Internal panic in the engine

[irevoire]

Hello rhai team,

We've introduced the possibility to edit document by (rhai) function in Meilisearch a few months ago and a user reported an internal panic in rhai.
I didn’t have the time to try to reproduce the issue on my side yet, but I thought it could be nice for you to get the error with the line number in case it’s trivial to fix:

2024-09-25T07:11:29.563769Z ERROR meilisearch: info=panicked at /usr/local/cargo/registry/src/index.crates.io-6f17d22bba15001f/rhai-1.19.0/src/engine.rs:347:58: called `Option::unwrap()` on a `None` value

And here’s the original issue with the function if that helps: meilisearch/meilisearch#4956

Thanks for the awesome lib 🎉

[schungx]

This seems to happen during a strings cache contention. I can see that, under sync, there is possibility that the strings cache is still locked by another process while somebody wants to write to it.

I can remove the panic by simply cloning the string value if the cache is busy.

[schungx]

Can you check the latest drop to see if it happens again? I just pushed a fix.

[irevoire]

Hey, after a lot of tests from ourselves and our users we didn’t reproduce this bug or anything similar, thanks for the patch!

Do you think you could make a new patch release this week so we’re not relying on the git repo + a rev?

[longzou]

I encountered the same proble.
It points to this function:

pub fn get_interned_string(
    &self,
    string: impl AsRef<str> + Into<ImmutableString>,
) -> ImmutableString {
    match self.interned_strings {
        Some(ref interner) => locked_write(interner).unwrap().get(string),
        None => string.into(),
    }
}

the locked_write(interner) returns None.

[schungx]

Please kindly check out the latest drop to see if it solves your problem.

I'm planning to make a new release soonish if everything is stable.