1 files changed, 369 insertions, 0 deletions
diff --git a/activerecord/test/cases/migration/compatibility_test.rb b/activerecord/test/cases/migration/compatibility_test.rb
new file mode 100644
index 0000000000..69a50674af
--- /dev/null
+++ b/activerecord/test/cases/migration/compatibility_test.rb
@@ -0,0 +1,369 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "support/schema_dumping_helper"
+
+module ActiveRecord
+  class Migration
+    class CompatibilityTest < ActiveRecord::TestCase
+      attr_reader :connection
+      self.use_transactional_tests = false
+
+      def setup
+        super
+        @connection = ActiveRecord::Base.connection
+        @verbose_was = ActiveRecord::Migration.verbose
+        ActiveRecord::Migration.verbose = false
+
+        connection.create_table :testings do |t|
+          t.column :foo, :string, limit: 5
+          t.column :bar, :string, limit: 100
+        end
+      end
+
+      teardown do
+        connection.drop_table :testings rescue nil
+        ActiveRecord::Migration.verbose = @verbose_was
+        ActiveRecord::SchemaMigration.delete_all rescue nil
+      end
+
+      def test_migration_doesnt_remove_named_index
+        connection.add_index :testings, :foo, name: "custom_index_name"
+
+        migration = Class.new(ActiveRecord::Migration[4.2]) {
+          def version; 101 end
+          def migrate(x)
+            remove_index :testings, :foo
+          end
+        }.new
+
+        assert connection.index_exists?(:testings, :foo, name: "custom_index_name")
+        assert_raise(StandardError) { ActiveRecord::Migrator.new(:up, [migration]).migrate }
+        assert connection.index_exists?(:testings, :foo, name: "custom_index_name")
+      end
+
+      def test_migration_does_remove_unnamed_index
+        connection.add_index :testings, :bar
+
+        migration = Class.new(ActiveRecord::Migration[4.2]) {
+          def version; 101 end
+          def migrate(x)
+            remove_index :testings, :bar
+          end
+        }.new
+
+        assert connection.index_exists?(:testings, :bar)
+        ActiveRecord::Migrator.new(:up, [migration]).migrate
+        assert_not connection.index_exists?(:testings, :bar)
+      end
+
+      def test_references_does_not_add_index_by_default
+        migration = Class.new(ActiveRecord::Migration[4.2]) {
+          def migrate(x)
+            create_table :more_testings do |t|
+              t.references :foo
+              t.belongs_to :bar, index: false
+            end
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [migration]).migrate
+
+        assert_not connection.index_exists?(:more_testings, :foo_id)
+        assert_not connection.index_exists?(:more_testings, :bar_id)
+      ensure
+        connection.drop_table :more_testings rescue nil
+      end
+
+      def test_timestamps_have_null_constraints_if_not_present_in_migration_of_create_table
+        migration = Class.new(ActiveRecord::Migration[4.2]) {
+          def migrate(x)
+            create_table :more_testings do |t|
+              t.timestamps
+            end
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [migration]).migrate
+
+        assert connection.columns(:more_testings).find { |c| c.name == "created_at" }.null
+        assert connection.columns(:more_testings).find { |c| c.name == "updated_at" }.null
+      ensure
+        connection.drop_table :more_testings rescue nil
+      end
+
+      def test_timestamps_have_null_constraints_if_not_present_in_migration_of_change_table
+        migration = Class.new(ActiveRecord::Migration[4.2]) {
+          def migrate(x)
+            change_table :testings do |t|
+              t.timestamps
+            end
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [migration]).migrate
+
+        assert connection.columns(:testings).find { |c| c.name == "created_at" }.null
+        assert connection.columns(:testings).find { |c| c.name == "updated_at" }.null
+      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)
+            add_timestamps :testings
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [migration]).migrate
+
+        assert connection.columns(:testings).find { |c| c.name == "created_at" }.null
+        assert connection.columns(:testings).find { |c| c.name == "updated_at" }.null
+      end
+
+      def test_legacy_migrations_raises_exception_when_inherited
+        e = assert_raises(StandardError) do
+          class_eval("class LegacyMigration < ActiveRecord::Migration; end")
+        end
+        assert_match(/LegacyMigration < ActiveRecord::Migration\[4\.2\]/, e.message)
+      end
+
+      if current_adapter?(:PostgreSQLAdapter)
+        class Testing < ActiveRecord::Base
+        end
+
+        def test_legacy_change_column_with_null_executes_update
+          migration = Class.new(ActiveRecord::Migration[5.1]) {
+            def migrate(x)
+              change_column :testings, :foo, :string, limit: 10, null: false, default: "foobar"
+            end
+          }.new
+
+          Testing.create!
+          ActiveRecord::Migrator.new(:up, [migration]).migrate
+          assert_equal ["foobar"], Testing.all.map(&:foo)
+        ensure
+          ActiveRecord::Base.clear_cache!
+        end
+      end
+    end
+  end
+end
+
+module LegacyPrimaryKeyTestCases
+  include SchemaDumpingHelper
+
+  class LegacyPrimaryKey < ActiveRecord::Base
+  end
+
+  def setup
+    @migration = nil
+    @verbose_was = ActiveRecord::Migration.verbose
+    ActiveRecord::Migration.verbose = false
+  end
+
+  def teardown
+    @migration.migrate(:down) if @migration
+    ActiveRecord::Migration.verbose = @verbose_was
+    ActiveRecord::SchemaMigration.delete_all rescue nil
+    LegacyPrimaryKey.reset_column_information
+  end
+
+  def test_legacy_primary_key_should_be_auto_incremented
+    @migration = Class.new(migration_class) {
+      def change
+        create_table :legacy_primary_keys do |t|
+          t.references :legacy_ref
+        end
+      end
+    }.new
+
+    @migration.migrate(:up)
+
+    assert_legacy_primary_key
+
+    legacy_ref = LegacyPrimaryKey.columns_hash["legacy_ref_id"]
+    assert_not_predicate legacy_ref, :bigint?
