[BUG][RUBY-NEXTGEN] Nested resources are not reachable from the client

[wiebren]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?

Description

ruby-nextgen puts nested resources in their own class (/stables/{stable}/ponies/{pony} → Api::Stables::Ponies), but the client offers no way to reach them. RubyNextgenClientCodegen#postProcessSupportingFileData computes a resources list for each namespace in rbNamespaces, but client.mustache only renders the namespace accessors, and the namespace class has no accessors either. The only way to call a nested operation is Petstore::Api::Stables::Ponies.new(client.connection).

If a namespace has only nested paths (no /stables or /stables/{stable} operation), it gets worse: Zeitwerk makes Api::Stables an implicit module from the api/stables/ directory, and the generated client.stables accessor calls Stables.new on it, which raises NoMethodError: undefined method 'new' for module Petstore::Api::Stables.

openapi-generator version

master, 7.26.0-SNAPSHOT, 05b61f34d7fb0199330e1d6c57e6159f72427837

OpenAPI declaration file content or url

openapi: 3.0.3
info:
  title: nested
  version: 1.0.0
paths:
  /stables:
    get:
      operationId: listStables
      responses:
        '200':
          description: OK
  /stables/{stable}:
    get:
      operationId: getStable
      parameters:
        - name: stable
          in: path
          required: true
          schema:
            type: string
      responses:
        '200':
          description: OK
  /stables/{stable}/ponies/{pony}:
    get:
      operationId: getPony
      parameters:
        - name: stable
          in: path
          required: true
          schema:
            type: string
        - name: pony
          in: path
          required: true
          schema:
            type: string
      responses:
        '200':
          description: OK

Generation Details

java -jar openapi-generator-cli.jar generate -g ruby-nextgen -i spec.yaml -o out \
  --additional-properties=gemName=petstore,moduleName=Petstore

This generates api/stables.rb (Stables#get, Stables#list) and api/stables/ponies.rb (Stables::Ponies#get). Generated lib/petstore/client.rb:

module Petstore
  class Client
    attr_reader :configuration, :connection

    def initialize(base_url: nil, **options, &block)
      @configuration = Configuration.new(base_url: base_url, **options, &block)
      @connection = Connection.new(@configuration)
    end

    def stables
      @stables ||= Petstore::Api::Stables.new(@connection)
    end
  end
end

Steps to reproduce

$LOAD_PATH.unshift 'out/lib'
require 'petstore'

client = Petstore::Client.new(base_url: 'http://localhost')
client.stables.ponies.get(stable: 'a', pony: 'b')

Actual (ruby 3.3):

undefined method `ponies' for an instance of Petstore::Api::Stables (NoMethodError)

Expected: client.stables.ponies returns a Petstore::Api::Stables::Ponies, matching the client.<resource>.<action> shape in the generated README.

Related issues/PRs

None found.

Suggest a fix

Render the resources that are already computed, as the crystal generator does in its client.mustache (a {{#resources}} accessor on each namespace class). The api templates are written before postProcessSupportingFileData runs, so the namespace-to-resources map has to be built earlier (e.g. from resourceSegments and the paths in preprocessOpenAPI) and passed to api.mustache for the namespace class:

      def ponies
        @ponies ||= Stables::Ponies.new(@connection)
      end

For a namespace with only nested paths, the generator must still emit a namespace class (without operations) so that client.stables has something to instantiate.

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