Revert "Get rid of the ActiveRecord::Model::DeprecationProxy thing."

This reverts commit 83846838252397b3781eed165ca301e05db39293.

15 files changed, 88 insertions, 28 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index b4831c1fac..ffd19a5334 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -945,14 +945,7 @@
       * Plugins & libraries etc that add methods to `ActiveRecord::Base`
         will not be compatible with `ActiveRecord::Model`. Those libraries
         should add to `ActiveRecord::Model` instead (which is included in
-        `Base`). This should be done using the `:active_record_model`
-        load hook, which executes before `ActiveRecord::Base` loads:
-
-            ActiveSupport.on_load(:active_record_model) do
-              include MyPlugin
-            end
-
-        Or better still, avoid monkey-patching AR and instead
+        `Base`), or better still, avoid monkey-patching AR and instead
         provide a module that users can include where they need it.
 
       * To minimise the risk of conflicts with other code, it is
diff --git a/activerecord/lib/active_record/attribute_methods/dirty.rb b/activerecord/lib/active_record/attribute_methods/dirty.rb
index b4d227eeee..59f209cec8 100644
--- a/activerecord/lib/active_record/attribute_methods/dirty.rb
+++ b/activerecord/lib/active_record/attribute_methods/dirty.rb
@@ -2,7 +2,7 @@ require 'active_support/core_ext/module/attribute_accessors'
 require 'active_support/deprecation'
 
 module ActiveRecord
-  ActiveSupport.on_load(:active_record_model) do
+  ActiveSupport.on_load(:active_record_config) do
     mattr_accessor :partial_writes, instance_accessor: false
     self.partial_writes = true
   end
diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb
index 1b1e732eb1..46fd6ebfb3 100644
--- a/activerecord/lib/active_record/attribute_methods/read.rb
+++ b/activerecord/lib/active_record/attribute_methods/read.rb
@@ -1,5 +1,5 @@
 module ActiveRecord
-  ActiveSupport.on_load(:active_record_model) do
+  ActiveSupport.on_load(:active_record_config) do
     mattr_accessor :attribute_types_cached_by_default, instance_accessor: false
   end
 
diff --git a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
index 95bbf68433..f36a5806a9 100644
--- a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
+++ b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
@@ -1,6 +1,6 @@
 
 module ActiveRecord
-  ActiveSupport.on_load(:active_record_model) do
+  ActiveSupport.on_load(:active_record_config) do
     mattr_accessor :time_zone_aware_attributes, instance_accessor: false
     self.time_zone_aware_attributes = false
 
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index 258c222f7b..a4705b24ca 100644
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -323,6 +323,6 @@ module ActiveRecord #:nodoc:
   class Base
     include ActiveRecord::Model
   end
-
-  ActiveSupport.run_load_hooks(:active_record, Base)
 end
+
+ActiveSupport.run_load_hooks(:active_record, ActiveRecord::Model::DeprecationProxy.new)
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index f1e65f538b..f97c363871 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -3,7 +3,7 @@ require 'active_support/core_ext/object/duplicable'
 require 'thread'
 
 module ActiveRecord
-  ActiveSupport.on_load(:active_record_model) do
+  ActiveSupport.on_load(:active_record_config) do
     ##
     # :singleton-method:
     #
diff --git a/activerecord/lib/active_record/explain.rb b/activerecord/lib/active_record/explain.rb
index 72e09945b5..9e0390bed1 100644
--- a/activerecord/lib/active_record/explain.rb
+++ b/activerecord/lib/active_record/explain.rb
@@ -1,7 +1,7 @@
 require 'active_support/lazy_load_hooks'
 
 module ActiveRecord
-  ActiveSupport.on_load(:active_record_model) do
+  ActiveSupport.on_load(:active_record_config) do
     mattr_accessor :auto_explain_threshold_in_seconds, instance_accessor: false
   end
 
diff --git a/activerecord/lib/active_record/inheritance.rb b/activerecord/lib/active_record/inheritance.rb
index 68e5b1dafa..35273b0d81 100644
--- a/activerecord/lib/active_record/inheritance.rb
+++ b/activerecord/lib/active_record/inheritance.rb
@@ -1,6 +1,6 @@
 
