Fix `t.timestamps` missing `null: false` in `change_table bulk: true`

4 files changed, 36 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index 5479ddab71..ce2a1737f9 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -709,6 +709,8 @@ module ActiveRecord
         end
 
         def add_timestamps_for_alter(table_name, options = {})
+          options[:null] = false if options[:null].nil?
+
           [add_column_for_alter(table_name, :created_at, :datetime, options), add_column_for_alter(table_name, :updated_at, :datetime, options)]
         end
 
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index 7cf371be68..9c44cf46aa 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -716,6 +716,8 @@ module ActiveRecord
           end
 
           def add_timestamps_for_alter(table_name, options = {})
+            options[:null] = false if options[:null].nil?
+
             [add_column_for_alter(table_name, :created_at, :datetime, options), add_column_for_alter(table_name, :updated_at, :datetime, options)]
           end
 
diff --git a/activerecord/test/cases/ar_schema_test.rb b/activerecord/test/cases/ar_schema_test.rb
index 8e796a6f13..98af75e8ca 100644
--- a/activerecord/test/cases/ar_schema_test.rb
+++ b/activerecord/test/cases/ar_schema_test.rb
@@ -133,6 +133,21 @@ class ActiveRecordSchemaTest < ActiveRecord::TestCase
     assert @connection.column_exists?(:has_timestamps, :updated_at, null: false)
   end
 
+  if ActiveRecord::Base.connection.supports_bulk_alter?
+    def test_timestamps_without_null_set_null_to_false_on_change_table_with_bulk
+      ActiveRecord::Schema.define do
+        create_table :has_timestamps
+
+        change_table :has_timestamps, bulk: true do |t|
+          t.timestamps default: Time.now
+        end
+      end
+
+      assert @connection.column_exists?(:has_timestamps, :created_at, null: false)
+      assert @connection.column_exists?(:has_timestamps, :updated_at, null: false)
+    end
+  end
+
   def test_timestamps_without_null_set_null_to_false_on_add_timestamps
     ActiveRecord::Schema.define do
       create_table :has_timestamps
diff --git a/activerecord/test/cases/migration/compatibility_test.rb b/activerecord/test/cases/migration/compatibility_test.rb
index 667c118d9a..418793d1af 100644
--- a/activerecord/test/cases/migration/compatibility_test.rb
+++ b/activerecord/test/cases/migration/compatibility_test.rb
@@ -107,6 +107,23 @@ module ActiveRecord
         assert connection.column_exists?(:testings, :updated_at, null: true)
       end
 
+      if ActiveRecord::Base.connection.supports_bulk_alter?
+        def test_timestamps_have_null_constraints_if_not_present_in_migration_of_change_table_with_bulk
+          migration = Class.new(ActiveRecord::Migration[4.2]) {
+            def migrate(x)
+              change_table :testings, bulk: true do |t|
+                t.timestamps
+              end
+            end
+          }.new
+
+          ActiveRecord::Migrator.new(:up, [migration]).migrate
+
+          assert connection.column_exists?(:testings, :created_at, null: true)
+          assert connection.column_exists?(:testings, :updated_at, null: true)
+        end
+      end
+
       def test_timestamps_have_null_constraints_if_not_present_in_migration_for_adding_timestamps_to_existing_table
         migration = Class.new(ActiveRecord::Migration[4.2]) {
           def migrate(x)