Bump version to 0.10.10

Include namespace when looking up superclass

.rubocop.yml

@@ -59,6 +59,10 @@ Style/MissingElse:
 Style/EmptyElse:
   EnforcedStyle: empty
 
+Style/FrozenStringLiteralComment:
+  Enabled: true
+  EnforcedStyle: always
+
 Style/MultilineOperationIndentation:
   EnforcedStyle: indented
 

.travis.yml

@@ -1,55 +1,104 @@
 language: ruby
-
 sudo: false
 
-rvm:
+ruby_supported_versions:
-  - 2.1
+  - &ruby_2_1 2.1.10
-  - 2.2.6
+  - &ruby_2_2 2.2.10
-  - 2.3.3
+  - &ruby_2_3 2.3.8
-  - ruby-head
+  - &ruby_2_4 2.4.6
-  - jruby-9.1.5.0 # is precompiled per http://rubies.travis-ci.org/
+  - &ruby_2_5 2.5.5
-  - jruby-head
+  - &ruby_2_6 2.6.3
+  - &ruby_head ruby-head
 
-jdk:
+rails_supported_versions:
-  - oraclejdk8
+  - &rails_4_1 RAILS_VERSION=4.1
+  - &rails_4_2 RAILS_VERSION=4.2
+  - &rails_5_0 RAILS_VERSION=5.0
+  - &rails_5_1 RAILS_VERSION=5.1
+  - &rails_5_2 RAILS_VERSION=5.2
+  - &rails_6_0_0_rc1 RAILS_VERSION=6.0.0.rc1
+  - &rails_master RAILS_VERSION=master
 
-before_install:
-  - gem update --system
-  - rvm @global do gem uninstall bundler -a -x
-  - rvm @global do gem install bundler -v 1.13.7
-install: bundle install --path=vendor/bundle --retry=3 --jobs=3
 cache:
   directories:
     - vendor/bundle
 
+before_install:
+  - "travis_retry gem update --system 2.7.9"
+  - "travis_retry gem install bundler -v '1.17.3'"
+install: BUNDLER_VERSION=1.17.3 bundle install --path=vendor/bundle --retry=3 --jobs=3
+
 script:
   - bundle exec rake ci
 after_success:
   - codeclimate-test-reporter
+
 env:
-  global:
-    - "JRUBY_OPTS='--dev -J-Xmx1024M --debug'"
   matrix:
-    - "RAILS_VERSION=4.1"
+    - *rails_4_1
-    - "RAILS_VERSION=4.2"
+    - *rails_4_2
-    - "RAILS_VERSION=5.0"
+    - *rails_5_0
-    - "RAILS_VERSION=master"
+    - *rails_5_1
+    - *rails_5_2
+    - *rails_6_0_0_rc1
+    - *rails_master
+
+rvm:
+  - *ruby_2_1
+  - *ruby_2_2
+  - *ruby_2_3
+  - *ruby_2_4
+  - *ruby_2_5
+  - *ruby_2_6
+  - *ruby_head
+
+branches:
+  only: 0-10-stable
 
 matrix:
+  include:
+    - { rvm: jruby-9.1.13.0, jdk: oraclejdk8, env: "RAILS_VERSION=4.1 JRUBY_OPTS='--dev -J-Xmx1024M --debug'" }
+    - { rvm: jruby-9.1.13.0, jdk: oraclejdk8, env: "RAILS_VERSION=4.2 JRUBY_OPTS='--dev -J-Xmx1024M --debug'" }
+    - { rvm: jruby-9.1.13.0, jdk: oraclejdk8, env: "RAILS_VERSION=5.1 JRUBY_OPTS='--dev -J-Xmx1024M --debug'" }
+    # See JRuby currently failing on Rails 5+ https://github.com/jruby/activerecord-jdbc-adapter/issues/708
+    # - { rvm: jruby-9.1.13.0, jdk: oraclejdk8, env: "RAILS_VERSION=5.0 JRUBY_OPTS='--dev -J-Xmx1024M --debug'" }
+    # - { rvm: jruby-head,     jdk: oraclejdk8, env: "RAILS_VERSION=5.1 JRUBY_OPTS='--dev -J-Xmx1024M --debug'" }
   exclude:
-  - rvm: 2.1
+    - { rvm: *ruby_2_1,  env: *rails_5_0 }
-    env: RAILS_VERSION=master
+    - { rvm: *ruby_2_1,  env: *rails_5_1 }
-  - rvm: jruby-9.1.5.0
+    - { rvm: *ruby_2_1,  env: *rails_5_2 }
-    env: RAILS_VERSION=master
+
-  - rvm: jruby-head
+    - { rvm: *ruby_2_1,  env: *rails_6_0_0_rc1 }
-    env: RAILS_VERSION=master
+    - { rvm: *ruby_2_2,  env: *rails_6_0_0_rc1 }
-  - rvm: 2.1
+    - { rvm: *ruby_2_3,  env: *rails_6_0_0_rc1 }
-    env: RAILS_VERSION=5.0
+    - { rvm: *ruby_2_4,  env: *rails_6_0_0_rc1 }
-  - rvm: jruby-9.1.5.0
+
-    env: RAILS_VERSION=5.0
+    - { rvm: *ruby_2_1,  env: *rails_master }
-  - rvm: jruby-head
+    - { rvm: *ruby_2_2,  env: *rails_master }
-    env: RAILS_VERSION=5.0
+    - { rvm: *ruby_2_3,  env: *rails_master }
+    - { rvm: *ruby_2_4,  env: *rails_master }
+
   allow_failures:
-    - rvm: ruby-head
+    - { rvm: *ruby_2_4,  env: *rails_4_1 }
+    - { rvm: *ruby_2_5,  env: *rails_4_1 }
+    - { rvm: *ruby_2_6,  env: *rails_4_1 }
+
+    # allow RAILS_VERSION=master to fail against ruby 2.5+ until this gem supports RAILS_VERSION
+    # https://github.com/rails/rails/blob/master/RAILS_VERSION
+    # https://github.com/rails-api/active_model_serializers/blob/0-10-stable/active_model_serializers.gemspec#L24
+    - { rvm: *ruby_2_5,  env: *rails_master }
+    - { rvm: *ruby_2_6,  env: *rails_master }
+
+    - rvm: *ruby_head
+    # - { rvm: *ruby_head, env: *rails_4_1 }
+    # - { rvm: *ruby_head, env: *rails_4_2 }
+    # - { rvm: *ruby_head, env: *rails_5_0 }
+    # - { rvm: *ruby_head, env: *rails_5_1 }
+    # - { rvm: *ruby_head, env: *rails_5_2 }
+    # - { rvm: *ruby_head, env: *rails_6_0_0_rc1 }
+    # - { rvm: *ruby_head, env: *rails_master }
+
     - rvm: jruby-head
+    # See JRuby currently failing on Rails 5+ https://github.com/jruby/activerecord-jdbc-adapter/issues/708
+    - { rvm: jruby-9.1.13.0, jdk: oraclejdk8, env: "RAILS_VERSION=5.1 JRUBY_OPTS='--dev -J-Xmx1024M --debug'" }
   fast_finish: true

CHANGELOG.md

@@ -1,6 +1,6 @@
 ## 0.10.x
 
-### [master (unreleased)](https://github.com/rails-api/active_model_serializers/compare/v0.10.6...master)
+### [master (unreleased)](https://github.com/rails-api/active_model_serializers/compare/v0.10.10...0-10-stable)
 
 Breaking changes:
 
@@ -10,6 +10,96 @@ Fixes:
 
 Misc:
 
