Getting multiple instances of graphql error despite only having a single version

I wasn’t sure whether or not to make a new issue or comment on https://github.com/graphql/graphql-js/issues/594 but that one is so old I figured it would be preferable to start anew

In my project I get the “ensure that there are not multiple versions of GraphQL installed in your node_modules directory” error despite having done so.

yarn list output:

yarn list --pattern graphql                   
yarn list v1.22.5
├─ @apollographql/apollo-tools@0.4.8
├─ @apollographql/graphql-playground-html@1.6.26
├─ @types/graphql-upload@8.0.4
├─ apollo-graphql@0.5.0
├─ graphql-extensions@0.12.4
├─ graphql-scalars@1.2.7
├─ graphql-tag@2.11.0
├─ graphql-tools@4.0.8
├─ graphql-upload@8.1.0
└─ graphql@15.3.0
Done in 0.87s.

and for posterity:

find node_modules -name graphql
node_modules/graphql

My tech stack includes apollo-server-lambda and nexus-schema. Not sure if/how one of them could be behind this, but the issue only cropped up after switching from apollo-server-express to apollo-server-lambda. Nevertheless, it would seem that graphql-js is reporting this error erroneously as I have proven there is only one instance of graphql in my node_modules directory.

exact error message:

Error: Cannot use GraphQLObjectType "Bio" from another module or realm.                                  
                                                                                                         
Ensure that there is only one instance of "graphql" in the node_modules                                  
directory. If different versions of "graphql" are the dependencies of other                              
relied on modules, use "resolutions" to ensure only one version is installed.                            
                                                                                                         
https://yarnpkg.com/en/docs/selective-version-resolutions                                                
                                                                                                         
Duplicate "graphql" modules cannot be used at the same time since different                              
versions may have different capabilities and behavior. The data from one                                 
version used in the function from another could produce confusing and                                    
spurious results.

Link to my project repo: https://github.com/link2cory/portfolio-backend/tree/serverless a quick note: although it is not in the current version of my repo, I have tried making use of the resolutions yarn with exactly the same results. Plus the evidence I have provided above suggests to me that it should not be necessary based on my project dependencies.

Please correct me if I am wrong in any of these assumptions!

[Nicoowr]

In our case, we put .mjs before .js in our webpack.config.js:

  resolve: {
    extensions: [".ts", ".mjs", ".json", ".js"], // IMPORTANT: .mjs has to be BEFORE .js
    plugins: [PnpWebpackPlugin],
  },

And it worked. That’s black magic.

[onhate]

@link2cory I think I finally discovered the root cause, it happens that serverless-offline uses worker threads to run the lambdas by default. Well, what that means, it means that the the lambda is instantiated in one worker thread and run in a different execution context so the Nexus schemas that are generated in the setup time uses one instance of graphql while the runtime checks after the lambda is setup uses a different instance of graphql.

By setting the following on serverless.ts it tells the serverless offline plugin that each request should run in a unique process, from setup to execution and in that case it will have the same graphql instance when nexus builds the schema and when graphql-js runs schema. This is similar to what happens in production, the same execution context is used on lambda setup and when requests are processed.

  custom: {
    'serverless-offline': {
      useChildProcesses: true
    }
  }