 module ActiveRecord
-  ActiveSupport.on_load(:active_record_model) do
+  ActiveSupport.on_load(:active_record_config) do
     # Determine whether to store the full constant name including namespace when using STI
     mattr_accessor :store_full_sti_class, instance_accessor: false
     self.store_full_sti_class = true
diff --git a/activerecord/lib/active_record/locking/optimistic.rb b/activerecord/lib/active_record/locking/optimistic.rb
index 81195cb355..e96ed00f9c 100644
--- a/activerecord/lib/active_record/locking/optimistic.rb
+++ b/activerecord/lib/active_record/locking/optimistic.rb
@@ -1,5 +1,5 @@
 module ActiveRecord
-  ActiveSupport.on_load(:active_record_model) do
+  ActiveSupport.on_load(:active_record_config) do
     mattr_accessor :lock_optimistically, instance_accessor: false
     self.lock_optimistically = true
   end
diff --git a/activerecord/lib/active_record/model.rb b/activerecord/lib/active_record/model.rb
index 5fcb0359c5..f059840f4d 100644
--- a/activerecord/lib/active_record/model.rb
+++ b/activerecord/lib/active_record/model.rb
@@ -115,21 +115,52 @@ module ActiveRecord
         'type'
       end
     end
+
+    class DeprecationProxy < BasicObject #:nodoc:
+      def initialize(model = Model, base = Base)
+        @model = model
+        @base  = base
+      end
+
+      def method_missing(name, *args, &block)
+        if @model.respond_to?(name, true)
+          @model.send(name, *args, &block)
+        else
+          ::ActiveSupport::Deprecation.warn(
+            "The object passed to the active_record load hook was previously ActiveRecord::Base " \
+            "(a Class). Now it is ActiveRecord::Model (a Module). You have called `#{name}' which " \
+            "is only defined on ActiveRecord::Base. Please change your code so that it works with " \
+            "a module rather than a class. (Model is included in Base, so anything added to Model " \
+            "will be available on Base as well.)"
+          )
+          @base.send(name, *args, &block)
+        end
+      end
+
+      alias send method_missing
+
+      def extend(*mods)
+        ::ActiveSupport::Deprecation.warn(
+          "The object passed to the active_record load hook was previously ActiveRecord::Base " \
+          "(a Class). Now it is ActiveRecord::Model (a Module). You have called `extend' which " \
+          "would add singleton methods to Model. This is presumably not what you want, since the " \
+          "methods would not be inherited down to Base. Rather than using extend, please use " \
+          "ActiveSupport::Concern + include, which will ensure that your class methods are " \
+          "inherited."
+        )
+        @base.extend(*mods)
+      end
+    end
   end
 
-  # This hook is where config accessors on Model should be defined.
+  # This hook is where config accessors on Model get defined.
   #
   # We don't want to just open the Model module and add stuff to it in other files, because
   # that would cause Model to load, which causes all sorts of loading order issues.
   #
   # We need this hook rather than just using the :active_record one, because users of the
   # :active_record hook may need to use config options.
-  #
-  # Users who wish to include a module in Model that they want to also
-  # get inherited by Base should do so using this load hook. After Base
-  # has included Model, any modules subsequently included in Model won't
-  # be inherited by Base.
-  ActiveSupport.run_load_hooks(:active_record_model, Model)
+  ActiveSupport.run_load_hooks(:active_record_config, Model)
 
