1 files changed, 13 insertions, 5 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
index 45e400b75b..92f15de219 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
@@ -1,17 +1,16 @@
+# frozen_string_literal: true
+
 require "active_record/connection_adapters/abstract_mysql_adapter"
 require "active_record/connection_adapters/mysql/database_statements"
 
-gem "mysql2", ">= 0.3.18", "< 0.5"
+gem "mysql2", ">= 0.4.4", "< 0.6.0"
 require "mysql2"
-raise "mysql2 0.4.3 is not supported. Please upgrade to 0.4.4+" if Mysql2::VERSION == "0.4.3"
 
 module ActiveRecord
   module ConnectionHandling # :nodoc:
     # Establishes a connection to the database that's used by all Active Record objects.
     def mysql2_connection(config)
       config = config.symbolize_keys
-
-      config[:username] = "root" if config[:username].nil?
       config[:flags] ||= 0
 
       if config[:flags].kind_of? Array
@@ -59,6 +58,10 @@ module ActiveRecord
         true
       end
 
+      def supports_lazy_transactions?
+        true
+      end
+
       # HELPER METHODS ===========================================
 
       def each_hash(result) # :nodoc:
@@ -105,6 +108,11 @@ module ActiveRecord
         @connection.close
       end
 
+      def discard! # :nodoc:
+        @connection.automatic_close = false
+        @connection = nil
+      end
+
       private
 
         def connect
@@ -113,7 +121,7 @@ module ActiveRecord
         end
 
         def configure_connection
-          @connection.query_options.merge!(as: :array)
+          @connection.query_options[:as] = :array
           super
         end