Merge pull request #26 from github/kill-whiny-nils

Kill whiny nils

activerecord/lib/active_record/associations/association_proxy.rb

@@ -47,14 +47,29 @@ module ActiveRecord
     # instantiation of the actual post records.
     class AssociationProxy #:nodoc:
       alias_method :proxy_respond_to?, :respond_to?
-      alias_method :proxy_extend, :extend
       delegate :to_param, :to => :proxy_target
       instance_methods.each { |m| undef_method m unless m.to_s =~ /^(?:nil\?|send|object_id)$|^__|^respond_to_missing|proxy_/ }
 
+      def self.new(owner, reflection)
+        klass =
+          reflection.cached_extend_class ||=
+            if reflection.options[:extend]
+              const_name = "AR_CACHED_EXTEND_CLASS_#{reflection.name}_#{reflection.options[:extend].join("_").gsub("::","_")}"
+              reflection.active_record.const_set(const_name, Class.new(self) do
+                include *reflection.options[:extend]
+              end)
+            else
+              self
+            end
+
+        proxy = klass.allocate
+        proxy.send(:initialize, owner, reflection)
+        proxy
+      end
+
       def initialize(owner, reflection)
         @owner, @reflection = owner, reflection
         reflection.check_validity!
-        Array(reflection.options[:extend]).each { |ext| proxy_extend(ext) }
         reset
       end
 

activerecord/lib/active_record/reflection.rb

@@ -77,6 +77,7 @@ module ActiveRecord
     # those classes. Objects of AggregateReflection and AssociationReflection are returned by the Reflection::ClassMethods.
     class MacroReflection
       attr_reader :active_record
+      attr_accessor :cached_extend_class
 
       def initialize(macro, name, options, active_record)
         @macro, @name, @options, @active_record = macro, name, options, active_record

activesupport/lib/active_support/concern.rb

@@ -0,0 +1,134 @@
+module ActiveSupport
+  # A typical module looks like this:
+  #
+  #   module M
+  #     def self.included(base)
+  #       base.extend ClassMethods
+  #       base.class_eval do
+  #         scope :disabled, -> { where(disabled: true) }
+  #       end
+  #     end
+  #
+  #     module ClassMethods
+  #       ...
+  #     end
+  #   end
+  #
+  # By using <tt>ActiveSupport::Concern</tt> the above module could instead be
+  # written as:
+  #
+  #   require 'active_support/concern'
+  #
+  #   module M
+  #     extend ActiveSupport::Concern
+  #
+  #     included do
+  #       scope :disabled, -> { where(disabled: true) }
+  #     end
+  #
+  #     module ClassMethods
+  #       ...
+  #     end
+  #   end
+  #
+  # Moreover, it gracefully handles module dependencies. Given a +Foo+ module
+  # and a +Bar+ module which depends on the former, we would typically write the
+  # following:
+  #
+  #   module Foo
+  #     def self.included(base)
+  #       base.class_eval do
+  #         def self.method_injected_by_foo
+  #           ...
+  #         end
+  #       end
+  #     end
+  #   end
+  #
+  #   module Bar
+  #     def self.included(base)
+  #       base.method_injected_by_foo
+  #     end
+  #   end
+  #
+  #   class Host
+  #     include Foo # We need to include this dependency for Bar
+  #     include Bar # Bar is the module that Host really needs
+  #   end
+  #
+  # But why should +Host+ care about +Bar+'s dependencies, namely +Foo+? We
+  # could try to hide these from +Host+ directly including +Foo+ in +Bar+:
+  #
+  #   module Bar
+  #     include Foo
+  #     def self.included(base)
+  #       base.method_injected_by_foo
+  #     end
+  #   end
+  #
+  #   class Host
+  #     include Bar
+  #   end
+  #
+  # Unfortunately this won't work, since when +Foo+ is included, its <tt>base</tt>
+  # is the +Bar+ module, not the +Host+ class. With <tt>ActiveSupport::Concern</tt>,
+  # module dependencies are properly resolved:
+  #
+  #   require 'active_support/concern'
+  #
+  #   module Foo
+  #     extend ActiveSupport::Concern
+  #     included do
+  #       def self.method_injected_by_foo
+  #         ...
+  #       end
+  #     end
+  #   end
+  #
+  #   module Bar
+  #     extend ActiveSupport::Concern
+  #     include Foo
+  #
+  #     included do
+  #       self.method_injected_by_foo
+  #     end
+  #   end
+  #
+  #   class Host
+  #     include Bar # works, Bar takes care now of its dependencies
+  #   end
+  module Concern
+    class MultipleIncludedBlocks < StandardError #:nodoc:
+      def initialize
+        super "Cannot define multiple 'included' blocks for a Concern"
+      end
+    end
+
+    def self.extended(base) #:nodoc:
+      base.instance_variable_set(:@_dependencies, [])
+    end
+
+    def append_features(base)
+      if base.instance_variable_defined?(:@_dependencies)
+        base.instance_variable_get(:@_dependencies) << self
+        return false
+      else
+        return false if base < self
+        @_dependencies.each { |dep| base.send(:include, dep) }
+        super
+        base.extend const_get(:ClassMethods) if const_defined?(:ClassMethods)
+        base.class_eval(&@_included_block) if instance_variable_defined?(:@_included_block)
+      end
+    end
+
+    def included(base = nil, &block)
+      if base.nil?
+        raise MultipleIncludedBlocks if instance_variable_defined?(:@_included_block)
+
+        @_included_block = block
+      else
+        super
+      end
+    end
+  end
+end