+### [v0.10.10 (2019-07-13)](https://github.com/rails-api/active_model_serializers/compare/v0.10.9...v0.10.10)
+
+Fixes:
+
+- [#2319](https://github.com/rails-api/active_model_serializers/pull/2319) Fixes #2316. (@kylekeesling)
+    - Fix Rails 6.0 deprication warnings
+    - update test fixture schema to use `timestamps` instead of `timestamp`
+- [#2223](https://github.com/rails-api/active_model_serializers/pull/2223) Support Fieldset in Attributes/JSON adapters documented in [docs/general/fields.md](https://github.com/rails-api/active_model_serializers/blob/0-10-stable/docs/general/fields.md) that worked partially before (@bf4)
+- [#2337](https://github.com/rails-api/active_model_serializers/pull/2337) fix incorrect belongs_to serialization when foreign_key on object and belongs_to is blank (@InteNs)
+    - Fixes incorrect json-api generation when `jsonapi_use_foreign_key_on_belongs_to_relationship` is `true` and the relationship is blank
+- [#2172](https://github.com/rails-api/active_model_serializers/pull/2172) Preserve the namespace when falling back to a superclass serializer
+
+Misc:
+
+- [#2327](https://github.com/rails-api/active_model_serializers/pull/2327) Add support for Ruby 2.6 on Travis CI (@wasifhossain)
+- [#2304](https://github.com/rails-api/active_model_serializers/pull/2304) Slim down bundled gem by excluding test files and docs (@greysteil)
+
+### [v0.10.9 (2019-02-08)](https://github.com/rails-api/active_model_serializers/compare/v0.10.8...v0.10.9)
+
+Fixes:
+
+- [#2288](https://github.com/rails-api/active_model_serializers/pull/2288)
+  Change the fetch method to deal with recyclable key cache strategy.
+  Fixes #2287. (@cintamani, @wasifhossain)
+- [#2307](https://github.com/rails-api/active_model_serializers/pull/2307) Falsey attribute values should not be reevaluated.
+
+Misc:
+
+- [#2309](https://github.com/rails-api/active_model_serializers/pull/2309) Performance and memory usage fixes
+
+### [v0.10.8 (2018-11-01)](https://github.com/rails-api/active_model_serializers/compare/v0.10.7...v0.10.8)
+
+Features:
+- [#2279](https://github.com/rails-api/active_model_serializers/pull/2279) Support condition options in serializer link statements
+
+Fixes:
+
+- [#2296](https://github.com/rails-api/active_model_serializers/pull/2296) Fixes #2295 (@Hirurg103)
+  - Fix finding of namespaced serializer and non-namespaced model.
+- [#2289](https://github.com/rails-api/active_model_serializers/pull/2289) Fixes #2255 (@f-mer)
+  - Fix autoloading race condition, especially in Rails 5.
+- [#2299](https://github.com/rails-api/active_model_serializers/pull/2299) Fixes #2270 (@chau-bao-long via #2276)
+  - Fix reflection thread-safety bug
+
+### [v0.10.7 (2017-11-14)](https://github.com/rails-api/active_model_serializers/compare/v0.10.6...v0.10.7)
+
+Regressions Fixed From v0.10.6:
+
+- [#2211](https://github.com/rails-api/active_model_serializers/pull/2211). Fixes #2125, #2160. (@bf4)
+  - Fix polymorphic belongs_to tests; passes on v0.10.5, fails on v0.10.6
+  - Fix JSON:API polymorphic type regression from v0.10.5
+  - Fix JSON:API: for_type_and_id should always inflect_type
+      ```
+      Should Serializer._type ever be inflected?
+      Right now, it won't be, but association.serializer._type will be inflected.
+
+      That's the current behavior.
+       ```
+- [#2216](https://github.com/rails-api/active_model_serializers/pull/2216). Fixes #2132, #2180. (@bf4)
+  - Fix JSON:API: Serialize resource type for unpersisted records (blank id)
+- [#2218](https://github.com/rails-api/active_model_serializers/pull/2218). Fixes #2178. (@bf4)
+  - Fix JSON:API: Make using foreign key on belongs_to opt-in. No effect on polymorphic relationships.
+      ```
+        # set to true to opt-in
+        ActiveModelSerializer.config.jsonapi_use_foreign_key_on_belongs_to_relationship = true
+      ```
+
+Features:
+
+- [#2136](https://github.com/rails-api/active_model_serializers/pull/2136) Enable inclusion of sideloaded relationship objects by `key`. (@caomania)
+- [#2021](https://github.com/rails-api/active_model_serializers/pull/2021) ActiveModelSerializers::Model#attributes. Originally in [#1982](https://github.com/rails-api/active_model_serializers/pull/1982). (@bf4)
+- [#2130](https://github.com/rails-api/active_model_serializers/pull/2130) Allow serialized ID to be overwritten for belongs-to relationships. (@greysteil)
+- [#2189](https://github.com/rails-api/active_model_serializers/pull/2189)
+  Update version constraint for jsonapi-renderer to `['>= 0.1.1.beta1', '< 0.3']`
+  (@tagliala)
+
+Fixes:
+
+- [#2022](https://github.com/rails-api/active_model_serializers/pull/2022) Mutation of ActiveModelSerializers::Model now changes the attributes. Originally in [#1984](https://github.com/rails-api/active_model_serializers/pull/1984). (@bf4)
+- [#2200](https://github.com/rails-api/active_model_serializers/pull/2200) Fix deserialization of polymorphic relationships. (@dennis95stumm)
+- [#2214](https://github.com/rails-api/active_model_serializers/pull/2214) Fail if unable to infer collection type with json adapter. (@jmeredith16)
+- [#2149](https://github.com/rails-api/active_model_serializers/pull/2149) Always include self, first, last pagination link. (@mecampbellsoup)
+- [#2179](https://github.com/rails-api/active_model_serializers/pull/2179) Fixes #2173, Pass block to Enumerator.new. (@drn)
+
+Misc:
+
+- [#2176](https://github.com/rails-api/active_model_serializers/pull/2176) Documentation for global adapter config. (@mrpinsky)
+- [#2215](https://github.com/rails-api/active_model_serializers/pull/2215) Update `serializers.md` documentation to denote alternate use cases for `scope`. (@stratigos)
+- [#2212](https://github.com/rails-api/active_model_serializers/pull/2212) Remove legacy has_many_embed_ids test. (@bf4)
+
 ### [v0.10.6 (2017-05-01)](https://github.com/rails-api/active_model_serializers/compare/v0.10.5...v0.10.6)
 
 Fixes:

Gemfile

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 source 'https://rubygems.org'
 #
 # Add a Gemfile.local to locally bundle gems outside of version control
@@ -12,6 +14,7 @@ version = ENV['RAILS_VERSION'] || '4.2'
 if version == 'master'
   gem 'rack', github: 'rack/rack'
   gem 'arel', github: 'rails/arel'
+  gem 'rails', github: 'rails/rails'
   git 'https://github.com/rails/rails.git' do
     gem 'railties'
     gem 'activesupport'
@@ -23,6 +26,7 @@ if version == 'master'
   end
 else
   gem_version = "~> #{version}.0"
+  gem 'rails', gem_version
   gem 'railties', gem_version
   gem 'activesupport', gem_version
   gem 'activemodel', gem_version
@@ -36,18 +40,38 @@ end
 # Windows does not include zoneinfo files, so bundle the tzinfo-data gem
 gem 'tzinfo-data', platforms: (@windows_platforms + [:jruby])
 
