From 06b026f0244dbbb5b86472fec778c4bdf630b0ba Mon Sep 17 00:00:00 2001
From: Roberto Miranda <rjmaltamar@gmail.com>
Date: Mon, 28 Jun 2021 21:03:02 +0100
Subject: [PATCH] Fix migration compatibility for default precision value on
 datetime columns (Round 2)

add test cases on default precision from 4.2 to 6.1

Fix compatibility on rails 6.0

Fix compatibility from 5.2 to 4.2
---
 .../active_record/migration/compatibility.rb  |  10 ++
 .../cases/migration/compatibility_test.rb     | 122 +++++++++++++++++-
 2 files changed, 131 insertions(+), 1 deletion(-)

diff --git a/activerecord/lib/active_record/migration/compatibility.rb b/activerecord/lib/active_record/migration/compatibility.rb
index b3d5b3ed82a72..fc6327f823206 100644
--- a/activerecord/lib/active_record/migration/compatibility.rb
+++ b/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
diff --git a/activerecord/test/cases/migration/compatibility_test.rb b/activerecord/test/cases/migration/compatibility_test.rb
index 983feaf6fd2eb..7ea05774d4638 100644
--- a/activerecord/test/cases/migration/compatibility_test.rb
+++ b/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|