existing test if that works

@Kijewski sorry for the quick succession of comments here. Just realized we don't have any tests for serde! I'm going to add some tests now, and will add a proptest for rkyv at the same time