+if ENV['CI']
+  if RUBY_VERSION < '2.4'
+    # Windows: An error occurred while installing nokogiri (1.8.0)
+    gem 'nokogiri', '< 1.7', platforms: @windows_platforms
+  end
+end
+
 group :bench do
   # https://github.com/rails-api/active_model_serializers/commit/cb4459580a6f4f37f629bf3185a5224c8624ca76
   gem 'benchmark-ips', '>= 2.7.2', require: false, group: :development
 end
 
 group :test do
-  gem 'sqlite3',                          platform: (@windows_platforms + [:ruby])
+  platforms(*(@windows_platforms + [:ruby])) do
-  gem 'activerecord-jdbcsqlite3-adapter', platform: :jruby
+    if version == 'master' || version >= '6'
+      gem 'sqlite3', '~> 1.4'
+    else
+      gem 'sqlite3', '~> 1.3.13'
+    end
+  end
+  platforms :jruby do
+    if version == 'master' || version >= '5'
+      gem 'activerecord-jdbcsqlite3-adapter', '~> 50'
+    else
+      gem 'activerecord-jdbcsqlite3-adapter', '~> 1.3.0'
+    end
+  end
   gem 'codeclimate-test-reporter', require: false
   gem 'm', '~> 1.5'
-  gem 'pry', '~> 0.10'
+  gem 'pry', '>= 0.10'
-  gem 'pry-byebug', '~> 3.4', platform: :ruby
+  gem 'byebug', '~> 8.2' if RUBY_VERSION < '2.2'
+  gem 'pry-byebug', platforms: :ruby
 end
 
 group :development, :test do

README.md

@@ -49,8 +49,6 @@ Check how to change the adapter in the sections below.
 `0.10.x` is based on the `0.8.0` code, but with a more flexible
 architecture. We'd love your help. [Learn how you can help here.](CONTRIBUTING.md)
 
-It is generally safe and recommended to use the master branch.
-
 ## Installation
 
 Add this line to your application's Gemfile:
@@ -187,7 +185,7 @@ and, if there is no serializer, primitives.
 
 ### ActiveModelSerializers::Adapter::Base
 
-The **`ActiveModelSerializeres::Adapter::Base`** describes the structure of the JSON document generated from a
+The **`ActiveModelSerializers::Adapter::Base`** describes the structure of the JSON document generated from a
 serializer. For example, the `Attributes` example represents each serializer as its
 unmodified attributes.  The `JsonApi` adapter represents the serializer as a [JSON
 API](http://jsonapi.org/) document.
@@ -268,8 +266,8 @@ to know about, but not part of ActiveModelSerializers.)
 
 - An `ActiveRecord::Base` object.
 - Any Ruby object that passes the
-  [Lint](http://www.rubydoc.info/github/rails-api/active_model_serializers/ActiveModel/Serializer/Lint/Tests)
+  [Lint](https://www.rubydoc.info/gems/active_model_serializers/ActiveModel/Serializer/Lint/Tests)
-  [code](https://github.com/rails-api/active_model_serializers/blob/master/lib/active_model/serializer/lint.rb).
+  [(code)](lib/active_model/serializer/lint.rb).
 
 ActiveModelSerializers provides a
 [`ActiveModelSerializers::Model`](https://github.com/rails-api/active_model_serializers/blob/master/lib/active_model_serializers/model.rb),

Rakefile

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 begin
   require 'bundler/setup'
 rescue LoadError

active_model_serializers.gemspec

@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 # coding: utf-8
 lib = File.expand_path('../lib', __FILE__)
 $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
@@ -14,14 +15,13 @@ Gem::Specification.new do |spec|
   spec.homepage      = 'https://github.com/rails-api/active_model_serializers'
   spec.license       = 'MIT'
 
-  spec.files         = `git ls-files -z`.split("\x0")
+  spec.files         = Dir["CHANGELOG.md", "MIT-LICENSE", "README.md", "lib/**/*"]
-  spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ['lib']
   spec.executables   = []
 
   spec.required_ruby_version = '>= 2.1'
 
-  rails_versions = ['>= 4.1', '< 6']
+  rails_versions = ['>= 4.1', '< 6.1']
   spec.add_runtime_dependency 'activemodel', rails_versions
   # 'activesupport', rails_versions
   # 'builder'
@@ -39,10 +39,10 @@ Gem::Specification.new do |spec|
   # 'activesupport', rails_versions
   # 'i18n,
   # 'tzinfo'
-  # 'minitest'
+  spec.add_development_dependency 'minitest', ['~> 5.0', '< 5.11']
   # 'thread_safe'
 
-  spec.add_runtime_dependency 'jsonapi-renderer', ['>= 0.1.1.beta1', '< 0.2']
+  spec.add_runtime_dependency 'jsonapi-renderer', ['>= 0.1.1.beta1', '< 0.3']
   spec.add_runtime_dependency 'case_transform', '>= 0.2'
 
   spec.add_development_dependency 'activerecord', rails_versions

appveyor.yml

@@ -4,20 +4,22 @@ skip_tags: true
 
 environment:
   JRUBY_OPTS: "--dev -J-Xmx1024M --debug"
+  RAILS_VERSION: 5.2
   matrix:
-    - ruby_version: "Ruby21"
+    - ruby_version: "Ruby23"
-    - ruby_version: "Ruby21-x64"
+    - ruby_version: "Ruby23-x64"
 
 cache:
   - vendor/bundle
 
 install:
   - SET PATH=C:\%ruby_version%\bin;%PATH%
-  - gem update --system
+  - gem uninstall bundler -a -x -I
-  - gem uninstall bundler -a -x
+  - gem update --system 2.7.9
-  - gem install bundler -v 1.13.7
+  - # gem install bundler -v '1.17.3'
   - bundle env
-  - bundle install --path=vendor/bundle --retry=3 --jobs=3
+  - bundle check || bundle install --path=vendor/bundle --retry=3 --jobs=3
+  - bundle clean --force
 
 before_test:
   - ruby -v

docs/general/adapters.md

@@ -36,6 +36,12 @@ The `Attributes` adapter does not include a root key. It is just the serialized
 
 Use either the `JSON` or `JSON API` adapters if you want the response document to have a root key.
 
+***IMPORTANT***: Adapter configuration has *no effect* on a serializer instance
+being used directly. That is, `UserSerializer.new(user).as_json` will *always*
+behave as if the adapter were the 'Attributes' adapter. See [Outside Controller
+Usage](../howto/outside_controller_use.md) for more details on recommended
+usage.
+
 ## Built in Adapters
 
 ### Attributes - Default

docs/general/configuration_options.md

@@ -57,6 +57,7 @@ still prefer the render option `:key_transform` over this setting.
 application, setting `config.key_transform` to `:unaltered` will provide a performance boost.*
 
 ##### default_includes
+
 What relationships to serialize by default.  Default: `'*'`, which includes one level of related
 objects. See [includes](adapters.md#included) for more info.
 
@@ -162,6 +163,21 @@ Default: `{}`.
 
 *Used when `jsonapi_include_toplevel_object` is `true`*
 
+##### jsonapi_use_foreign_key_on_belongs_to_relationship
+
+When true, the relationship will determine its resource object identifier
+without calling the association or its serializer.  This can be useful when calling
+the association object is triggering unnecessary queries.
+
+For example, if a `comment` belongs to a `post`, and the comment
+uses the foreign key `post_id`, we can determine the resource object
+identifier `id` as `comment.post_id` and the `type` from the association options.
+Or quite simply, it behaves as `belongs_to :post, type: :posts, foreign_key: :post_id`.
+
+Note: This option has *no effect* on polymorphic associations as we cannot reliably
+determine the associated object's type without instantiating it.
+
+Default: `false`.
 
