Compatibility with graphql ^15.0.0

[robhogan]

• Change uses of ValidationContext to use the onError constructor arg rather than the getErrors method. onError was added in 14.5.0 and made mandatory in 15.0.0, and getErrors was removed in 15.0.0.
• Remove deprecated fieldConfigEstimator and legacyFieldEstimator. These can no longer be supported due to this breaking change in graphql
• Update dev dependencies to graphql@^15.0.0 and remove @types/graphql (graphql has included its own types since 14.5.0).
• Bump peer dependency to ^14.5.0 || ^15.0.0.

Obviously this PR contains breaking changes! :)

Closes #29

[robhogan]

@ivome this might be a good time to make options.estimators required, since this PR requires changing the default estimators anyway?

[ivome]

Good idea, let's make this required now with all the breaking changes.

[robhogan]

Done

[ivome]

Do we have to drop support for 0.13 and 14.0?

[robhogan]

Sort of... The issue here is that onError was only added to the constructor args of ValidationContext in 14.5.0.

We don't strictly need that argument outside of tests, and we only pass a dummy function through anyway (since it's now mandatory), so theoretically we still have runtime compatibility with ^0.13.0 || ^14.0.0 because the extra argument we pass will simply be ignored. But, there'd be a typescript error trying to build against those versions, and the tests wouldn't work.

[robhogan]

Thanks for merging the CI PR - I've just pulled that into this branch to demonstrate the problem here - as you can see the 0.13 and 14.0 tests fail, but this is only because the tests themselves now rely on the new onError API instead of the previous getErrors.

It would be possible to fix this by adding a compatibility shim for use within tests only, which will work with any version of graphql since 0.13:

class CompatibleValidationContext extends ValidationContext {
  private errors: GraphQLError[] = []

  constructor(schema: GraphQLSchema, ast: DocumentNode, typeInfo: TypeInfo) {
    super(schema, ast, typeInfo, err => this.errors.push(err));
  }

  getErrors(): ReadonlyArray<GraphQLError> {
    // @ts-ignore
    return super.getErrors ? super.getErrors() : this.errors
  }
}

So I see three options:

1. Add (something like) the compatibility layer above for use in tests, and maintain full CI and peer support for ^0.13.0 || ^14.0.0 || ^15.0.0 at the cost of carrying a bit of legacy.
2. Remove versions below 14.5 from CI, but keep them in peer dependencies. It'll work for now, and keeps tests tidy, but you'd have to keep an eye out for regressions.
3. Bump peer dependency up to >= 14.5

Your call sir!

[ivome]

Thanks for the detailed info here! I'd say let's add this compatibility layer (just for the tests) for now with a little note to remove this once we drop support for older GraphQL versions. That should give people time to upgrade their codebases and once we drop support for the old versions, we can remove that temporary compatibility layer.

[robhogan]

Sounds good, done. I wasn't sure what to call CompatibleValidationLayer or exactly where to put it - let me know if you'd like any of that changing.

Otherwise, all tests now green, and I think we're done?

[ivome]

Thanks for adding this @rh389! I just merged this and published v0.6.0 on npm.

[robhogan]

Thanks for being so responsive, and thanks for the library 👍