fix: no data duplication in reactive Set/Map

[Azarattum]

Svelte 5 rewrite

Data in reactive Set/Map was unnecessarily passed back to the super class. That would mean storing the same thing twice. This PR addresses this problem and adds a couple of tests to ensure the implementation is correct.

We have discussed this earlier on Discord: https://discord.com/channels/457912077277855764/1153350350158450758/1227898085087248434, where @trueadm suggested I made a PR.

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[trueadm]

Thanks for this!

[harrisi]

This breaks Set prototype methods that are added to the ReactiveSet prototype dynamically. See also #11222.

[paoloricciuti]

I was trying to see how #11222 could be fixed without reintroducing data duplication but unless we want to reimplement each one of the methods by hand we need the data in the "faux" Set since we are invoking methods on it.

The simple fix would be to revert this and introduce data duplication again.

[harrisi]

Yes, all methods need to be implemented. The problem with that is that it will also break if the prototypes of any of the builtins are changed.

[Azarattum]

I'll take look at this. We do already redefine the methods in #init. I think there has to be a way to adapt this without reintroducing data duplication.

[paoloricciuti]

I'll take look at this. We do already redefine the methods in #init. I think there has to be a way to adapt this without reintroducing data duplication.

The point is that that's exactly the bug: in init we are redefining the methods to actually call super.methodname in the set instance but since that instance has no values they are empty.

We could reimplement those methods but that adds code to maintain, probably less performant code in those operations (since is not native) and no forward compatibility for a small memory gain.

[paoloricciuti]

I'll take look at this. We do already redefine the methods in #init. I think there has to be a way to adapt this without reintroducing data duplication.

The point is that that's exactly the bug: in init we are redefining the methods to actually call super.methodname in the set instance but since that instance has no values they are empty.

We could reimplement those methods but that adds code to maintain, probably less performant code in those operations (since is not native) and no forward compatibility for a small memory gain.

But obviously feel free to try and report back if you succeed 😁

[Azarattum]

Yeah, I get that. I feel like there is a way to use native implementation without duplication. Also this is only applicable to Set, right? The Map isn't affected (since it doesn't have those methods). Which means we don't have to revert the entire PR in the worst case.

By the way, I think map not having those methods is actually the main issue here. Since we currently model set with map keys and there are no such methods for map keys. Maybe we can find a different approach to model the data?

[paoloricciuti]

Yeah, I get that. I feel like there is a way to use native implementation without duplication. Also this is only applicable to Set, right? The Map isn't affected (since it doesn't have those methods). Which means we don't have to revert the entire PR in the worst case.

By the way, I think map not having those methods is actually the main issue here. Since we currently model set with map keys and there are no such methods for map keys. Maybe we can find a different approach to model the data?

I've to investigate a bit further as I didn't check if Map was also "duplicating data". I guess if you can find a way to use the data inside Set that could work. Let's think about it