 ## Hooks
 

docs/general/rendering.md

@@ -290,4 +290,4 @@ See [Usage outside of a controller](../howto/outside_controller_use.md#serializi
 
 ## Pagination
 
-See [How to add pagination links](https://github.com/rails-api/active_model_serializers/blob/master/docs/howto/add_pagination_links.md).
+See [How to add pagination links](../howto/add_pagination_links.md).

docs/general/serializers.md

@@ -65,7 +65,7 @@ Where:
   - `virtual_value:`
   - `polymorphic:` defines if polymorphic relation type should be nested in serialized association.
   - `type:` the resource type as used by JSON:API, especially on a `belongs_to` relationship.
-  - `class_name:` used to determine `type` when `type` not given
+  - `class_name:` the (String) model name used to determine `type`, when `type` is not given. e.g. `class_name: "Comment"` would imply the type `comments`
   - `foreign_key:` used by JSON:API on a `belongs_to` relationship to avoid unnecessarily loading the association object.
   - `namespace:` used when looking up the serializer and `serializer` is not given.  Falls back to the parent serializer's `:namespace` instance options, which, when present, comes from the render options. See [Rendering#namespace](rendering.md#namespace] for more details.
 - optional: `&block` is a context that returns the association's attributes.
@@ -81,6 +81,7 @@ e.g.
 ```ruby
 has_one :bio
 has_one :blog, key: :site
+has_one :blog, class_name: "Blog"
 has_one :maker, virtual_value: { id: 1 }
 
 has_one :blog do |serializer|
@@ -114,6 +115,7 @@ e.g.
 has_many :comments
 has_many :comments, key: :reviews
 has_many :comments, serializer: CommentPreviewSerializer
+has_many :comments, class_name: "Comment"
 has_many :reviews, virtual_value: [{ id: 1 }, { id: 2 }]
 has_many :comments, key: :last_comments do
   last(1)
@@ -127,6 +129,7 @@ e.g.
 ```ruby
 belongs_to :author, serializer: AuthorPreviewSerializer
 belongs_to :author, key: :writer
+belongs_to :author, class_name: "Author"
 belongs_to :post
 belongs_to :blog
 def blog
@@ -235,6 +238,15 @@ link :other, 'https://example.com/resource'
 link(:posts) { link_author_posts_url(object) }
 ```
 
+Just like attributes, links also support conditions in options
+```ruby
+link(:secret, if: :internal?) { object.secret_link }
+
+def internal?
+  instance_options[:context] == :internal
+end
+```
+
 #### #object
 
 The object being serialized.
@@ -294,6 +306,8 @@ end
 Whether you write the method as above or as `object.comments.where(created_by: scope)`
 is a matter of preference (assuming `scope_name` has been set).
 
+Keep in mind that the scope can be set to any available controller reference. This can be utilized to provide access to any other data scopes or presentation helpers.
+
 ##### Controller Authorization Context
 
 In the controller, the scope/scope_name options are equal to
@@ -311,7 +325,7 @@ current authorization scope when you call `render :json`.
 called on every request.  This was [also a problem](https://github.com/rails-api/active_model_serializers/pull/1252#issuecomment-159810477)
 in [`0.9`](https://github.com/rails-api/active_model_serializers/tree/0-9-stable#customizing-scope).
 
-We can change the scope from `current_user` to `view_context`.
+We can change the scope from `current_user` to `view_context`, which is included in subclasses of `ActionController::Base`.
 
 ```diff
 class SomeController < ActionController::Base
@@ -379,6 +393,7 @@ class PostsController < ActionController::Base
   end
 end
 ```
+Note that any controller reference which provides the desired scope is acceptable, such as another controller method for loading a different resource or reference to helpers. For example, `ActionController::API` does not include `ActionView::ViewContext`, and would need a different reference for passing any helpers into a serializer via `serialization_scope`.
 
 #### #read_attribute_for_serialization(key)
 
@@ -437,7 +452,7 @@ serializer classes.
 
 ## More Info
 
-For more information, see [the Serializer class on GitHub](https://github.com/rails-api/active_model_serializers/blob/master/lib/active_model/serializer.rb)
+For more information, see [the Serializer class on GitHub](https://github.com/rails-api/active_model_serializers/blob/0-10-stable/lib/active_model/serializer.rb)
 
 ## Overriding association methods
 
@@ -471,7 +486,7 @@ the `ActiveModel::Serializer.serializer_for` method to return a serializer class
 ```ruby
 class MySerializer < ActiveModel::Serializer
   def self.serializer_for(model, options)
-    return SparseAdminSerializer if model.class == 'Admin'
+    return SparseAdminSerializer if model.class.name == 'Admin'
     super
   end
 

