From 2a8b9f4105af5fc9fc2f4d098405ebe3065222e8 Mon Sep 17 00:00:00 2001
From: Fabian Mersch <f-mer@users.noreply.github.com>
Date: Tue, 22 May 2018 15:06:06 +0200
Subject: [PATCH 1/2] Eager load modules on boot

Using ActiveModelSerializers with a threaded web server eg. Puma
uninitialized constant errors are thrown. Leaving this article for
reference:
http://blog.plataformatec.com.br/2012/08/eager-loading-for-greater-good/.
---
 lib/active_model/serializer.rb                | 22 ++++++++-------
 lib/active_model_serializers.rb               | 28 ++++++++++++-------
 .../adapter/json_api.rb                       | 18 ++++++------
 lib/active_model_serializers/railtie.rb       |  2 ++
 4 files changed, 42 insertions(+), 28 deletions(-)

diff --git a/lib/active_model/serializer.rb b/lib/active_model/serializer.rb
index b5b95736..b6b7be88 100644
--- a/lib/active_model/serializer.rb
+++ b/lib/active_model/serializer.rb
@@ -18,16 +18,18 @@ 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
-    autoload :Adapter
-    autoload :Null
-    autoload :Attribute
-    autoload :Association
-    autoload :Reflection
-    autoload :SingularReflection
-    autoload :CollectionReflection
-    autoload :BelongsToReflection
-    autoload :HasOneReflection
-    autoload :HasManyReflection
+    eager_autoload do
+      autoload :Adapter
+      autoload :Null
+      autoload :Attribute
+      autoload :Association
+      autoload :Reflection
+      autoload :SingularReflection
+      autoload :CollectionReflection
+      autoload :BelongsToReflection
+      autoload :HasOneReflection
+      autoload :HasManyReflection
+    end
     include ActiveSupport::Configurable
     include Caching
 
diff --git a/lib/active_model_serializers.rb b/lib/active_model_serializers.rb
index 6e5c5962..4f4623ff 100644
--- a/lib/active_model_serializers.rb
+++ b/lib/active_model_serializers.rb
@@ -5,16 +5,19 @@ require 'active_support/core_ext/string/inflections'
 require 'active_support/json'
 module ActiveModelSerializers
   extend ActiveSupport::Autoload
-  autoload :Model
-  autoload :Callbacks
-  autoload :Deserialization
-  autoload :SerializableResource
-  autoload :Logging
-  autoload :Test
-  autoload :Adapter
-  autoload :JsonPointer
-  autoload :Deprecate
-  autoload :LookupChain
+  eager_autoload do
+    autoload :Model
+    autoload :Callbacks
+    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))
@@ -46,6 +49,11 @@ 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'
diff --git a/lib/active_model_serializers/adapter/json_api.rb b/lib/active_model_serializers/adapter/json_api.rb
index b225416b..592a9e9e 100644
--- a/lib/active_model_serializers/adapter/json_api.rb
+++ b/lib/active_model_serializers/adapter/json_api.rb
@@ -22,14 +22,16 @@ module ActiveModelSerializers
   module Adapter
     class JsonApi < Base
       extend ActiveSupport::Autoload
-      autoload :Jsonapi
-      autoload :ResourceIdentifier
-      autoload :Relationship
-      autoload :Link
-      autoload :PaginationLinks
-      autoload :Meta
-      autoload :Error
-      autoload :Deserialization
+      eager_autoload do
+        autoload :Jsonapi
+        autoload :ResourceIdentifier
+        autoload :Link
+        autoload :PaginationLinks
+        autoload :Meta
+        autoload :Error
+        autoload :Deserialization
+        autoload :Relationship
+      end
 
       def self.default_key_transform
         :dash
diff --git a/lib/active_model_serializers/railtie.rb b/lib/active_model_serializers/railtie.rb
index d6843c9c..260bf8c2 100644
--- a/lib/active_model_serializers/railtie.rb
+++ b/lib/active_model_serializers/railtie.rb
@@ -5,6 +5,8 @@ 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

From 65313b901bd8c79862538a4edf9fcea2479fc0cd Mon Sep 17 00:00:00 2001
From: Fabian Mersch <f-mer@users.noreply.github.com>
Date: Tue, 22 May 2018 16:48:27 +0200
Subject: [PATCH 2/2] Remove obsolete autoloads

---
 lib/active_model/serializer.rb | 2 --
 1 file changed, 2 deletions(-)

diff --git a/lib/active_model/serializer.rb b/lib/active_model/serializer.rb
index b6b7be88..f6567a70 100644
--- a/lib/active_model/serializer.rb
+++ b/lib/active_model/serializer.rb
@@ -24,8 +24,6 @@ module ActiveModel
       autoload :Attribute
       autoload :Association
       autoload :Reflection
-      autoload :SingularReflection
-      autoload :CollectionReflection
       autoload :BelongsToReflection
       autoload :HasOneReflection
       autoload :HasManyReflection