fix(mergeSchemas): Prevent custom resolvers from being overwritten by default resolvers

[mattkrick]

Description

custom resolvers should overwrite default resolvers

Related #4367

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

1. Do a merge schema, which will give every field a default resolver
2. Do a merge schema again with custom resolvers
3. Notice the custom resolver is being used (below you should see '42' in the console)

const mySchema = mergeSchemas(...) // this will add a default resolver to every field
const withNestedSchema = mergeSchemas({
  schemas: [mySchema],
  resolvers: {_extQuery: { projects: () => console.log(42); return 42}} // this resolver gets overwritten during merge!
})

[changeset-bot]

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[borisno2]

Hey @mattkrick just looking at the PR, it looks like it hasn't been touched in a while, is this something you are still working on?

@ardatan if this passes tests is this something you would be happy to merge?

I am happy to help get this one over the line if required. It would help us with an issue we are having over at KeystoneJS keystonejs/keystone#7527

Thanks!

[borisno2]

Using the following here, resolved the type errors in the tests for me

 const resolvers = config.resolvers || [];
  for (const resolver of asArray(resolvers)) {
    extractedResolvers.push(resolver);
  }

[ardatan]

Instead of the change above, we can basically change this push tounshift

[borisno2]

Hi @ardatan
Yes, this looks to work from my testing today...

I don't have access to make this change, @mattkrick is this a change you are able to make?

@ardatan if @mattkrick is not able to do this, is this something you are able to push, or would you like me to create a new PR with this change and the changeset?

Thanks!

[ardatan]

We'd love to accept a new PR :)

[borisno2]

Thanks @ardatan - I have created #4455

[ardatan]

I'm afraid this can be a breaking change for the existing users relying on this behavior.
So is it possible to make sure we won't have regressions later?
And also could you add a changeset with yarn changeset?

[ardatan]

Closed in favor of #4455