docs/howto/add_root_key.md

@@ -18,6 +18,13 @@ In order to add the root key you need to use the ```JSON``` Adapter, you can cha
 ActiveModelSerializers.config.adapter = :json
 ```
 
+Note that adapter configuration has no effect on a serializer that is called
+directly, e.g. in a serializer unit test. Instead, something like
+`UserSerializer.new(user).as_json` will *always* behave as if the adapter were
+the 'Attributes' adapter. See [Outside Controller
+Usage](../howto/outside_controller_use.md) for more details on recommended
+usage.
+
 You can also specify a class as adapter, as long as it complies with the ActiveModelSerializers adapters interface.
 It will add the root key to all your serialized endpoints.
 

lib/action_controller/serialization.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_support/core_ext/class/attribute'
 require 'active_model_serializers/serialization_context'
 
@@ -21,7 +23,15 @@ module ActionController
     end
 
     def namespace_for_serializer
-      @namespace_for_serializer ||= self.class.parent unless self.class.parent == Object
+      @namespace_for_serializer ||= namespace_for_class(self.class) unless namespace_for_class(self.class) == Object
+    end
+
+    def namespace_for_class(klass)
+      if Module.method_defined?(:module_parent)
+        klass.module_parent
+      else
+        klass.parent
+      end
     end
 
     def serialization_scope

lib/active_model/serializable_resource.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'set'
 
 module ActiveModel

lib/active_model/serializer.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'thread_safe'
 require 'jsonapi/include_directive'
 require 'active_model/serializer/collection_serializer'
@@ -18,16 +20,17 @@ module ActiveModel
     # @see #serializable_hash for more details on these valid keys.
     SERIALIZABLE_HASH_VALID_KEYS = [:only, :except, :methods, :include, :root].freeze
     extend ActiveSupport::Autoload
+    eager_autoload do
       autoload :Adapter
       autoload :Null
       autoload :Attribute
+      autoload :Link
       autoload :Association
       autoload :Reflection
-    autoload :SingularReflection
-    autoload :CollectionReflection
       autoload :BelongsToReflection
       autoload :HasOneReflection
       autoload :HasManyReflection
+    end
     include ActiveSupport::Configurable
     include Caching
 
@@ -91,7 +94,7 @@ module ActiveModel
         if serializer_class
           serializer_class
         elsif klass.superclass
-          get_serializer_for(klass.superclass)
+          get_serializer_for(klass.superclass, namespace)
         else
           nil # No serializer found
         end
@@ -142,6 +145,7 @@ module ActiveModel
     # Make JSON API top-level jsonapi member opt-in
     # ref: http://jsonapi.org/format/#document-top-level
     config.jsonapi_include_toplevel_object = false
+    config.jsonapi_use_foreign_key_on_belongs_to_relationship = false
     config.include_data_default = true
 
     # For configuring how serializers are found.
@@ -274,9 +278,14 @@ module ActiveModel
     #   link(:self) { "http://example.com/resource/#{object.id}" }
     # @example
     #   link :resource, "http://example.com/resource"
+    # @example
+    #   link(:callback, if: :internal?), { "http://example.com/callback" }
     #
-    def self.link(name, value = nil, &block)
+    def self.link(name, *args, &block)
-      _links[name] = block || value
+      options = args.extract_options!
+      # For compatibility with the use case of passing link directly as string argument
+      # without block, we are creating a wrapping block
+      _links[name] = Link.new(name, options, block || ->(_serializer) { args.first })
     end
 
     # Set the JSON API meta attribute of a serializer.
@@ -337,10 +346,10 @@ module ActiveModel
     # @return [Enumerator<Association>]
     def associations(include_directive = ActiveModelSerializers.default_include_directive, include_slice = nil)
       include_slice ||= include_directive
-      return Enumerator.new unless object
+      return Enumerator.new {} unless object
 
       Enumerator.new do |y|
-        self.class._reflections.each do |key, reflection|
+        (self.instance_reflections ||= self.class._reflections.deep_dup).each do |key, reflection|
           next if reflection.excluded?(self)
           next unless include_directive.key?(key)
 
@@ -356,6 +365,9 @@ module ActiveModel
     def serializable_hash(adapter_options = nil, options = {}, adapter_instance = self.class.serialization_adapter_instance)
       adapter_options ||= {}
       options[:include_directive] ||= ActiveModel::Serializer.include_directive_from_options(adapter_options)
+      if (fieldset = adapter_options[:fieldset])
+        options[:fields] = fieldset.fields_for(json_key)
+      end
       resource = attributes_hash(adapter_options, options, adapter_instance)
       relationships = associations_hash(adapter_options, options, adapter_instance)
       resource.merge(relationships)
@@ -370,7 +382,12 @@ module ActiveModel
 
     # Used by adapter as resource root.
     def json_key
-      root || _type || object.class.model_name.to_s.underscore
+      root || _type ||
+        begin
+          object.class.model_name.to_s.underscore
+        rescue ArgumentError
+          'anonymous_object'
+        end
     end
 
     def read_attribute_for_serialization(attr)
@@ -404,6 +421,6 @@ module ActiveModel
 
     protected
 
-    attr_accessor :instance_options
+    attr_accessor :instance_options, :instance_reflections
   end
 end

lib/active_model/serializer/adapter.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_model_serializers/adapter'
 require 'active_model_serializers/deprecate'
 

lib/active_model/serializer/adapter/attributes.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     module Adapter

lib/active_model/serializer/adapter/base.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     module Adapter

lib/active_model/serializer/adapter/json.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     module Adapter

lib/active_model/serializer/adapter/json_api.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     module Adapter

lib/active_model/serializer/adapter/null.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     module Adapter

lib/active_model/serializer/array_serializer.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_model/serializer/collection_serializer'
 
 module ActiveModel

lib/active_model/serializer/association.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_model/serializer/lazy_association'
 
 module ActiveModel

lib/active_model/serializer/attribute.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_model/serializer/field'
 
 module ActiveModel

lib/active_model/serializer/belongs_to_reflection.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     # @api private

lib/active_model/serializer/collection_serializer.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     class CollectionSerializer
@@ -19,11 +21,10 @@ module ActiveModel
 
       # @api private
       def serializable_hash(adapter_options, options, adapter_instance)
-        include_directive = ActiveModel::Serializer.include_directive_from_options(adapter_options)
+        options[:include_directive] ||= ActiveModel::Serializer.include_directive_from_options(adapter_options)
-        adapter_options[:cached_attributes] ||= ActiveModel::Serializer.cache_read_multi(self, adapter_instance, include_directive)
+        options[:cached_attributes] ||= ActiveModel::Serializer.cache_read_multi(self, adapter_instance, options[:include_directive])
-        adapter_opts = adapter_options.merge(include_directive: include_directive)
         serializers.map do |serializer|
-          serializer.serializable_hash(adapter_opts, options, adapter_instance)
+          serializer.serializable_hash(adapter_options, options, adapter_instance)
         end
       end
 
@@ -46,7 +47,9 @@ module ActiveModel
         # 3. get from collection name, if a named collection
         key ||= object.respond_to?(:name) ? object.name && object.name.underscore : nil
         # 4. key may be nil for empty collection and no serializer option
-        key && key.pluralize
+        key &&= key.pluralize
+        # 5. fail if the key cannot be determined
+        key || fail(ArgumentError, 'Cannot infer root key from collection type. Please specify the root or each_serializer option, or render a JSON String')
       end
       # rubocop:enable Metrics/CyclomaticComplexity
 

lib/active_model/serializer/concerns/caching.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     UndefinedCacheKey = Class.new(StandardError)
@@ -281,7 +283,9 @@ module ActiveModel
       # Use object's cache_key if available, else derive a key from the object
       # Pass the `key` option to the `cache` declaration or override this method to customize the cache key
       def object_cache_key
-        if object.respond_to?(:cache_key)
+        if object.respond_to?(:cache_key_with_version)
+          object.cache_key_with_version
+        elsif object.respond_to?(:cache_key)
           object.cache_key
         elsif (serializer_cache_key = (serializer_class._cache_key || serializer_class._cache_options[:key]))
           object_time_safe = object.updated_at

lib/active_model/serializer/error_serializer.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     class ErrorSerializer < ActiveModel::Serializer

lib/active_model/serializer/errors_serializer.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_model/serializer/error_serializer'
 
 module ActiveModel

lib/active_model/serializer/field.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     # Holds all the meta-data about a field (i.e. attribute or association) as it was

lib/active_model/serializer/fieldset.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     class Fieldset

