How to define a nullable list with non-nullable items in a GraphQL schema using HotChocolate?-CodePudding

I'm using C# 10 but with nullable reference types disabled on .NET 6 and HotChocolate 12.12.0.

My Query.cs has an entry like this:

public async Task<List<Foo>> GetFoos() { ... }

The generated GraphQL schema looks like this: foos: [Foo] (nullable array with nullable Foo-items)

When I add the [GraphQLNonNullType] attribute to the GetFoos() method, the generated GraphQL schema looks like this: foos: [Foo!]! (non-nullable array with non-nullable Foo-items)

What I want my schema to look like is this: foos: [Foo!] (nullable array with non-nullable Foo-items)

From what I've found (e.g. this answer) this should be possible somehow.

Does HotChocolate provide any way to produce a nullable array with non-nullable items in the schema?

CodePudding user response：

One solution is to enable nullable reference types and then explicitly mark the list as nullable.

Enable nullable reference types in the .csproj file:

<Nullable>enable</Nullable>

public async Task<List<Foo>?> GetFoos() { ... }

To not change this setting for the whole project (as this likely breaks stuff), the nullable directives can be used to enable this feature just in certain parts of your code:

#nullable enable
public async Task<List<Foo>?> GetFoos() { ... }
#nullable disable

Don't forget to disable it again, otherwise it will also affect any other code below.

While this solves my problem for now, I would still be interested if there is a solution without enabling nullable reference types.

CodePudding user response：

Yes, this is possible using Hot Chocolate.

Using annotation-based approach:

[GraphQLType(typeof(ListType<NonNullType<ObjectType<Foo>>>))]
public async Task<List<Foo>> GetFoos() { ... }

Using code-first approach:

descriptor
    .Field("foos")
    .Type<ListType<NonNullType<ObjectType<Foo>>>>();

https://chillicream.com/docs/hotchocolate/defining-a-schema/non-null/#explicit-nullability