activesupport/lib/active_support/whiny_nil.rb

@@ -1,64 +0,0 @@
-# Extensions to +nil+ which allow for more helpful error messages for people who
-# are new to Rails.
-#
-# Ruby raises NoMethodError if you invoke a method on an object that does not
-# respond to it:
-#
-#   $ ruby -e nil.destroy
-#   -e:1: undefined method `destroy' for nil:NilClass (NoMethodError)
-#
-# With these extensions, if the method belongs to the public interface of the
-# classes in NilClass::WHINERS the error message suggests which could be the
-# actual intended class:
-#
-#   $ script/runner nil.destroy 
-#   ...
-#   You might have expected an instance of ActiveRecord::Base.
-#   ...
-#
-# NilClass#id exists in Ruby 1.8 (though it is deprecated). Since +id+ is a fundamental
-# method of Active Record models NilClass#id is redefined as well to raise a RuntimeError
-# and warn the user. She probably wanted a model database identifier and the 4
-# returned by the original method could result in obscure bugs.
-#
-# The flag <tt>config.whiny_nils</tt> determines whether this feature is enabled.
-# By default it is on in development and test modes, and it is off in production
-# mode.
-class NilClass
-  WHINERS = [::Array]
-  WHINERS << ::ActiveRecord::Base if defined? ::ActiveRecord
-
-  METHOD_CLASS_MAP = Hash.new
-
-  WHINERS.each do |klass|
-    methods = klass.public_instance_methods - public_instance_methods
-    class_name = klass.name
-    methods.each { |method| METHOD_CLASS_MAP[method.to_sym] = class_name }
-  end
-
-  # Raises a RuntimeError when you attempt to call +id+ on +nil+.
-  def id
-    raise RuntimeError, "Called id for nil, which would mistakenly be 4 -- if you really wanted the id of nil, use object_id", caller
-  end
-
-  private
-    def method_missing(method, *args, &block)
-      # Ruby 1.9.2: disallow explicit coercion via method_missing.
-      if method == :to_ary || method == :to_str
-        super
-      elsif klass = METHOD_CLASS_MAP[method]
-        raise_nil_warning_for klass, method, caller
-      else
-        super
-      end
-    end
-
-    # Raises a NoMethodError when you attempt to call a method on +nil+.
-    def raise_nil_warning_for(class_name = nil, selector = nil, with_caller = nil)
-      message = "You have a nil object when you didn't expect it!"
-      message << "\nYou might have expected an instance of #{class_name}." if class_name
-      message << "\nThe error occurred while evaluating nil.#{selector}" if selector
-
-      raise NoMethodError, message, with_caller || caller
-    end
-end

activesupport/test/concern_test.rb

@@ -0,0 +1,98 @@
+require 'abstract_unit'
+require 'active_support/concern'
+
+class ConcernTest < ActiveSupport::TestCase
+  module Baz
+    extend ActiveSupport::Concern
+
+    module ClassMethods
+      def baz
+        "baz"
+      end
+
+      def included_ran=(value)
+        @@included_ran = value
+      end
+
+      def included_ran
+        @@included_ran
+      end
+    end
+
+    included do
+      self.included_ran = true
+    end
+
+    def baz
+      "baz"
+    end
+  end
+
+  module Bar
+    extend ActiveSupport::Concern
+
+    include Baz
+
+    def bar
+      "bar"
+    end
+
+    def baz
+      "bar+" + super
+    end
+  end
+
+  module Foo
+    extend ActiveSupport::Concern
+
+    include Bar, Baz
+  end
+
+  def setup
+    @klass = Class.new
+  end
+
+  def test_module_is_included_normally
+    @klass.send(:include, Baz)
+    assert_equal "baz", @klass.new.baz
+    assert @klass.included_modules.include?(ConcernTest::Baz)
+  end
+
+  def test_class_methods_are_extended
+    @klass.send(:include, Baz)
+    assert_equal "baz", @klass.baz
+    assert_equal ConcernTest::Baz::ClassMethods, (class << @klass; self.included_modules; end)[0]
+  end
+
+  def test_included_block_is_ran
+    @klass.send(:include, Baz)
+    assert_equal true, @klass.included_ran
+  end
+
+  def test_modules_dependencies_are_met
+    @klass.send(:include, Bar)
+    assert_equal "bar", @klass.new.bar
+    assert_equal "bar+baz", @klass.new.baz
+    assert_equal "baz", @klass.baz
+    assert @klass.included_modules.include?(ConcernTest::Bar)
+  end
+
+  def test_dependencies_with_multiple_modules
+    @klass.send(:include, Foo)
+    assert_equal [ConcernTest::Foo, ConcernTest::Bar, ConcernTest::Baz], @klass.included_modules[0..2]
+  end
+
+  def test_raise_on_multiple_included_calls
+    assert_raises(ActiveSupport::Concern::MultipleIncludedBlocks) do
+      Module.new do
+        extend ActiveSupport::Concern
+
+        included do
+        end
+
+        included do
+        end
+      end
+    end
+  end
+end

