Remove deprecated #set_state from the transaction object

Author: rafaelfranca

activerecord/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Remove deprecated `#set_state` from the transaction object.
+
+    *Rafael Mendonça França*
+
 *   Remove deprecated `#supports_statement_cache?` from the database adapters.
 
     *Rafael Mendonça França*

activerecord/lib/active_record/connection_adapters/abstract/transaction.rb

@@ -40,24 +40,6 @@ def completed?
         committed? || rolledback?
       end
 
-      def set_state(state)
-        ActiveSupport::Deprecation.warn(<<-MSG.squish)
-          The set_state method is deprecated and will be removed in
-          Rails 6.0. Please use rollback! or commit! to set transaction
-          state directly.
-        MSG
-        case state
-        when :rolledback
-          rollback!
-        when :committed
-          commit!
-        when nil
-          nullify!
-        else
-          raise ArgumentError, "Invalid transaction state: #{state}"
-        end
-      end
-
       def rollback!
         @children.each { |c| c.rollback! }
         @state = :rolledback

activerecord/test/cases/transactions_test.rb

@@ -884,17 +884,6 @@ def test_transactions_state_from_commit
     assert_predicate transaction.state, :committed?
   end
 
-  def test_set_state_method_is_deprecated
-    connection = Topic.connection
-    transaction = ActiveRecord::ConnectionAdapters::TransactionManager.new(connection).begin_transaction
-
-    transaction.commit
-
-    assert_deprecated do
-      transaction.state.set_state(:rolledback)
-    end
-  end
-
   def test_mark_transaction_state_as_committed
     connection = Topic.connection
     transaction = ActiveRecord::ConnectionAdapters::TransactionManager.new(connection).begin_transaction