Fix migration compatibility for default precision value on datetime columns (Round 2)

activerecord/lib/active_record/migration/compatibility.rb

@@ -99,6 +99,11 @@ def references(*args, **options)
             end
           end
           alias :belongs_to :references
+
+          def column(name, type, index: nil, **options)
+            options[:precision] ||= nil
+            super
+          end
         end
 
         def create_table(table_name, **options)
@@ -146,6 +151,11 @@ def timestamps(**options)
             options[:precision] ||= nil
             super
           end
+
+          def column(name, type, index: nil, **options)
+            options[:precision] ||= nil
+            super
+          end
         end
 
         module CommandRecorder

activerecord/test/cases/migration/compatibility_test.rb

@@ -351,7 +351,127 @@ def migrate(x)
         connection.drop_table :more_testings rescue nil
       end
 
-      def test_datetime_doesnt_set_precision_on_change_table
+      def test_datetime_doesnt_set_precision_on_change_table_4_2
+        create_migration = Class.new(ActiveRecord::Migration[4.2]) {
+          def migrate(x)
+            create_table :more_testings do |t|
+              t.datetime :published_at
+            end
+          end
+        }.new
+
+        change_migration = Class.new(ActiveRecord::Migration[4.2]) {
+          def migrate(x)
+            change_table :more_testings do |t|
+              t.datetime :published_at, default: Time.now
+            end
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [create_migration, change_migration], @schema_migration).migrate
+
+        assert connection.column_exists?(:more_testings, :published_at, **precision_implicit_default)
+      ensure
+        connection.drop_table :more_testings rescue nil
+      end
+
+      def test_datetime_doesnt_set_precision_on_change_table_5_0
+        create_migration = Class.new(ActiveRecord::Migration[5.0]) {
+          def migrate(x)
+            create_table :more_testings do |t|
+              t.datetime :published_at
+            end
+          end
+        }.new
+
+        change_migration = Class.new(ActiveRecord::Migration[5.0]) {
+          def migrate(x)
+            change_table :more_testings do |t|
+              t.datetime :published_at, default: Time.now
+            end
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [create_migration, change_migration], @schema_migration).migrate
+
+        assert connection.column_exists?(:more_testings, :published_at, **precision_implicit_default)
+      ensure
+        connection.drop_table :more_testings rescue nil
+      end
+
+      def test_datetime_doesnt_set_precision_on_change_table_5_1
+        create_migration = Class.new(ActiveRecord::Migration[5.1]) {
+          def migrate(x)
+            create_table :more_testings do |t|
+              t.datetime :published_at
+            end
+          end
+        }.new
+
+        change_migration = Class.new(ActiveRecord::Migration[5.1]) {
+          def migrate(x)
+            change_table :more_testings do |t|
+              t.datetime :published_at, default: Time.now
+            end
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [create_migration, change_migration], @schema_migration).migrate
+
+        assert connection.column_exists?(:more_testings, :published_at, **precision_implicit_default)
+      ensure
+        connection.drop_table :more_testings rescue nil
+      end
+
+      def test_datetime_doesnt_set_precision_on_change_table_5_2
+        create_migration = Class.new(ActiveRecord::Migration[5.2]) {
+          def migrate(x)
+            create_table :more_testings do |t|
+              t.datetime :published_at
+            end
+          end
+        }.new
+
+        change_migration = Class.new(ActiveRecord::Migration[5.2]) {
+          def migrate(x)
+            change_table :more_testings do |t|
+              t.datetime :published_at, default: Time.now
+            end
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [create_migration, change_migration], @schema_migration).migrate
+
+        assert connection.column_exists?(:more_testings, :published_at, **precision_implicit_default)
+      ensure
+        connection.drop_table :more_testings rescue nil
+      end
+
+      def test_datetime_doesnt_set_precision_on_change_table_6_0
+        create_migration = Class.new(ActiveRecord::Migration[6.0]) {
+          def migrate(x)
+            create_table :more_testings do |t|
+              t.datetime :published_at
+            end
+          end
+        }.new
+
+        change_migration = Class.new(ActiveRecord::Migration[6.0]) {
+          def migrate(x)
+            change_table :more_testings do |t|
+              t.datetime :published_at, default: Time.now
+            end
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [create_migration, change_migration], @schema_migration).migrate
+
+        assert connection.column_exists?(:more_testings, :published_at, **precision_implicit_default)
+      ensure
+        connection.drop_table :more_testings rescue nil
+      end
+
+      def test_datetime_doesnt_set_precision_on_change_table_6_1
         create_migration = Class.new(ActiveRecord::Migration[6.1]) {
           def migrate(x)
             create_table :more_testings do |t|