   # Load Base at this point, because the active_record load hook is run in that file.
   Base
diff --git a/activerecord/lib/active_record/model_schema.rb b/activerecord/lib/active_record/model_schema.rb
index 93bd21d7e9..99de16cd33 100644
--- a/activerecord/lib/active_record/model_schema.rb
+++ b/activerecord/lib/active_record/model_schema.rb
@@ -1,6 +1,6 @@
 
 module ActiveRecord
-  ActiveSupport.on_load(:active_record_model) do
+  ActiveSupport.on_load(:active_record_config) do
     mattr_accessor :primary_key_prefix_type, instance_accessor: false
 
     mattr_accessor :table_name_prefix, instance_accessor: false
diff --git a/activerecord/lib/active_record/nested_attributes.rb b/activerecord/lib/active_record/nested_attributes.rb
index 4d1ff98eb3..2e7fb3bbb3 100644
--- a/activerecord/lib/active_record/nested_attributes.rb
+++ b/activerecord/lib/active_record/nested_attributes.rb
@@ -3,7 +3,7 @@ require 'active_support/core_ext/object/try'
 require 'active_support/core_ext/hash/indifferent_access'
 
 module ActiveRecord
-  ActiveSupport.on_load(:active_record_model) do
+  ActiveSupport.on_load(:active_record_config) do
     mattr_accessor :nested_attributes_options, instance_accessor: false
     self.nested_attributes_options = {}
   end
diff --git a/activerecord/lib/active_record/serialization.rb b/activerecord/lib/active_record/serialization.rb
index 6bdf0db95a..e8dd312a47 100644
--- a/activerecord/lib/active_record/serialization.rb
+++ b/activerecord/lib/active_record/serialization.rb
@@ -1,5 +1,5 @@
 module ActiveRecord #:nodoc:
-  ActiveSupport.on_load(:active_record_model) do
+  ActiveSupport.on_load(:active_record_config) do
     mattr_accessor :include_root_in_json, instance_accessor: false
     self.include_root_in_json = true
   end
diff --git a/activerecord/lib/active_record/timestamp.rb b/activerecord/lib/active_record/timestamp.rb
index 9fb5be7861..ec4588f601 100644
--- a/activerecord/lib/active_record/timestamp.rb
+++ b/activerecord/lib/active_record/timestamp.rb
@@ -1,6 +1,6 @@
 
 module ActiveRecord
-  ActiveSupport.on_load(:active_record_model) do
+  ActiveSupport.on_load(:active_record_config) do
     mattr_accessor :record_timestamps, instance_accessor: false
     self.record_timestamps = true
   end
diff --git a/activerecord/test/cases/inclusion_test.rb b/activerecord/test/cases/inclusion_test.rb
index 297c7a9923..8f095e4953 100644
--- a/activerecord/test/cases/inclusion_test.rb
+++ b/activerecord/test/cases/inclusion_test.rb
@@ -82,6 +82,42 @@ class InclusionUnitTest < ActiveRecord::TestCase
   def test_included_twice
     @klass.send :include, ActiveRecord::Model
   end
+
+  def test_deprecation_proxy
+    proxy = ActiveRecord::Model::DeprecationProxy.new
+
+    assert_equal ActiveRecord::Model.name, proxy.name
+    assert_equal ActiveRecord::Base.superclass, assert_deprecated { proxy.superclass }
+
+    sup, sup2 = nil, nil
+    ActiveSupport.on_load(:__test_active_record_model_deprecation) do
+      sup = superclass
+      sup2 = send(:superclass)
+    end
+    assert_deprecated do
+      ActiveSupport.run_load_hooks(:__test_active_record_model_deprecation, proxy)
+    end
+    assert_equal ActiveRecord::Base.superclass, sup
+    assert_equal ActiveRecord::Base.superclass, sup2
+  end
+
+  test "including in deprecation proxy" do
+    model, base = ActiveRecord::Model.dup, ActiveRecord::Base.dup
+    proxy = ActiveRecord::Model::DeprecationProxy.new(model, base)
+
+    mod = Module.new
+    proxy.include mod
+    assert model < mod
+  end
+
+  test "extending in deprecation proxy" do
+    model, base = ActiveRecord::Model.dup, ActiveRecord::Base.dup
+    proxy = ActiveRecord::Model::DeprecationProxy.new(model, base)
+
+    mod = Module.new
+    assert_deprecated { proxy.extend mod }
+    assert base.singleton_class < mod
+  end
 end
 
 class InclusionFixturesTest < ActiveRecord::TestCase