activesupport/test/whiny_nil_test.rb

@@ -1,50 +0,0 @@
-# Stub to enable testing without Active Record
-module ActiveRecord
-  class Base
-    def save!
-    end
-  end
-end
-
-require 'abstract_unit'
-require 'active_support/whiny_nil'
-
-class WhinyNilTest < Test::Unit::TestCase
-  def test_unchanged
-    nil.method_thats_not_in_whiners
-  rescue NoMethodError => nme
-    assert(nme.message =~ /nil:NilClass/)
-  end
-
-  def test_active_record
-    nil.save!
-  rescue NoMethodError => nme
-    assert(!(nme.message =~ /nil:NilClass/))
-    assert_match(/nil\.save!/, nme.message)
-  end
-
-  def test_array
-    nil.each
-  rescue NoMethodError => nme
-    assert(!(nme.message =~ /nil:NilClass/))
-    assert_match(/nil\.each/, nme.message)
-  end
-
-  def test_id
-    nil.id
-  rescue RuntimeError => nme
-    assert(!(nme.message =~ /nil:NilClass/))
-  end
-
-  def test_no_to_ary_coercion
-    nil.to_ary
-  rescue NoMethodError => nme
-    assert(nme.message =~ /nil:NilClass/)
-  end
-
-  def test_no_to_str_coercion
-    nil.to_str
-  rescue NoMethodError => nme
-    assert(nme.message =~ /nil:NilClass/)
-  end
-end

railties/environments/development.rb

@@ -5,9 +5,6 @@
 # since you don't have to restart the webserver when you make code changes.
 config.cache_classes = false
 
-# Log error messages when you accidentally call methods on nil.
-config.whiny_nils = true
-
 # Show full error reports and disable caching
 config.action_controller.consider_all_requests_local = true
 config.action_controller.perform_caching             = false

railties/environments/test.rb

@@ -6,9 +6,6 @@
 # and recreated between test runs.  Don't rely on the data there!
 config.cache_classes = true
 
-# Log error messages when you accidentally call methods on nil.
-config.whiny_nils = true
-
 # Show full error reports and disable caching
 config.action_controller.consider_all_requests_local = true
 config.action_controller.perform_caching             = false
@@ -25,4 +22,4 @@ config.action_mailer.delivery_method = :test
 # Use SQL instead of Active Record's schema dumper when creating the test database.
 # This is necessary if your schema can't be completely dumped by the schema dumper,
 # like if you have constraints or database-specific column types
-# config.active_record.schema_format = :sql
+# config.active_record.schema_format = :sql

railties/lib/initializer.rb

@@ -147,7 +147,6 @@ module Rails
       initialize_framework_logging
 
       initialize_dependency_mechanism
-      initialize_whiny_nils
 
       initialize_time_zone
       initialize_i18n
@@ -543,12 +542,6 @@ Run `rake gems:install` to install the missing gems.
       ActiveSupport::Dependencies.mechanism = configuration.cache_classes ? :require : :load
     end
 
-    # Loads support for "whiny nil" (noisy warnings when methods are invoked
-    # on +nil+ values) if Configuration#whiny_nils is true.
-    def initialize_whiny_nils
-      require('active_support/whiny_nil') if configuration.whiny_nils
-    end
-
     # Sets the default value for Time.zone, and turns on ActiveRecord::Base#time_zone_aware_attributes.
     # If assigned value cannot be matched to a TimeZone, an exception will be raised.
     def initialize_time_zone
@@ -752,10 +745,6 @@ Run `rake gems:install` to install the missing gems.
     # The root of the application's views. (Defaults to <tt>app/views</tt>.)
     attr_accessor :view_path
 
-    # Set to +true+ if you want to be warned (noisily) when you try to invoke
-    # any method of +nil+. Set to +false+ for the standard Ruby behavior.
-    attr_accessor :whiny_nils
-
     # The list of plugins to load. If this is set to <tt>nil</tt>, all plugins will
     # be loaded. If this is set to <tt>[]</tt>, no plugins will be loaded. Otherwise,
     # plugins will be loaded in the order specified.
@@ -870,7 +859,6 @@ Run `rake gems:install` to install the missing gems.
       self.preload_frameworks           = default_preload_frameworks
       self.cache_classes                = default_cache_classes
       self.dependency_loading           = default_dependency_loading
-      self.whiny_nils                   = default_whiny_nils
       self.plugins                      = default_plugins
       self.plugin_paths                 = default_plugin_paths
       self.plugin_locators              = default_plugin_locators
@@ -1067,10 +1055,6 @@ Run `rake gems:install` to install the missing gems.
         true
       end
 
-      def default_whiny_nils
-        false
-      end
-
       def default_plugins
         nil
       end