+
+    record1 = LegacyPrimaryKey.create!
+    assert_not_nil record1.id
+
+    record1.destroy
+
+    record2 = LegacyPrimaryKey.create!
+    assert_not_nil record2.id
+    assert_operator record2.id, :>, record1.id
+  end
+
+  def test_legacy_integer_primary_key_should_not_be_auto_incremented
+    skip if current_adapter?(:SQLite3Adapter)
+
+    @migration = Class.new(migration_class) {
+      def change
+        create_table :legacy_primary_keys, id: :integer do |t|
+        end
+      end
+    }.new
+
+    @migration.migrate(:up)
+
+    assert_raises(ActiveRecord::NotNullViolation) do
+      LegacyPrimaryKey.create!
+    end
+
+    schema = dump_table_schema "legacy_primary_keys"
+    assert_match %r{create_table "legacy_primary_keys", id: :integer, default: nil}, schema
+  end
+
+  def test_legacy_primary_key_in_create_table_should_be_integer
+    @migration = Class.new(migration_class) {
+      def change
+        create_table :legacy_primary_keys, id: false do |t|
+          t.primary_key :id
+        end
+      end
+    }.new
+
+    @migration.migrate(:up)
+
+    assert_legacy_primary_key
+  end
+
+  def test_legacy_primary_key_in_change_table_should_be_integer
+    @migration = Class.new(migration_class) {
+      def change
+        create_table :legacy_primary_keys, id: false do |t|
+          t.integer :dummy
+        end
+        change_table :legacy_primary_keys do |t|
+          t.primary_key :id
+        end
+      end
+    }.new
+
+    @migration.migrate(:up)
+
+    assert_legacy_primary_key
+  end
+
+  def test_add_column_with_legacy_primary_key_should_be_integer
+    @migration = Class.new(migration_class) {
+      def change
+        create_table :legacy_primary_keys, id: false do |t|
+          t.integer :dummy
+        end
+        add_column :legacy_primary_keys, :id, :primary_key
+      end
+    }.new
+
+    @migration.migrate(:up)
+
+    assert_legacy_primary_key
+  end
+
+  def test_legacy_join_table_foreign_keys_should_be_integer
+    @migration = Class.new(migration_class) {
+      def change
+        create_join_table :apples, :bananas do |t|
+        end
+      end
+    }.new
+
+    @migration.migrate(:up)
+
+    schema = dump_table_schema "apples_bananas"
+    assert_match %r{integer "apple_id", null: false}, schema
+    assert_match %r{integer "banana_id", null: false}, schema
+  end
+
+  def test_legacy_join_table_column_options_should_be_overwritten
+    @migration = Class.new(migration_class) {
+      def change
+        create_join_table :apples, :bananas, column_options: { type: :bigint } do |t|
+        end
+      end
+    }.new
+
+    @migration.migrate(:up)
+
+    schema = dump_table_schema "apples_bananas"
+    assert_match %r{bigint "apple_id", null: false}, schema
+    assert_match %r{bigint "banana_id", null: false}, schema
+  end
+
+  if current_adapter?(:Mysql2Adapter)
+    def test_legacy_bigint_primary_key_should_be_auto_incremented
+      @migration = Class.new(migration_class) {
+        def change
+          create_table :legacy_primary_keys, id: :bigint
+        end
+      }.new
+
+      @migration.migrate(:up)
+
+      legacy_pk = LegacyPrimaryKey.columns_hash["id"]
+      assert_predicate legacy_pk, :bigint?
+      assert_predicate legacy_pk, :auto_increment?
+
+      schema = dump_table_schema "legacy_primary_keys"
+      assert_match %r{create_table "legacy_primary_keys", (?!id: :bigint, default: nil)}, schema
+    end
+  else
+    def test_legacy_bigint_primary_key_should_not_be_auto_incremented
+      @migration = Class.new(migration_class) {
+        def change
+          create_table :legacy_primary_keys, id: :bigint do |t|
+          end
+        end
+      }.new
+
+      @migration.migrate(:up)
+
+      assert_raises(ActiveRecord::NotNullViolation) do
+        LegacyPrimaryKey.create!
+      end
+
+      schema = dump_table_schema "legacy_primary_keys"
+      assert_match %r{create_table "legacy_primary_keys", id: :bigint, default: nil}, schema
+    end
+  end
+
+  private
+    def assert_legacy_primary_key
+      assert_equal "id", LegacyPrimaryKey.primary_key
+
+      legacy_pk = LegacyPrimaryKey.columns_hash["id"]
+
+      assert_equal :integer, legacy_pk.type
+      assert_not_predicate legacy_pk, :bigint?
+      assert_not legacy_pk.null
+
+      if current_adapter?(:Mysql2Adapter, :PostgreSQLAdapter)
+        schema = dump_table_schema "legacy_primary_keys"
+        assert_match %r{create_table "legacy_primary_keys", id: :(?:integer|serial), (?!default: nil)}, schema
+      end
+    end
+end
+
+module LegacyPrimaryKeyTest
+  class V5_0 < ActiveRecord::TestCase
+    include LegacyPrimaryKeyTestCases
+
+    self.use_transactional_tests = false
+
+    private
+      def migration_class
+        ActiveRecord::Migration[5.0]
+      end
+  end
+
+  class V4_2 < ActiveRecord::TestCase
+    include LegacyPrimaryKeyTestCases
+
+    self.use_transactional_tests = false
+
+    private
+      def migration_class
+        ActiveRecord::Migration[4.2]
+      end
+  end
+end