Apollo-tooling: Support for "extend type" when using local graphql schema

[matthewerwin]

v0.16.2 (or earlier) doesn't properly generate the JSON when "extend type" is used. Only the definition without the extended properties is written out to the json file. We use "extend type" for apollo-server to allow the types to exist across different files but not throw IDE errors.

An example case:

type Query {
version:String
}

type Mutation {
}

extend type Query {
#get a user
userExists(id:ID) : Boolean
}

schema {
query: Query
mutation: Mutation
}

Apollo-codegen will not provide the "userExists" definition in the Query type it generates to JSON. Only the "version" property will be scripted.

[matthewerwin]

Related to this it should be possible to run an introspection like:

apollo-codegen introspect-schema ./*/.graphqls --output ./schema.json

With "extend type" in some of the files and the actual type specified in another file without getting the following error "Must provide schema definition with query type or a type named Query."

i.e. One manner to handle that may be to use loadAndMergeQueryDocuments similar to the "apollo-codegen generate" CLI command rather than assuming that the full document is in a single file.

[rricard]

@matthewerwin You should open a second issue to track the related issue you saw. I think there is some discussion necessary on that second one. (the main issue you reported here is definitely a bug we want to fix)

[matthewerwin]

@rricard per my comments on #211 I have a fix already in place for this. Will see if I can get everything pulled together for review by your team quickly after testing. I can issue a PR separately for the bug since the other additions involve a lot more code.

For my sub-comment above it was just a matter of switching to "glob" when isMagic()=true and using the loadAndMergeQueryDocuments( ) to splice everything together just like generate does with the inputPaths. I then called extendSchema( ) from graphql library the same way it's done by their team to get the proper AST and works for both introspect-schema and generate.

[matthewerwin]

https://github.com/apollographql/apollo-codegen/pull/217

[mike-marcacci]

This should definitely be supported, since extend is part of the SDL spec.

[nilshartmann]

This would be also very useful for type extensions on the client using apollo-link-state.

Currently it seems to be impossible to use apollo-codegen for Queries that use types like this:

// TypeDef on the Client
// (Person is a Type that's also contained in the Server's schema)

const typeDefs = `
  extend type Person {
    fullName: String!
  }
`

(Note than on the client schema you just can leave out the extend but that's semantically not 100% correct I think)

[aishwar]

Curious, why was this issue closed? This issue still seems to be present.

[Xample]

As a workaround, I remove the extend keyword prior to merging the schema using merge-graphql-schemas I then use only the merged schema one…

import { fileLoader, mergeTypes } from 'merge-graphql-schemas';
import { writeFileSync } from 'fs';

const loadedFiles = fileLoader(`${process.cwd()}/src/**/*.graphql`);
const withoutExtendFiles = loadedFiles.map((schema) => schema.replace(/extend *type/g, 'type'));
const typeDefs = mergeTypes(withoutExtendFiles, { all: true });
writeFileSync('./generated/merged.schema.graphql', typeDefs);

[craigsmitham]

FWIW, we did not have the same issue working with https://github.com/dotansimha/graphql-code-generator, which we've starting using recently partly due to this issue.