Problem integrating connection types and dataloader for paginated (cursor) queries

Hi, I'm using the latest version of this library with dataloader-sequelize@2.1.2.

After upgrading dataloader-sequelize to v>=2.0 the batching basically stopped working until I readjusted my field resolvers to follow the example in this PR: https://github.com/mickhansen/graphql-sequelize/pull/671

This has solved the issue for fields which have model/association resolvers, i. e.:

resolve: (...args) => resolver(User.Roles, { separate: false })(...args)

The above example works. However, I have issues getting it work with connections. Here is a connection I have created:

const PostConnection = createConnection({
  name: 'PostConnection',
  nodeType: PostType,
  target: Channel.Posts,
  connectionFields: {
    total: {
      type: GraphQLInt,
      resolve: ({ source }) => source.countPosts()
    }
  },
  edgeFields: {}
});

And here is the postsConnection resolver for Channel type:

        postsConnection: {
          type: PostConnection.connectionType,
          args: PostConnection.connectionArgs,
          resolve: (...args) => PostConnection.resolve(...args)
        },

This does go through the Dataloader - I can see that posts are being fetched. The query also works properly the first time it is run, when the cursor (after in connection args) argument equals to empty string:

query Channels {
  channels {
    id
    postsConnection(first: 10, after: "") {
      edges {
        node {
          id
          name
        }
      }
    }
  }
}

The problem appears when after argument is not empty:

query Channels {
  channels {
    id
    postsConnection(first: 10, after: "WyIwNTU0YTZjMS01MDRmLTQ3N2ItODM2My1lYzI4YjVhOTAxZmYiLDld") {
      edges {
        node {
          id
          name
        }
      }
    }
  }
}

When I want to load 10 more results, a database error is thrown: SequelizeDatabaseError: argument of LIMIT must be type bigint, not type integer[]

And it is related to this part of the generated query:

(...)
ORDER BY "subquery_order_0" DESC LIMIT ARRAY[10,10] OFFSET 10) AS sub) AS "Post" ORDER BY "subquery_order_0" DESC;

When I change back postsConnection resolver to:

resolve: PostConnection.resolve

the pagination works, but dataloader doesn't. I end up with an extremely slow execution time.

Note: Channel and Post have many-to-many relation.

At first I thought it was due to dataloader-sequelize being updated to v2 but after I'd downgraded it to v1.7 (and reverted my changes to field resolvers) I end up with a working dataloader but broken pagination for Connections, so the end result is the same.

I found a closed issue with similar problem: https://github.com/mickhansen/graphql-sequelize/issues/673 but the cause seems to be different because I don't use Connection for channels?

mickhansen / graphql-sequelize

Problem integrating connection types and dataloader for paginated (cursor) queries #695