Apollo GraphQL Error: Query root type must be provided - graphql

Question

I have an Angular/Apollo GraphQL implementation generating typescript code based on GraphQl endpoint which is surfacing a schema. I can hit the endpoint via Postman with a query and results are returned. However, when I run "graphql-codegen --config codegen.yml" via npm I get this error:
"Error: Query root type must be provided"
The server side is .Net Core implementation using GraphQL ASPNetCore. I have 4 different queries defined and each one works via graphiql.
Any ideas on why query root type is now being returned as null?

Answer 1

GraphQL must have at least one #Query() to be considered valid. So maybe only need add any Query to your Resolver code will be helpful.
Ex:
export class FooResolver {
#Query(() => String)
sayHello(): string {
return 'Hello World!';
}
}

Answer 2

This error throws when your schema stiching/definitions are incorrect. Please check the check your root schema definitions
https://www.advancedgraphql.com/content/schema-stitching

Answer 3

I was having the same issue while using graphql-codegen.
my codegen.yml is
overwrite: true
schema: "http://localhost:3001/graphql"
documents: "src/app/graphql/*.graphql"
generates:
src/generated/graphql.ts:
plugins:
- typescript
- typescript-operations
- typescript-apollo-angular
The issue was coming when I used the plugin typescript-apollo-angular.
I'm using Nodejs with graphql as backend.
The issue got resolved when I renamed the type
RootQuery -> Query
and
RootMutation -> Mutation
in backend schema.
Before
type RootQuery {
_empty: String
}
type RootMutation {
_empty: String
}
schema {
query: RootQuery
mutation: RootMutation
}
After
type Query {
_empty: String
}
type Mutation {
_empty: String
}
schema {
query: Query
mutation: Mutation
}

Answer 4

I ended up reverting back to a previous version of the codebase and reapplied my modifications manually and it works now. The only thing I can think of is I ran npm update which updated apollo-angular from 1.8.3 to 1.10.0.
EDIT Here is my code:
codegen.yml (used to generate code from npm command):
overwrite: true
schema: "https://to_end_point/Prod/api/v1/GraphQL"
documents: "src/**/*.graphql"
generates:
src/generated/graphql.ts:
plugins:
- "typescript"
- "typescript-operations"
- "typescript-apollo-angular"
./graphql.schema.json:
plugins:
- "introspection"
After reverting back to a previous version of Angular code then re-applying my code modifications, GraphQl code generation worked again. The only thing I can think of which could have caused this issue was when I ran npm update. Below is a screenshot of before/after of package.json: