TypeError in 2.9.5

I am experiencing TypeError in apollo-server-express@2.9.5. I’ve not had this error in previous version and I can confirm this in PR. Starting to failing the build in circleci when upgrading the apollo packages.

Below is a log.

(node:5777) UnhandledPromiseRejectionWarning: TypeError: _schema.then is not a function
    at new ApolloServerBase (/Users/dooboolab/Github/dooboolab/hackatalk-server/node_modules/apollo-server-express/node_modules/apollo-server-core/src/ApolloServer.ts:365:40)
    at new ApolloServer (/Users/dooboolab/Github/dooboolab/hackatalk-server/node_modules/apollo-server-express/src/ApolloServer.ts:88:5)
    at Object.<anonymous> (/Users/dooboolab/Github/dooboolab/hackatalk-server/src/app.ts:43:18)
    at Generator.next (<anonymous>)
    at /Users/dooboolab/Github/dooboolab/hackatalk-server/node_modules/merge-graphql-schemas/node_modules/apollo-link/node_modules/tslib/tslib.js:107:75
    at new Promise (<anonymous>)
    at __awaiter (/Users/dooboolab/Github/dooboolab/hackatalk-server/node_modules/merge-graphql-schemas/node_modules/apollo-link/node_modules/tslib/tslib.js:103:16)
    at Object.startServer (/Users/dooboolab/Github/dooboolab/hackatalk-server/src/app.ts:27:12)
    at Object.<anonymous> (/Users/dooboolab/Github/dooboolab/hackatalk-server/src/server.ts:3:1)
    at Module._compile (internal/modules/cjs/loader.js:936:30)
    at Module.m._compile (/Users/dooboolab/Github/dooboolab/hackatalk-server/node_modules/ts-node/src/index.ts:493:23)
    at Module._extensions..js (internal/modules/cjs/loader.js:947:10)
    at Object.require.extensions.<computed> [as .ts] (/Users/dooboolab/Github/dooboolab/hackatalk-server/node_modules/ts-node/src/index.ts:496:12)
    at Module.load (internal/modules/cjs/loader.js:790:32)
    at Function.Module._load (internal/modules/cjs/loader.js:703:12)
    at Function.Module.runMain (internal/modules/cjs/loader.js:999:10)
    at Object.<anonymous> (/Users/dooboolab/Github/dooboolab/hackatalk-server/node_modules/ts-node/src/bin.ts:158:12)
    at Module._compile (internal/modules/cjs/loader.js:936:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:947:10)
    at Module.load (internal/modules/cjs/loader.js:790:32)
    at Function.Module._load (internal/modules/cjs/loader.js:703:12)
    at Function.Module.runMain (internal/modules/cjs/loader.js:999:10)

–>

[henry-young]

Perhaps there could be better type checking and error messaging. In the offending code, apollo server assumes that if it isn’t a GraphQLSchema then it is a promise of GraphQLSchema.

// apollo-core/ApolloServer.ts - Line 365
    if (_schema instanceof GraphQLSchema) {
      const derivedData = this.generateSchemaDerivedData(_schema);
      this.schema = derivedData.schema;
      this.schemaDerivedData = Promise.resolve(derivedData);
    } else {
      this.schemaDerivedData = _schema.then(schema =>
        this.generateSchemaDerivedData(schema),
      );
    }

Potentially a fix could be to convert non-promise schemas to a promise, resolve that schema promise, then type check the schema against GraphQLSchema.

I’ve also seen other projects (e.g. class-validator) warn of multiple versions of the library in node_modules, although this case would be a concern for the graphql library.

[henry-young]

@hyochan I was also experiencing this error. I found that this issue was caused by different npm modules using conflicting versions of graphql. My fix included using yarn resolutions to set the version of graphql that your modules will use.

Snippet from my package.json

{
  ...
  "dependencies":{
    "graphql": "^14.5.8"
    ...
  },
  "resolutions": {
    "type-graphql/**/graphql": "^14.5.8"
  }
}