[Bug] Mount point has effect on mounted API class

[bogdan]

If I mount UsersAPI under /v1 namespace, this namespace gets propagated into the mounted class.
This causes a problem if same class is mounted more than once.

Reproduce:

# frozen_string_literal: true

require 'bundler/inline'

gemfile(true) do
  source 'https://rubygems.org'
  gem 'grape'
  gem 'rack'
  gem 'minitest'
  gem 'rack-test'
end

require 'minitest/autorun'
require 'rack/test'
require 'grape'

class GrapeAPIBugTest < Minitest::Test
  include Rack::Test::Methods

  class UsersAPI < Grape::API
    format :json

    get "/users" do
      present :users, []
    end
  end

  class RootAPI < Grape::API
    format :json

    namespace "/v1" do
      mount UsersAPI
    end
  end

  def test_nested_route_via_root_api
    env = Rack::MockRequest.env_for("/v1/users")
    status, _, body = RootAPI.call(env)

    assert_equal '{"users":[]}', body.join
    assert_equal 200, status
  end

  def test_direct_users_api
    env = Rack::MockRequest.env_for("/users")
    status, _, body = UsersAPI.call(env)

    assert_equal '{"users":[]}', body.join
    assert_equal 200, status
  end
end

[ericproulx]

I'll check that. Thanks for opening the issue

[ericproulx]

I do confirm and somehow the way classes are declared (at least in RSpec) is changing the outcome.

The works outside namespace will fail when declared like this

describe '#issue 2576' do
  UsersAPI = Class.new(Grape::API) do
    format :json

    get "/users" do
      present :users, []
    end
  end

  RootAPI = Class.new(Grape::API) do
    format :json

    namespace "/v1" do
      mount UsersAPI
    end
  end

  it 'works with namespace' do
    env = Rack::MockRequest.env_for("/v1/users", method: Rack::GET)
    result = Rack::MockResponse[*RootAPI.call(env)]
    expect(result.status).to eq(200)
    expect(result.body).to eq('{"users":[]}')
  end

  it 'works outside namespace' do
    env = Rack::MockRequest.env_for("/users", method: Rack::GET)
    result = Rack::MockResponse[*users_api.call(env)]
    expect(result.status).to eq(200)
    expect(result.body).to eq('{"users":[]}')
  end
end

This version does not

describe '#issue 2576' do
  let(:users_api) do
    Class.new(Grape::API) do
      format :json

      get "/users" do
        present :users, []
      end
    end
  end

  let(:root_api) do
    api_to_mount = users_api
    Class.new(Grape::API) do
      format :json

      namespace "/v1" do
        mount api_to_mount
      end
    end
  end

  it 'works with namespace' do
    env = Rack::MockRequest.env_for("/v1/users", method: Rack::GET)
    result = Rack::MockResponse[*root_api.call(env)]
    expect(result.status).to eq(200)
    expect(result.body).to eq('{"users":[]}')
  end

  it 'works outside namespace' do
    env = Rack::MockRequest.env_for("/users", method: Rack::GET)
    result = Rack::MockResponse[*users_api.call(env)]
    expect(result.status).to eq(200)
    expect(result.body).to eq('{"users":[]}')
  end
end

[ericproulx]

I've been testing earlier versions (too 1.5.3) and they all failed the test. I don't know how's your setup but doing the following works

# frozen_string_literal: true

require 'bundler/inline'

gemfile(true) do
  source 'https://rubygems.org'
  gem 'grape'
  gem 'rack'
  gem 'minitest'
  gem 'rack-test'
end

require 'minitest/autorun'
require 'rack/test'
require 'grape'

class GrapeAPIBugTest < Minitest::Test
  include Rack::Test::Methods

  UsersAPI = Class.new(Grape::API) do
    format :json

    get "/users" do
      present :users, []
    end
  end

  RootAPI = Class.new(Grape::API) do
    format :json

    namespace "/v1" do
      mount UsersAPI
    end

    namespace "/v2" do
      mount UsersAPI
    end

    mount UsersAPI
  end

  def test_v1_users_via_api
    env = Rack::MockRequest.env_for("/v1/users", method: Rack::GET)
    status, _, body = RootAPI.call(env)

    assert_equal '{"users":[]}', body.join
    assert_equal 200, status
  end

  def test_v2_users_via_root_api
    env = Rack::MockRequest.env_for("/v2/users", method: Rack::GET)
    status, _, body = RootAPI.call(env)

    assert_equal '{"users":[]}', body.join
    assert_equal 200, status
  end

  def test_users_via_root_api
    env = Rack::MockRequest.env_for("/users", method: Rack::GET)
    status, _, body = RootAPI.call(env)

    assert_equal '{"users":[]}', body.join
    assert_equal 200, status
  end
end

Passing by the RootAPI always works even when mounted under different namespaces.

[bogdan]

Passing by the RootAPI always works even when mounted under different namespaces.

Well, I think it is not the reason we shouldn't fix it. Testing particular API object in isolate can have performance benefit as well as just feels right.

[ericproulx]

You're absolutly right. I was just suggesting an alternative and I was searching if it was a regression between versions. I'll take some time this weekend to understand it.