Boolean false returned as null when FieldExtension doesn't override after_resolve (2.5.24 regression)

[aandrieu]

Describe the bug

In 2.5.24, FieldExtension#after_resolve was changed from:

def after_resolve(object:, arguments:, context:, value:, memo:)
  value
end

to:

def after_resolve(object: nil, objects: nil, arguments:, context:, values: nil, value: nil, memo:)
  value || values
end

The || operator treats false as falsy, so when a field resolver returns false, the base after_resolve evaluates false || nil → nil. This causes all Boolean fields returning false to silently become null in the response when any field extension is present (even one that doesn't override after_resolve).

Versions

graphql version: 2.5.24 (works on 2.5.23)
rails: 8.1.3
graphql-batch: 0.6.1
graphql-pro: 1.29.14

GraphQL schema

class MyExtension < GraphQL::Schema::FieldExtension
  def resolve(object:, arguments:, **_rest)
    # does something, doesn't override after_resolve
    yield(object, arguments)
  end
end

class BaseQuery < GraphQL::Schema::Resolver
  extension MyExtension
end

class IsEmptyQuery < BaseQuery
  argument :id, ID, required: true

  type Boolean, null: false

  def resolve(id:)
    record = find_record(id)
    record.children.empty? # can return false
  end
end

class QueryType < GraphQL::Schema::Object
  field :is_empty, resolver: IsEmptyQuery
end

class MySchema < GraphQL::Schema
  query QueryType
end

GraphQL query

query($id: ID!) {
  isEmpty(id: $id)
}

Expected response when the record has children:

{
  "data": {
    "isEmpty": false
  }
}

Actual response:

{
  "data": {
    "isEmpty": null
  }
}

Steps to reproduce

1. Have any FieldExtension on a field (even one that doesn't override after_resolve)
2. The field resolver returns false
3. The Interpreter calls ext.after_resolve(value: false, ...)
4. The base after_resolve evaluates false || nil → returns nil

Expected behavior

after_resolve should return false when value: false is passed

Actual behavior

after_resolve returns nil because false || values evaluates to values (which is nil).

Additional context

The fix should use nil-checking instead of ||:

def after_resolve(object: nil, objects: nil, arguments:, context:, values: nil, value: nil, memo:)
  value.nil? ? values : value
end

This was introduced in the merge of resolve / resolve_next and after_resolve / after_resolve_next into unified methods with optional keyword arguments. The old after_resolve took value: as required and simply returned it, so false was never lost.

[rmosolgo]

Thanks for the detailed report and the proposed solution. I wrote up a test and applied the patch here: #5610

I'll get it shipped later today!

[rmosolgo]

Thanks again for reporting this and sorry for the issue. I just shipped v2.5.25 which includes #5610 to fix this bug! Please let me know if it gives you any more trouble.