Error: Cannot use GraphQLObjectType "FieldError" from another module or realm (problem and solution)

[Chriskuiper1]

Problem running 'yarn gen' after installing codegen @ 3:13 h.

src/generated/graphql.tsx
    Error: Cannot use GraphQLObjectType "FieldError" 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.

running codegen.yml

overwrite: true
schema: "http://localhost:4001/graphql"
documents: "src/graphql/**/*.graphql"
generates:
  src/generated/graphql.tsx:
    plugins:
      - "typescript"
      - "typescript-operations"
      - "typescript-urql"

I think i had conflicting packages. Removing "urql", which i think caused the problem, and reinstalling it solved the error.

yarn run v1.22.17
$ graphql-codegen --config codegen.yml
  √ Parse configuration
  √ Generate outputs

with package.json

{
    "private": true,
    "scripts": {
        "dev": "next dev",
        "build": "next build",
        "start": "next start",
        "gen": "graphql-codegen --config codegen.yml"
    },
    "dependencies": {
        "@chakra-ui/icons": "^1.0.0",
        "@chakra-ui/react": "^1.8.5",
        "@emotion/react": "^11.0.0",
        "@emotion/styled": "^11.0.0",
        "formik": "^2.2.9",
        "framer-motion": "^4.0.3",
        "next": "latest",
        "react": "^17.0.2",
        "react-dom": "^17.0.2",
        "graphql": "^16.3.0",
        "urql": "^2.2.0"
    },
    "devDependencies": {
        "@graphql-codegen/cli": "^2.6.2",
        "@graphql-codegen/typescript": "2.4.5",
        "@graphql-codegen/typescript-operations": "2.3.2",
        "@graphql-codegen/typescript-urql": "^3.5.3",
        "@graphql-codegen/urql-introspection": "^2.1.1",
        "@types/node": "^17.0.21",
        "graphql-tag": "^2.12.6",
        "typescript": "^4.5.5"
    }
}

You can edit your package.json as needed. Delete the file 'yarn.lock', 'package-lock.json' and the folder 'node_modules' to clear your dependencies. And run 'npm install' / 'yarn install' to reinstall your dependencies.