lib/active_model/serializer/has_many_reflection.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     # @api private

lib/active_model/serializer/has_one_reflection.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     # @api private

lib/active_model/serializer/lazy_association.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     # @api private
@@ -7,11 +9,12 @@ module ActiveModel
       delegate :collection?, to: :reflection
 
       def reflection_options
-        @reflection_options ||= reflection.options.dup.reject { |k, _| !REFLECTION_OPTIONS.include?(k) }
+        @reflection_options ||= reflection.options.select { |k, _| REFLECTION_OPTIONS.include?(k) }
       end
 
       def object
-        @object ||= reflection.value(
+        return @object if defined?(@object)
+        @object = reflection.value(
           association_options.fetch(:parent_serializer),
           association_options.fetch(:include_slice)
         )
@@ -76,6 +79,7 @@ module ActiveModel
         serializer_options[:serializer_context_class] = association_options.fetch(:parent_serializer).class
         serializer = reflection_options.fetch(:serializer, nil)
         serializer_options[:serializer] = serializer if serializer
+        serializer_options[:namespace]  = reflection_options[:namespace] if reflection_options[:namespace]
         serializer_class.new(object, serializer_options)
       end
 

lib/active_model/serializer/link.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+require 'active_model/serializer/field'
+
+module ActiveModel
+  class Serializer
+    # Holds all the data about a serializer link
+    #
+    # @example
+    #   class PostSerializer < ActiveModel::Serializer
+    #     link :callback, if: :internal? do
+    #       object.callback_link
+    #     end
+    #
+    #     def internal?
+    #       instance_options[:internal] == true
+    #     end
+    #   end
+    #
+    class Link < Field
+    end
+  end
+end

lib/active_model/serializer/lint.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     module Lint

lib/active_model/serializer/null.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
     class Null < Serializer

lib/active_model/serializer/reflection.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_model/serializer/field'
 require 'active_model/serializer/association'
 
@@ -140,7 +142,7 @@ module ActiveModel
       def include_data?(include_slice)
         include_data_setting = options[:include_data_setting]
         case include_data_setting
-        when :if_sideloaded then include_slice.key?(name)
+        when :if_sideloaded then include_slice.key?(options.fetch(:key, name))
         when true           then true
         when false          then false
         else fail ArgumentError, "Unknown include_data_setting '#{include_data_setting.inspect}'"
@@ -151,6 +153,9 @@ module ActiveModel
       # @yield [ActiveModel::Serializer]
       # @return [:nil, associated resource or resource collection]
       def value(serializer, include_slice)
+        # NOTE(BF): This method isn't thread-safe because the _reflections class attribute is not thread-safe
+        # Therefore, when we build associations from reflections, we dup the entire reflection instance.
+        # Better solutions much appreciated!
         @object = serializer.object
         @scope = serializer.scope
 

lib/active_model/serializer/version.rb

@@ -1,5 +1,7 @@
+# frozen_string_literal: true
+
 module ActiveModel
   class Serializer
-    VERSION = '0.10.6'.freeze
+    VERSION = '0.10.10'.freeze
   end
 end

lib/active_model_serializers.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_model'
 require 'active_support'
 require 'active_support/core_ext/object/with_options'
@@ -5,16 +7,19 @@ require 'active_support/core_ext/string/inflections'
 require 'active_support/json'
 module ActiveModelSerializers
   extend ActiveSupport::Autoload
+  eager_autoload do
     autoload :Model
     autoload :Callbacks
-  autoload :Deserialization
     autoload :SerializableResource
+    autoload :SerializationContext
     autoload :Logging
     autoload :Test
     autoload :Adapter
     autoload :JsonPointer
     autoload :Deprecate
     autoload :LookupChain
+    autoload :Deserialization
+  end
 
   class << self; attr_accessor :logger; end
   self.logger = ActiveSupport::TaggedLogging.new(ActiveSupport::Logger.new(STDOUT))
@@ -46,8 +51,13 @@ module ActiveModelSerializers
     $VERBOSE = original_verbose
   end
 
+  def self.eager_load!
+    super
+    ActiveModel::Serializer.eager_load!
+  end
+
   require 'active_model/serializer/version'
   require 'active_model/serializer'
   require 'active_model/serializable_resource'
-  require 'active_model_serializers/railtie' if defined?(::Rails)
+  require 'active_model_serializers/railtie' if defined?(::Rails::Railtie)
 end

lib/active_model_serializers/adapter.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Adapter
     UnknownAdapterError = Class.new(ArgumentError)
@@ -35,7 +37,7 @@ module ActiveModelSerializers
 
       # @return [Array<Symbol>] list of adapter names
       def adapters
-        adapter_map.keys.sort
+        adapter_map.keys.sort!
       end
 
       # Adds an adapter 'klass' with 'name' to the 'adapter_map'

lib/active_model_serializers/adapter/attributes.rb

@@ -1,6 +1,13 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Adapter
     class Attributes < Base
+      def initialize(*)
+        super
+        instance_options[:fieldset] ||= ActiveModel::Serializer::Fieldset.new(fields_to_fieldset(instance_options.delete(:fields)))
+      end
+
       def serializable_hash(options = nil)
         options = serialization_options(options)
         options[:fields] ||= instance_options[:fields]
@@ -8,6 +15,22 @@ module ActiveModelSerializers
 
         self.class.transform_key_casing!(serialized_hash, instance_options)
       end
+
+      private
+
+      def fields_to_fieldset(fields)
+        return fields if fields.nil?
+        resource_fields = []
+        relationship_fields = {}
+        fields.each do |field|
+          case field
+          when Symbol, String then resource_fields << field
+          when Hash then relationship_fields.merge!(field)
+          else fail ArgumentError, "Unknown conversion of fields to fieldset: '#{field.inspect}' in '#{fields.inspect}'"
+          end
+        end
+        relationship_fields.merge!(serializer.json_key.to_sym => resource_fields)
+      end
     end
   end
 end

lib/active_model_serializers/adapter/base.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'case_transform'
 
 module ActiveModelSerializers

lib/active_model_serializers/adapter/json.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Adapter
     class Json < Base

lib/active_model_serializers/adapter/json_api.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # {http://jsonapi.org/format/ JSON API specification}
 # rubocop:disable Style/AsciiComments
 # TODO: implement!
@@ -22,14 +24,16 @@ module ActiveModelSerializers
   module Adapter
     class JsonApi < Base
       extend ActiveSupport::Autoload
+      eager_autoload do
         autoload :Jsonapi
         autoload :ResourceIdentifier
-      autoload :Relationship
         autoload :Link
         autoload :PaginationLinks
         autoload :Meta
         autoload :Error
         autoload :Deserialization
+        autoload :Relationship
+      end
 
       def self.default_key_transform
         :dash
@@ -480,7 +484,8 @@ module ActiveModelSerializers
       #   }.reject! {|_,v| v.nil? }
       def links_for(serializer)
         serializer._links.each_with_object({}) do |(name, value), hash|
-          result = Link.new(serializer, value).as_json
+          next if value.excluded?(serializer)
+          result = Link.new(serializer, value.block).as_json
           hash[name] = result if result
         end
       end

lib/active_model_serializers/adapter/json_api/deserialization.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Adapter
     class JsonApi
@@ -189,7 +191,7 @@ module ActiveModelSerializers
 
           polymorphic = (options[:polymorphic] || []).include?(assoc_name.to_sym)
           if polymorphic
-            hash["#{prefix_key}_type".to_sym] = assoc_data.present? ? assoc_data['type'] : nil
+            hash["#{prefix_key}_type".to_sym] = assoc_data.present? ? assoc_data['type'].classify : nil
           end
 
           hash

lib/active_model_serializers/adapter/json_api/error.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Adapter
     class JsonApi < Base

lib/active_model_serializers/adapter/json_api/jsonapi.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Adapter
     class JsonApi < Base

lib/active_model_serializers/adapter/json_api/link.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Adapter
     class JsonApi

lib/active_model_serializers/adapter/json_api/meta.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Adapter
     class JsonApi

lib/active_model_serializers/adapter/json_api/pagination_links.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Adapter
     class JsonApi < Base
@@ -20,12 +22,13 @@ module ActiveModelSerializers
         end
 
         def as_json
-          per_page = collection.try(:per_page) || collection.try(:limit_value) || collection.size
+          {
-          pages_from.each_with_object({}) do |(key, value), hash|
+            self:  location_url,
-            params = query_parameters.merge(page: { number: value, size: per_page }).to_query
+            first: first_page_url,
-
+            prev:  prev_page_url,
-            hash[key] = "#{url(adapter_options)}?#{params}"
+            next:  next_page_url,
-          end
+            last:  last_page_url
+          }
         end
 
         protected
@@ -34,25 +37,39 @@ module ActiveModelSerializers
 
         private
 
-        def pages_from
+        def location_url
-          return {} if collection.total_pages <= FIRST_PAGE
