apollo service：push返回错误：未知类型：“用户”，但是在本地运行良好。如何解决这个谜？

Question

原始代码来自此处：https://github.com/apollographql/federation-demo/blob/master/services/reviews/index.js

我的代码是这样的：

const typeDefs = gql`

  extend type User @key(fields: "id") {
    id: ID! @external
    numberOfReviews: Int
    reviews: [Review]
  }

  type Review @key(fields: "id") {
    id: ID!
    body: String
    author: User 
    product: Product
  }

  extend type Product @key(fields: "upc") {
    upc: String! @external
    reviews: [Review]
  }
`;

const resolvers = {
  Review: {
    author(review) {
      // Review.author -> provides the field `username` and requires User.username to be marked as @external.
      console.log("review service returning author")
      return { __typename: "User", id: review.authorID };
    }
  },
  User: {
    reviews(user, _args, { dataSources }) {
      console.log("review service returning reviews for user " + user.id)
      return reviews.filter(review => review.authorID === user.id);
    },
    numberOfReviews(user, _args, { dataSources }) {
      console.log("review service returning numberOfReviews for user " + user.id)
      return reviews.filter(review => review.authorID === user.id).length;
    }
  },
  Product: {
    reviews(product, _args, { dataSources }) {
      console.log("review service returning reviews for product " + product.upc)
      return reviews.filter(review => review.product.upc === product.upc);
    }
  }
};

我有其他非常相似的服务，它们可以毫无问题地解析类型。

我该怎么做才能解决这个错误？

Fetching info from federated service
  ✔ Loading Apollo Project
  ✔ Loading Apollo Project
  ✖ Uploading service to Engine
    → Unknown type: "User".
Error: Unknown type: "User".