Internal error creating checkout

[dlallie]

I am trying to create a basic checkout from a single product ID to then hand off to the browser with the web URL. The graph mutation task however returns an invalid query error with an "Internal error" reason.

One of my request IDs from this error is: 009b1e52-0a89-4918-aa10-5dc5314282e1

Below is the code I am using with version 3.7.0 of the SDK:

let checkout = Storefront.CheckoutCreateInput.create(
    lineItems: .value([
        Storefront.CheckoutLineItemInput.create(quantity: 1, variantId: GraphQL.ID(rawValue: "Z2lkOi8vc2hvcGlmeS9Qcm9kdWN0LzQ1MzM4NTg1OTg5ODY="))
    ])
)

let mutation = Storefront.buildMutation { $0
    .checkoutCreate(input: checkout) { $0
        .checkout { $0
            .webUrl()
        }
    }
}

let task = client.mutateGraphWith(mutation) { result, error in
    ...
}
task.resume()

[dlallie]

I found that this issue was caused by inputing a product ID in the GraphQL.ID initialiser. When using the correct variant ID for a product (even one with no variants) creating checkouts is now working as expected.