When we pass id to update_attributes it will try to set new id for that record

4 files changed, 18 insertions, 2 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 771f1333f0..4a6e79c68e 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,4 +1,11 @@
 ## Rails 4.0.0 (unreleased) ##
+*   After extraction of mass-assignment attributes (which protects [id, type]
+    by default) we can pass id to update_attributes and it will update
+    another record because id will be used in where statement. We never have
+    to change id in where statement because we try to set/replace fields for
+    already loaded record but we have to try to set new id for that record.
+
+    *Dmitry Vorotilin*
 
 *   Models with multiple counter cache associations now update correctly on destroy.
     See #7706.
diff --git a/activerecord/lib/active_record/attribute_methods.rb b/activerecord/lib/active_record/attribute_methods.rb
index aa92343f76..769e005c8f 100644
--- a/activerecord/lib/active_record/attribute_methods.rb
+++ b/activerecord/lib/active_record/attribute_methods.rb
@@ -348,7 +348,7 @@ module ActiveRecord
     # Filters the primary keys and readonly attributes from the attribute names.
     def attributes_for_update(attribute_names)
       attribute_names.select do |name|
-        column_for_attribute(name) && !pk_attribute?(name) && !readonly_attribute?(name)
+        column_for_attribute(name) && !readonly_attribute?(name)
       end
     end
 
diff --git a/activerecord/lib/active_record/persistence.rb b/activerecord/lib/active_record/persistence.rb
index b25d0601cb..f881778591 100644
--- a/activerecord/lib/active_record/persistence.rb
+++ b/activerecord/lib/active_record/persistence.rb
@@ -443,7 +443,7 @@ module ActiveRecord
           real_column = db_columns_with_values[i].first
           bind_attrs[column] = klass.connection.substitute_at(real_column, i)
         end
-        stmt = klass.unscoped.where(klass.arel_table[klass.primary_key].eq(id)).arel.compile_update(bind_attrs)
+        stmt = klass.unscoped.where(klass.arel_table[klass.primary_key].eq(id_was)).arel.compile_update(bind_attrs)
         klass.connection.update stmt, 'SQL', db_columns_with_values
       end
     end
diff --git a/activerecord/test/cases/persistence_test.rb b/activerecord/test/cases/persistence_test.rb
index b936cca875..a29189df05 100644
--- a/activerecord/test/cases/persistence_test.rb
+++ b/activerecord/test/cases/persistence_test.rb
@@ -661,6 +661,15 @@ class PersistencesTest < ActiveRecord::TestCase
     topic.reload
     assert !topic.approved?
     assert_equal "The First Topic", topic.title
+
+    assert_raise(ActiveRecord::RecordNotUnique, ActiveRecord::StatementInvalid) do
+      topic.update_attributes(id: 3, title: "Hm is it possible?")
+    end
+    assert_not_equal "Hm is it possible?", Topic.find(3).title
+
+    topic.update_attributes(id: 1234)
+    assert_nothing_raised { topic.reload }
+    assert_equal topic.title, Topic.find(1234).title
   end
 
   def test_update!