GraphQL-Ruby 1.12 field deprecation warnings example

deprecation_warnings.rb

require "bundler/inline"

gemfile do
  gem "graphql", "1.12.24"
end

# Newer graphql-ruby versions have `context.repsonse_extensions` which automatically
# adds data to the result["extensions"] field. But for 1.12, you have to add it manually.
# @see https://graphql-ruby.org/queries/response_extensions.html
class MySchema < GraphQL::Schema
  class DeprecatedFields < GraphQL::Analysis::AST::FieldUsage
    def result
      field_usage = super
      if field_usage[:used_deprecated_fields].any?
        # Store the warnings here for now:
        query.context[:deprecation_warnings] = field_usage[:used_deprecated_fields].map do |field_path|
          field_defn = MySchema.get_field(*field_path.split("."))
          {
            "field" => field_path,
            "deprecationReason" => field_defn.deprecation_reason,
          }
        end
      end
    end
  end

  class Query < GraphQL::Schema::Object
    field :field1, Int, null: false

    field :field2, Int, null: false, deprecation_reason: "Irrelevant"
  end

  query_analyzer(DeprecatedFields)
  query(Query)
end


result = MySchema.execute("{ field1 field2 }", root_value: { field1: 1, field2: 2 })
# Now, add the warnings to the response:
if (warnings = result.context[:deprecation_warnings])
  result["extensions"] = {
    "deprecationWarnings" => warnings
  }
end

pp result.to_h
# {
#   "data" => {
#     "field1" => 1,
#     "field2" => 2
#   },
#  "extensions" => {
#     "deprecationWarnings" => [
#       {
#         "field" => "Query.field2",
#         "deprecationReason" => "Irrelevant"
#       }
#     ]
#   }
# }