Autoloading, dependency loading and middleware registry cleanup

UPGRADING.md

@@ -31,9 +31,25 @@ We did our best to make this transition as painless as possible for you, so here
 * We've setup an [Awesome Faraday](https://github.com/lostisland/awesome-faraday) repository, where you can find and discover adapters.
   We also highlighted their unique features and level of compliance with Faraday's features.
 
+### Autoloading and dependencies
+
+Faraday has until now provided and relied on a complex dynamic dependencies system.
+This would allow to reference classes and require dependencies only when needed (e.g. when running the first request) based
+on the middleware/adapters used.
+As part of Faraday v2.0, we've removed all external dependencies, which means we don't really need this anymore.
+This change should not affect you directly, but if you're registering middleware then be aware of the new syntax:
+
+```ruby
+# `name` here can be anything you want.
+# `klass` is your custom middleware class.
+# This method can also be called on `Faraday::Adapter`, `Faraday::Request` and `Faraday::Response`
+Faraday::Middleware.register_middleware(name: klass)
+```
+
 ### Others
 
 * Rename `Faraday::Request#method` to `#http_method`.
+* Remove `Faraday::Response::Middleware`. You can now use the new `on_complete` callback provided by `Faraday::Middleware`.
 
 ## Faraday 1.0
 

faraday.gemspec

@@ -2,7 +2,7 @@
 
 require_relative 'lib/faraday/version'
 
-Gem::Specification.new do |spec| # rubocop:disable Metrics/BlockLength
+Gem::Specification.new do |spec|
   spec.name    = 'faraday'
   spec.version = Faraday::VERSION
 
@@ -15,14 +15,7 @@ Gem::Specification.new do |spec| # rubocop:disable Metrics/BlockLength
 
   spec.required_ruby_version = '>= 2.4'
 
-  spec.add_dependency 'faraday-em_http', '~> 1.0'
-  spec.add_dependency 'faraday-em_synchrony', '~> 1.0'
-  spec.add_dependency 'faraday-excon', '~> 1.1'
-  spec.add_dependency 'faraday-httpclient', '~> 1.0.1'
   spec.add_dependency 'faraday-net_http', '~> 1.0'
-  spec.add_dependency 'faraday-net_http_persistent', '~> 1.1'
-  spec.add_dependency 'faraday-patron', '~> 1.0'
-  spec.add_dependency 'faraday-rack', '~> 1.0'
   spec.add_dependency 'multipart-post', '>= 1.2', '< 3'
   spec.add_dependency 'ruby2_keywords', '>= 0.0.4'
 

lib/faraday.rb

@@ -4,16 +4,10 @@
 require 'date'
 require 'set'
 require 'forwardable'
-require 'faraday/middleware_registry'
-require 'faraday/dependency_loader'
-
-unless defined?(::Faraday::Timer)
-  require 'timeout'
-  ::Faraday::Timer = Timeout
-end
-
 require 'faraday/version'
 require 'faraday/methods'
+require 'faraday/error'
+require 'faraday/middleware_registry'
 require 'faraday/utils'
 require 'faraday/options'
 require 'faraday/connection'
@@ -23,7 +17,6 @@
 require 'faraday/adapter'
 require 'faraday/request'
 require 'faraday/response'
-require 'faraday/error'
 require 'faraday/file_part'
 require 'faraday/param_part'
 
@@ -101,19 +94,6 @@ def new(url = nil, options = {}, &block)
       Faraday::Connection.new(url, options, &block)
     end
 
-    # @private
-    # Internal: Requires internal Faraday libraries.
-    #
-    # @param libs [Array] one or more relative String names to Faraday classes.
-    # @return [void]
-    def require_libs(*libs)
-      libs.each do |lib|
-        require "#{lib_path}/#{lib}"
-      end
-    end
-
-    alias require_lib require_libs
-
     # Documented elsewhere, see default_adapter reader
     def default_adapter=(adapter)
       @default_connection = nil
@@ -169,6 +149,4 @@ def method_missing(name, *args, &block)
   self.root_path = File.expand_path __dir__
   self.lib_path = File.expand_path 'faraday', __dir__
   self.default_adapter = :net_http
-
-  require_lib 'autoload' unless ENV['FARADAY_NO_AUTOLOAD']
 end

lib/faraday/adapter.rb

@@ -5,14 +5,9 @@ module Faraday
   # responsible for fulfilling a Faraday request.
   class Adapter
     extend MiddlewareRegistry
-    extend DependencyLoader
 
     CONTENT_LENGTH = 'Content-Length'
 
-    register_middleware File.expand_path('adapter', __dir__),
-                        test: [:Test, 'test'],
-                        typhoeus: [:Typhoeus, 'typhoeus']
-
     # This module marks an Adapter as supporting parallel requests.
     module Parallelism
       attr_writer :supports_parallel

lib/faraday/adapter/test.rb

@@ -273,3 +273,5 @@ def call(env)
     end
   end
 end
+
+Faraday::Adapter.register_middleware(test: Faraday::Adapter::Test)

lib/faraday/logging/formatter.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'pp'
+
 module Faraday
   module Logging
     # Serves as an integration point to customize logging

lib/faraday/middleware.rb

@@ -4,7 +4,6 @@ module Faraday
   # Middleware is the basic base class of any Faraday middleware.
   class Middleware
     extend MiddlewareRegistry
-    extend DependencyLoader
 
     attr_reader :app, :options