11 files changed, 30 insertions, 24 deletions
diff --git a/activemodel/lib/active_model.rb b/activemodel/lib/active_model.rb
index 58fe08cc11..8aa1b6f664 100644
--- a/activemodel/lib/active_model.rb
+++ b/activemodel/lib/active_model.rb
@@ -50,6 +50,7 @@ module ActiveModel
   eager_autoload do
     autoload :Errors
     autoload :StrictValidationFailed, 'active_model/errors'
+    autoload :UnknownAttributeError, 'active_model/errors'
   end
 
   module Serializers
diff --git a/activemodel/lib/active_model/attribute_assignment.rb b/activemodel/lib/active_model/attribute_assignment.rb
index 356421476c..087d11f708 100644
--- a/activemodel/lib/active_model/attribute_assignment.rb
+++ b/activemodel/lib/active_model/attribute_assignment.rb
@@ -48,16 +48,5 @@ module ActiveModel
         raise UnknownAttributeError.new(self, k)
       end
     end
-
-    # Raised when unknown attributes are supplied via mass assignment.
-    class UnknownAttributeError < NoMethodError
-      attr_reader :record, :attribute
-
-      def initialize(record, attribute)
-        @record = record
-        @attribute = attribute
-        super("unknown attribute '#{attribute}' for #{@record.class}.")
-      end
-    end
   end
 end
diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index 8326853879..f324788979 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -524,4 +524,15 @@ module ActiveModel
   #   # => ActiveModel::StrictValidationFailed: Name can't be blank
   class StrictValidationFailed < StandardError
   end
+
+  # Raised when unknown attributes are supplied via mass assignment.
+  class UnknownAttributeError < NoMethodError
+    attr_reader :record, :attribute
+
+    def initialize(record, attribute)
+      @record = record
+      @attribute = attribute
+      super("unknown attribute '#{attribute}' for #{@record.class}.")
+    end
+  end
 end
diff --git a/activemodel/test/cases/attribute_assignment_test.rb b/activemodel/test/cases/attribute_assignment_test.rb
index 402caf21f7..64a85e01eb 100644
--- a/activemodel/test/cases/attribute_assignment_test.rb
+++ b/activemodel/test/cases/attribute_assignment_test.rb
@@ -49,7 +49,7 @@ class AttributeAssignmentTest < ActiveModel::TestCase
 
   test "assign non-existing attribute" do
     model = Model.new
-    error = assert_raises(ActiveModel::AttributeAssignment::UnknownAttributeError) do
+    error = assert_raises(ActiveModel::UnknownAttributeError) do
       model.assign_attributes(hz: 1)
     end
 
@@ -59,7 +59,7 @@ class AttributeAssignmentTest < ActiveModel::TestCase
 
   test "assign private attribute" do
     model = Model.new
-    assert_raises(ActiveModel::AttributeAssignment::UnknownAttributeError) do
+    assert_raises(ActiveModel::UnknownAttributeError) do
       model.assign_attributes(metadata: { a: 1 })
     end
   end
diff --git a/activemodel/test/cases/model_test.rb b/activemodel/test/cases/model_test.rb
index 9a8d873ec9..3017f3541b 100644
--- a/activemodel/test/cases/model_test.rb
+++ b/activemodel/test/cases/model_test.rb
@@ -70,7 +70,7 @@ class ModelTest < ActiveModel::TestCase
   end
 
   def test_mixin_initializer_when_args_dont_exist
-    assert_raises(ActiveModel::AttributeAssignment::UnknownAttributeError) do
+    assert_raises(ActiveModel::UnknownAttributeError) do
       SimpleModel.new(hello: 'world')
     end
   end
diff --git a/activerecord/lib/active_record/attribute_assignment.rb b/activerecord/lib/active_record/attribute_assignment.rb
index 483d4200bd..cc265e2af6 100644
--- a/activerecord/lib/active_record/attribute_assignment.rb
+++ b/activerecord/lib/active_record/attribute_assignment.rb
@@ -29,6 +29,13 @@ module ActiveRecord
       assign_multiparameter_attributes(multi_parameter_attributes) unless multi_parameter_attributes.empty?
     end
 
