Don't assign the attributes if the list is empty.

2 files changed, 5 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/attribute_assignment.rb b/activerecord/lib/active_record/attribute_assignment.rb
index bf9fe70b31..ca5f7b9c6c 100644
--- a/activerecord/lib/active_record/attribute_assignment.rb
+++ b/activerecord/lib/active_record/attribute_assignment.rb
@@ -64,7 +64,7 @@ module ActiveRecord
     #   user.name       # => "Josh"
     #   user.is_admin?  # => true
     def assign_attributes(new_attributes, options = {})
-      return unless new_attributes
+      return if new_attributes.blank?
 
       attributes = new_attributes.stringify_keys
       multi_parameter_attributes = []
diff --git a/activerecord/test/cases/mass_assignment_security_test.rb b/activerecord/test/cases/mass_assignment_security_test.rb
index 2f98d3c646..fc89ced830 100644
--- a/activerecord/test/cases/mass_assignment_security_test.rb
+++ b/activerecord/test/cases/mass_assignment_security_test.rb
@@ -98,6 +98,10 @@ class MassAssignmentSecurityTest < ActiveRecord::TestCase
     Firm.new.assign_attributes(nil)
   end
 
+  def test_mass_assigning_does_not_choke_on_empty_hash
+    Firm.new.assign_attributes({})
+  end
+
   def test_assign_attributes_uses_default_role_when_no_role_is_provided
     p = LoosePerson.new
     p.assign_attributes(attributes_hash)