+          url_for_page(collection.current_page)
-
-          {}.tap do |pages|
-            pages[:self] = collection.current_page
-
-            unless collection.current_page == FIRST_PAGE
-              pages[:first] = FIRST_PAGE
-              pages[:prev]  = collection.current_page - FIRST_PAGE
         end
 
-            unless collection.current_page == collection.total_pages
+        def first_page_url
-              pages[:next] = collection.current_page + FIRST_PAGE
+          url_for_page(1)
-              pages[:last] = collection.total_pages
         end
+
+        def last_page_url
+          if collection.total_pages == 0
+            url_for_page(FIRST_PAGE)
+          else
+            url_for_page(collection.total_pages)
           end
         end
 
-        def url(options)
+        def prev_page_url
+          return nil if collection.current_page == FIRST_PAGE
+          url_for_page(collection.current_page - FIRST_PAGE)
+        end
+
+        def next_page_url
+          return nil if collection.total_pages == 0 || collection.current_page == collection.total_pages
+          url_for_page(collection.next_page)
+        end
+
+        def url_for_page(number)
+          params = query_parameters.dup
+          params[:page] = { size: per_page, number: number }
+          "#{url(adapter_options)}?#{params.to_query}"
+        end
+
+        def url(options = {})
           @url ||= options.fetch(:links, {}).fetch(:self, nil) || request_url
         end
 
@@ -63,6 +80,10 @@ module ActiveModelSerializers
         def query_parameters
           @query_parameters ||= context.query_parameters
         end
+
+        def per_page
+          @per_page ||= collection.try(:per_page) || collection.try(:limit_value) || collection.size
+        end
       end
     end
   end

lib/active_model_serializers/adapter/json_api/relationship.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Adapter
     class JsonApi
@@ -43,10 +45,16 @@ module ActiveModelSerializers
         end
 
         def data_for_one(association)
-          if association.belongs_to? &&
+          if belongs_to_id_on_self?(association)
-              parent_serializer.object.respond_to?(association.reflection.foreign_key)
+            id = parent_serializer.read_attribute_for_serialization(association.reflection.foreign_key)
-            id = parent_serializer.object.send(association.reflection.foreign_key)
+            type =
-            type = association.reflection.type.to_s
+              if association.polymorphic?
+                # We can't infer resource type for polymorphic relationships from the serializer.
+                # We can ONLY know a polymorphic resource type by inspecting each resource.
+                association.lazy_association.serializer.json_key
+              else
+                association.reflection.type.to_s
+              end
             ResourceIdentifier.for_type_with_id(type, id, serializable_resource_options)
           else
             # TODO(BF): Process relationship without evaluating lazy_association
@@ -86,6 +94,12 @@ module ActiveModelSerializers
           meta = association.meta
           meta.respond_to?(:call) ? parent_serializer.instance_eval(&meta) : meta
         end
+
+        def belongs_to_id_on_self?(association)
+          parent_serializer.config.jsonapi_use_foreign_key_on_belongs_to_relationship &&
+            association.belongs_to? &&
+            parent_serializer.object.respond_to?(association.reflection.foreign_key)
+        end
       end
     end
   end

lib/active_model_serializers/adapter/json_api/resource_identifier.rb

@@ -1,33 +1,37 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Adapter
     class JsonApi
       class ResourceIdentifier
-        def self.type_for(class_name, serializer_type = nil, transform_options = {})
+        def self.type_for(serializer, serializer_type = nil, transform_options = {})
-          if serializer_type
+          raw_type = serializer_type ? serializer_type : raw_type_from_serializer_object(serializer.object)
-            raw_type = serializer_type
-          else
-            inflection =
-              if ActiveModelSerializers.config.jsonapi_resource_type == :singular
-                :singularize
-              else
-                :pluralize
-              end
-
-            raw_type = class_name.underscore
-            raw_type = ActiveSupport::Inflector.public_send(inflection, raw_type)
-            raw_type
-              .gsub!('/'.freeze, ActiveModelSerializers.config.jsonapi_namespace_separator)
-            raw_type
-          end
           JsonApi.send(:transform_key_casing!, raw_type, transform_options)
         end
 
         def self.for_type_with_id(type, id, options)
-          return nil if id.blank?
+          type = inflect_type(type)
-          {
+          type = type_for(:no_class_needed, type, options)
-            id: id.to_s,
+          if id.blank?
-            type: type_for(:no_class_needed, type, options)
+            nil
-          }
+          else
+            { id: id.to_s, type: type }
+          end
+        end
+
+        def self.raw_type_from_serializer_object(object)
+          class_name = object.class.name # should use model_name
+          raw_type = class_name.underscore
+          raw_type = inflect_type(raw_type)
+          raw_type
+            .gsub!('/'.freeze, ActiveModelSerializers.config.jsonapi_namespace_separator)
+          raw_type
+        end
+
+        def self.inflect_type(type)
+          singularize = ActiveModelSerializers.config.jsonapi_resource_type == :singular
+          inflection = singularize ? :singularize : :pluralize
+          ActiveSupport::Inflector.public_send(inflection, type)
         end
 
         # {http://jsonapi.org/format/#document-resource-identifier-objects Resource Identifier Objects}
@@ -37,8 +41,11 @@ module ActiveModelSerializers
         end
 
         def as_json
-          return nil if id.blank?
+          if id.blank?
-          { id: id, type: type }
+            { type: type }
+          else
+            { id: id.to_s, type: type }
+          end
         end
 
         protected
@@ -48,7 +55,8 @@ module ActiveModelSerializers
         private
 
         def type_for(serializer, transform_options)
-          self.class.type_for(serializer.object.class.name, serializer._type, transform_options)
+          serializer_type = serializer._type
+          self.class.type_for(serializer, serializer_type, transform_options)
         end
 
         def id_for(serializer)

lib/active_model_serializers/adapter/null.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Adapter
     class Null < Base

lib/active_model_serializers/callbacks.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Adapted from
 # https://github.com/rails/rails/blob/7f18ea14c8/activejob/lib/active_job/callbacks.rb
 require 'active_support/callbacks'

lib/active_model_serializers/deprecate.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 ##
 # Provides a single method +deprecate+ to be used to declare when
 # something is going away.

lib/active_model_serializers/deserialization.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Deserialization
     module_function

lib/active_model_serializers/json_pointer.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module JsonPointer
     module_function

lib/active_model_serializers/logging.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 ##
 # ActiveModelSerializers::Logging
 #

lib/active_model_serializers/lookup_chain.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module LookupChain
     # Standard appending of Serializer to the resource name.

lib/active_model_serializers/model.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # ActiveModelSerializers::Model is a convenient superclass for making your models
 # from Plain-Old Ruby Objects (PORO). It also serves as a reference implementation
 # that satisfies ActiveModel::Serializer::Lint::Tests.

lib/active_model_serializers/railtie.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rails/railtie'
 require 'action_controller'
 require 'action_controller/railtie'
@@ -5,6 +7,8 @@ require 'action_controller/serialization'
 
 module ActiveModelSerializers
   class Railtie < Rails::Railtie
+    config.eager_load_namespaces << ActiveModelSerializers
+
     config.to_prepare do
       ActiveModel::Serializer.serializers_cache.clear
     end

lib/active_model_serializers/register_jsonapi_renderer.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Based on discussion in https://github.com/rails/rails/pull/23712#issuecomment-184977238,
 # the JSON API media type will have its own format/renderer.
 #

lib/active_model_serializers/serializable_resource.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'set'
 
 module ActiveModelSerializers
@@ -14,8 +16,8 @@ module ActiveModelSerializers
     # @return the serializable_resource, ready for #as_json/#to_json/#serializable_hash.
     def initialize(resource, options = {})
       @resource = resource
-      @adapter_opts, @serializer_opts =
+      @adapter_opts = options.select { |k, _| ADAPTER_OPTION_KEYS.include? k }
-        options.partition { |k, _| ADAPTER_OPTION_KEYS.include? k }.map { |h| Hash[h] }
+      @serializer_opts = options.reject { |k, _| ADAPTER_OPTION_KEYS.include? k }
     end
 
     def serialization_scope=(scope)

lib/active_model_serializers/serialization_context.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'active_support/core_ext/array/extract_options'
 module ActiveModelSerializers
   class SerializationContext

lib/active_model_serializers/test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Test
     extend ActiveSupport::Autoload

lib/active_model_serializers/test/schema.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module ActiveModelSerializers
   module Test
     module Schema