+    # Re-raise with the ActiveRecord constant in case of an error
+    def _assign_attribute(k, v) # :nodoc:
+      super
+    rescue ActiveModel::UnknownAttributeError
+      raise UnknownAttributeError.new(self, k)
+    end
+
     # Assign any deferred nested attributes after the base attributes have been set.
     def assign_nested_parameter_attributes(pairs)
       pairs.each { |k, v| _assign_attribute(k, v) }
diff --git a/activerecord/lib/active_record/errors.rb b/activerecord/lib/active_record/errors.rb
index d710d96a9a..98aee77557 100644
--- a/activerecord/lib/active_record/errors.rb
+++ b/activerecord/lib/active_record/errors.rb
@@ -178,10 +178,8 @@ module ActiveRecord
   class DangerousAttributeError < ActiveRecordError
   end
 
-  UnknownAttributeError = ActiveSupport::Deprecation::DeprecatedConstantProxy.new( # :nodoc:
-    'ActiveRecord::UnknownAttributeError', 
-    'ActiveModel::AttributeAssignment::UnknownAttributeError'
-  )
+  # Raised when unknown attributes are supplied via mass assignment.
+  UnknownAttributeError = ActiveModel::UnknownAttributeError
 
   # Raised when an error occurred while doing a mass assignment to an attribute through the
   # +attributes=+ method. The exception has an +attribute+ property that is the name of the
diff --git a/activerecord/test/cases/associations/has_one_associations_test.rb b/activerecord/test/cases/associations/has_one_associations_test.rb
index 3b6a4038cd..7dc9266074 100644
--- a/activerecord/test/cases/associations/has_one_associations_test.rb
+++ b/activerecord/test/cases/associations/has_one_associations_test.rb
@@ -276,7 +276,7 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
   def test_create_with_inexistent_foreign_key_failing
     firm = Firm.create(name: 'GlobalMegaCorp')
 
-    assert_raises(ActiveModel::AttributeAssignment::UnknownAttributeError) do
+    assert_raises(ActiveRecord::UnknownAttributeError) do
       firm.create_account_with_inexistent_foreign_key
     end
   end
diff --git a/activerecord/test/cases/attribute_methods_test.rb b/activerecord/test/cases/attribute_methods_test.rb
index 243c90e945..ea2b94cbf4 100644
--- a/activerecord/test/cases/attribute_methods_test.rb
+++ b/activerecord/test/cases/attribute_methods_test.rb
@@ -758,12 +758,12 @@ class AttributeMethodsTest < ActiveRecord::TestCase
   def test_bulk_update_respects_access_control
     privatize("title=(value)")
 
-    assert_raise(ActiveModel::AttributeAssignment::UnknownAttributeError) { @target.new(:title => "Rants about pants") }
-    assert_raise(ActiveModel::AttributeAssignment::UnknownAttributeError) { @target.new.attributes = { :title => "Ants in pants" } }
+    assert_raise(ActiveRecord::UnknownAttributeError) { @target.new(:title => "Rants about pants") }
+    assert_raise(ActiveRecord::UnknownAttributeError) { @target.new.attributes = { :title => "Ants in pants" } }
   end
 
   def test_bulk_update_raise_unknown_attribute_error
-    error = assert_raises(ActiveModel::AttributeAssignment::UnknownAttributeError) {
+    error = assert_raises(ActiveRecord::UnknownAttributeError) {
       Topic.new(hello: "world")
     }
     assert_instance_of Topic, error.record
diff --git a/activerecord/test/cases/attributes_test.rb b/activerecord/test/cases/attributes_test.rb
index e7b76b1cf9..927d7950a5 100644
--- a/activerecord/test/cases/attributes_test.rb
+++ b/activerecord/test/cases/attributes_test.rb
@@ -58,7 +58,7 @@ module ActiveRecord
       data = OverloadedType.new(non_existent_decimal: 1)
 
       assert_equal BigDecimal.new(1), data.non_existent_decimal
-      assert_raise ActiveModel::AttributeAssignment::UnknownAttributeError do
+      assert_raise ActiveRecord::UnknownAttributeError do
         UnoverloadedType.new(non_existent_decimal: 1)
       end
     end
diff --git a/activerecord/test/cases/nested_attributes_test.rb b/activerecord/test/cases/nested_attributes_test.rb
index 198cd6f341..c5f6589c22 100644
--- a/activerecord/test/cases/nested_attributes_test.rb
+++ b/activerecord/test/cases/nested_attributes_test.rb
@@ -672,7 +672,7 @@ module NestedAttributesOnACollectionAssociationTests
   end
 
   def test_should_not_assign_destroy_key_to_a_record
-    assert_nothing_raised ActiveModel::AttributeAssignment::UnknownAttributeError do
+    assert_nothing_raised ActiveRecord::UnknownAttributeError do
       @pirate.send(association_setter, { 'foo' => { '_destroy' => '0' }})
     end
   end