Bug during DataLoader lookups generation for `KeyValuePair<TKey, TEntity>`

[tomachristian]

graphql-platform/src/HotChocolate/Core/test/Types.Analyzers.Tests/DataLoaderTests.cs

Line 279 in b5b4f7b

public static KeyValuePair<int, Entity2> CreateLookupKey(Entity1 key)

This seems like it is working when in fact it isn't. Because it expected that the lookup delegate return a nullable KeyValuePair<TKey, TValue>. It does not come up during your tests because you are not compiling or checking the compilation errors, you're just snapshotting.

See the signature here:

public static IPromiseCacheObserver Create<TKey, TValue, TObservedValue>(
        Func<TObservedValue, KeyValuePair<TKey, TValue>?> createLookup,
        DataLoaderBase<TKey, TValue> dataLoader)
        where TKey : notnull

You have to update the source generator to expect KeyValuePair<TKey, TValue>? instead of KeyValuePair<TKey, TValue>.

cc @michaelstaib