2.0 - Update cache after a mutation

[Vincz]

Question

Hi guys,

I'm trying to migrate my project to the new API.
My use case is quite simple.
I call a mutation that add an object, then I want to add this object to a list in the cache so I don't have to request the complete list again.

Here is my code converted:

func addList(name: String) async throws -> String? {      
        guard let data = try await mutation(mutation: CreateListMutation(name: name)) else { return nil }
        let newList = data.list

        try await apollo.store.withinReadWriteTransaction { transaction in
            let cacheMutation = ListsLocalCacheMutation()
            try await transaction.update(cacheMutation) { (data: inout ListsLocalCacheMutation.Data) in
                let list = ListsLocalCacheMutation.Data.List(_dataDict: newList.__data)
                data.lists.append(newList)
            }
        } 
    }

So, before the update I was creating an ListsLocalCacheMutation.Data.List object from the data of a CreateListMutation.Data.List object.
I'm not even sure that was the proper way but it worked.
Now, I can't access the __data property anymore cause I get the error '__data' is inaccessible due to '@_spi' protection level

What would be the new and proper way to handle this? Do I have the choice or do I need to recreate manually by resettings all the properties one by one, with something like that:

let list = ListsLocaleCacheMutation.Data.List(name: newList.name, etc....)

Thanks

[AnthonyMDev]

Thanks for the question @Vincz. It would be a good idea for us to generate convenience initializers for converting from the mutation types to the query types, but it's not high priority, so I wouldn't expect us to add this anytime soon.

There are a number of ways you can address this right now though!

The first would be what you guessed, which is manually recreating the objects and passing all the properties over. Which will work, but is obviously very cumbersome.

The second is that you can still use the old way of accessing the unsafe DataDict. You would just need to import the SPI by adding the import statement in this file: @_spi(Unsafe) import ApolloAPI. But the reason why we put this behind an SPI is because it's inherently unsafe so it's also not really recommended.

The way that I would handle this right now is to use shared fragment. If you define a GraphQL fragment and use that fragment in both your CreateListMutation and ListsLocalCacheMutation, then the fragment type can be used across both operations and you should be able to just append the objects to the list.

Let us know if that doesn't work out for you for any reason!

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