lib/active_model_serializers/test/serializer.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'set'
 module ActiveModelSerializers
   module Test

lib/generators/rails/resource_override.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'rails/generators'
 require 'rails/generators/rails/resource/resource_generator'
 

lib/generators/rails/serializer_generator.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Rails
   module Generators
     class SerializerGenerator < NamedBase

lib/grape/active_model_serializers.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # To add Grape support, require 'grape/active_model_serializers' in the base of your Grape endpoints
 # Then add 'include Grape::ActiveModelSerializers' to enable the formatter and helpers
 require 'active_model_serializers'

lib/grape/formatters/active_model_serializers.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # A Grape response formatter that can be used as 'formatter :json, Grape::Formatters::ActiveModelSerializers'
 #
 # Serializer options can be passed as a hash from your Grape endpoint using env[:active_model_serializer_options],

lib/grape/helpers/active_model_serializers.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Helpers can be included in your Grape endpoint as: helpers Grape::Helpers::ActiveModelSerializers
 
 module Grape

lib/tasks/rubocop.rake

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 begin
   require 'rubocop'
   require 'rubocop/rake_task'

test/action_controller/adapter_selector_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActionController

test/action_controller/explicit_serializer_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActionController

test/action_controller/json/include_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActionController

test/action_controller/json_api/deserialization_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActionController
@@ -45,7 +47,7 @@ module ActionController
           response = JSON.parse(@response.body)
           expected = {
             'restriction_for_id' => '67',
-            'restriction_for_type' => 'discounts',
+            'restriction_for_type' => 'Discount',
             'restricted_to_id' => nil,
             'restricted_to_type' => nil
           }

test/action_controller/json_api/errors_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActionController

test/action_controller/json_api/fields_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActionController

test/action_controller/json_api/linked_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActionController

test/action_controller/json_api/pagination_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 require 'will_paginate/array'
 require 'kaminari'
@@ -58,8 +60,10 @@ module ActionController
           assert_equal expected_links, response['links']
         end
 
-        def test_render_only_last_and_next_pagination_links
+        def test_render_only_first_last_and_next_pagination_links
           expected_links = { 'self' => "#{WILL_PAGINATE_URI}?page%5Bnumber%5D=1&page%5Bsize%5D=2",
+                             'first' => "#{WILL_PAGINATE_URI}?page%5Bnumber%5D=1&page%5Bsize%5D=2",
+                             'prev' => nil,
                              'next' => "#{WILL_PAGINATE_URI}?page%5Bnumber%5D=2&page%5Bsize%5D=2",
                              'last' => "#{WILL_PAGINATE_URI}?page%5Bnumber%5D=2&page%5Bsize%5D=2" }
           get :render_pagination_using_will_paginate, params: { page: { number: 1, size: 2 } }
@@ -78,17 +82,21 @@ module ActionController
           assert_equal expected_links, response['links']
         end
 
-        def test_render_only_prev_and_first_pagination_links
+        def test_render_only_prev_first_and_last_pagination_links
           expected_links = { 'self' => "#{KAMINARI_URI}?page%5Bnumber%5D=3&page%5Bsize%5D=1",
                              'first' => "#{KAMINARI_URI}?page%5Bnumber%5D=1&page%5Bsize%5D=1",
-                             'prev' => "#{KAMINARI_URI}?page%5Bnumber%5D=2&page%5Bsize%5D=1" }
+                             'prev' => "#{KAMINARI_URI}?page%5Bnumber%5D=2&page%5Bsize%5D=1",
+                             'next' => nil,
+                             'last' => "#{KAMINARI_URI}?page%5Bnumber%5D=3&page%5Bsize%5D=1" }
           get :render_pagination_using_kaminari, params: { page: { number: 3, size: 1 } }
           response = JSON.parse(@response.body)
           assert_equal expected_links, response['links']
         end
 
-        def test_render_only_last_and_next_pagination_links_with_additional_params
+        def test_render_only_first_last_and_next_pagination_links_with_additional_params
           expected_links = { 'self' => "#{WILL_PAGINATE_URI}?page%5Bnumber%5D=1&page%5Bsize%5D=2&teste=additional",
+                             'first' => "#{WILL_PAGINATE_URI}?page%5Bnumber%5D=1&page%5Bsize%5D=2&teste=additional",
+                             'prev' => nil,
                              'next' => "#{WILL_PAGINATE_URI}?page%5Bnumber%5D=2&page%5Bsize%5D=2&teste=additional",
                              'last' => "#{WILL_PAGINATE_URI}?page%5Bnumber%5D=2&page%5Bsize%5D=2&teste=additional" }
           get :render_pagination_using_will_paginate, params: { page: { number: 1, size: 2 }, teste: 'additional' }
@@ -96,10 +104,12 @@ module ActionController
           assert_equal expected_links, response['links']
         end
 
-        def test_render_only_prev_and_first_pagination_links_with_additional_params
+        def test_render_only_prev_first_and_last_pagination_links_with_additional_params
           expected_links = { 'self' => "#{KAMINARI_URI}?page%5Bnumber%5D=3&page%5Bsize%5D=1&teste=additional",
                              'first' => "#{KAMINARI_URI}?page%5Bnumber%5D=1&page%5Bsize%5D=1&teste=additional",
-                             'prev' => "#{KAMINARI_URI}?page%5Bnumber%5D=2&page%5Bsize%5D=1&teste=additional" }
+                             'prev' => "#{KAMINARI_URI}?page%5Bnumber%5D=2&page%5Bsize%5D=1&teste=additional",
+                             'next' => nil,
+                             'last' => "#{KAMINARI_URI}?page%5Bnumber%5D=3&page%5Bsize%5D=1&teste=additional" }
           get :render_pagination_using_kaminari, params: { page: { number: 3, size: 1 }, teste: 'additional' }
           response = JSON.parse(@response.body)
           assert_equal expected_links, response['links']

test/action_controller/json_api/transform_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActionController

test/action_controller/lookup_proc_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActionController

test/action_controller/namespace_lookup_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActionController
@@ -123,7 +125,12 @@ module ActionController
       tests Api::V3::LookupTestController
 
       setup do
-        @test_namespace = self.class.parent
+        @test_namespace =
+          if Module.method_defined?(:module_parent)
+            self.class.module_parent
+          else
+            self.class.parent
+          end
       end
 
       test 'uses request headers to determine the namespace' do

test/action_controller/serialization_scope_name_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module SerializationScopeTesting

test/action_controller/serialization_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActionController
@@ -457,13 +459,19 @@ module ActionController
       end
 
       def test_render_event_is_emitted
-        subscriber = ::ActiveSupport::Notifications.subscribe('render.active_model_serializers') do |name|
+        subscriber = ::ActiveSupport::Notifications.subscribe('render.active_model_serializers') do |subscribed_event|
-          @name = name
+          @subscribed_event = subscribed_event
         end
 
         get :render_using_implicit_serializer
 
-        assert_equal 'render.active_model_serializers', @name
+        subscribed_event_name =
+          if @subscribed_event.is_a?(String)
+            @subscribed_event
+          else
+            @subscribed_event.name # is a ActiveSupport::Notifications::Event
+          end
+        assert_equal 'render.active_model_serializers', subscribed_event_name
       ensure
         ActiveSupport::Notifications.unsubscribe(subscriber) if subscriber
       end

test/active_model_serializers/adapter_for_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActiveModelSerializers

test/active_model_serializers/json_pointer_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActiveModelSerializers

test/active_model_serializers/logging_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActiveModel

test/active_model_serializers/model_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActiveModelSerializers

test/active_model_serializers/railtie_test_isolated.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Execute this test in isolation
 require 'support/isolated_unit'
 

test/active_model_serializers/register_jsonapi_renderer_test_isolated.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'support/isolated_unit'
 require 'minitest/mock'
 require 'action_dispatch'

test/active_model_serializers/serialization_context_test_isolated.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 # Execute this test in isolation
 require 'support/isolated_unit'
 require 'minitest/mock'

test/active_model_serializers/test/schema_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActiveModelSerializers

test/active_model_serializers/test/serializer_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActiveModelSerializers

test/active_record_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 class ActiveRecordTest < ActiveSupport::TestCase

test/adapter/attributes_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 
 module ActiveModelSerializers

test/adapter/deprecation_test.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'test_helper'
 module ActiveModel
   class Serializer