Panic on write to nested Vec in a Store

[purung]

Describe the bug
I tried using a nested <For> with a Store. However, when I write to the inner Vec I get a wasm panic in the browser.

I think this would be the same as if I had a Vec<Tag> on a Todo, and tried using outer.inner().write().push(new) as in the stores example to extend the Tag list.

Leptos Dependencies

Starter axum template, 0.7 + reactive_stores, nightly.

Minimal example: https://github.com/purung/stores_inner_error

Expected behavior
I am sure I am missing something, but I would have expected this to work since stores are about ergonomics with nested structure, and I used methods shown in the example. Or, a compiler error.

Error output

storestest.wasm:2808272:1
    ha14370bbf30ccd11 http://localhost:3000/pkg/storestest.wasm:2808272
    h95b597a01bd9daef http://localhost:3000/pkg/storestest.wasm:945930
    h552e73743194e10d http://localhost:3000/pkg/storestest.wasm:2473618
    ha062b0945442f7c0 http://localhost:3000/pkg/storestest.wasm:449903
    storestest.wasm.<reactive_stores::keyed::AtKeyed<Inner,Prev,K,T> as reactive_stores::store_field::StoreField>::reader::h455912315912b83c http://localhost:3000/pkg/storestest.wasm:858638
    storestest.wasm.<reactive_stores::arc_field::ArcField<<T as core::ops::index::Index<usize>>::Output> as core::convert::From<reactive_stores::keyed::AtKeyed<Inner,Prev,K,T>>>::from::{{closure}}::hf9f0c381b0482ab7 http://localhost:3000/pkg/storestest.wasm:2394984
    storestest.wasm.<reactive_stores::arc_field::ArcField<T> as reactive_stores::store_field::StoreField>::reader::hfeffe2d13c428f77 http://localhost:3000/pkg/storestest.wasm:2179627
    storestest.wasm.<reactive_stores::field::Field<T,S> as reactive_stores::store_field::StoreField>::reader::{{closure}}::he2fab88640fe124a http://localhost:3000/pkg/storestest.wasm:2588176
    h9329b9d965df7527 http://localhost:3000/pkg/storestest.wasm:1782641
    storestest.wasm.<reactive_stores::field::Field<T,S> as reactive_stores::store_field::StoreField>::reader::hb757e29258931c78 http://localhost:3000/pkg/storestest.wasm:2250249
    storestest.wasm.<reactive_stores::keyed::KeyedSubfield<Inner,Prev,K,T> as reactive_stores::store_field::StoreField>::reader::h678049d17d4a97f4 http://localhost:3000/pkg/storestest.wasm:1630721

[gbj]

I have not looked into this fully yet.

However, something occurs to me right away: You are generating UUIDs as keys, and you start with items in both the Outer and Inner structures. However, you're also using SSR + hydration, which means that the code runs on both sides. As a result, you are generating different UUIDs: the data in the list is different on the server from the client.

Like I said, I have no idea if this is related and I have not tried running the example, it just occurs to me as I look at the code.

[purung]

A very reasonable question, and my first thought was that the Uuids might have had something to do with it. I did, however, observe the error with fixed usize as well. I just happened to settle on uuid in this example. It's closer to my use case, which you can see it in a help thread on discord if you like. Thanks for looking into it when you have time 😊

[gbj]

Having played around for an hour or so this evening, I do think that there is simply an issue with nested keyed fields at the moment. I will try to find some time to look at it in more depth in the upcoming weeks.

[purung]

I appreciate the time you put in to making this work, when you have it to spare 🙏

[gbj]

As is so often the case, sleeping on it for a night and coming back to it made all the difference. #3344 should fix this issue: I tested it against your example and it seems to work correctly but let me know if that's not the case.

[purung]

That's fantastic! I haven't managed to test it in my project yet, but the minimal example should suffice to be confident.