Update MySQL adapter for changes in Rail 7.1

* New initialize with argument forwarding for lazy connection
  init.
* Remove check_version and clear_cache! in favor of base impls.
* Add active?, disconnect!, discard!, text_type?, and
  configure_connection (dummy impl) based on Rails adapter.
* Use any_raw_connection to access version early in adapter boot.

Author: headius

lib/arjdbc/mysql/adapter.rb

@@ -33,11 +33,19 @@ class Mysql2Adapter < AbstractMysqlAdapter
 
       include ArJdbc::MySQL
 
-      def initialize(connection, logger, connection_options, config)
-        superclass_config = config.reverse_merge(prepared_statements: false)
-        super(connection, logger, connection_options, superclass_config)
+      def initialize(...)
+        super
+
+        @config[:flags] ||= 0
+
+        # JDBC mysql appears to use found rows by default: https://dev.mysql.com/doc/connector-j/en/connector-j-connp-props-connection.html
+        # if @config[:flags].kind_of? Array
+        #   @config[:flags].push "FOUND_ROWS"
+        # else
+        #   @config[:flags] |= ::Mysql2::Client::FOUND_ROWS
+        # end
 
-        # configure_connection taken care of at ArJdbc::Abstract::Core
+        @connection_parameters ||= @config
       end
 
       def self.database_exists?(config)
@@ -49,13 +57,6 @@ def self.database_exists?(config)
         conn.disconnect! if conn
       end
 
-      def check_version
-        # for JNDI, don't check version as the whole connection should be lazy
-        return if ::ActiveRecord::ConnectionAdapters::JdbcConnection.jndi_config?(config)
-
-        super
-      end
-
       def supports_json?
         !mariadb? && database_version >= '5.7.8'
       end
@@ -105,13 +106,6 @@ def explain(arel, binds = [])
         MySQL::ExplainPrettyPrinter.new.pp(result, elapsed)
       end
 
-      # Reloading the type map in abstract/statement_cache.rb blows up postgres
-      def clear_cache!
-        # FIXME: This seems to have disappeared in Rails 7?
-        # reload_type_map
-        super
-      end
-
       def each_hash(result) # :nodoc:
         if block_given?
           # FIXME: This is C in mysql2 gem and I just made simplest Ruby
@@ -164,19 +158,50 @@ def _quote(value)
       # CONNECTION MANAGEMENT ====================================
       #++
 
+      def active?
+        !(@raw_connection.nil? || @raw_connection.closed?)  && @lock.synchronize { @raw_connection&.execute_query("/* ping */ SELECT 1") } || false
+      end
+
       alias :reset! :reconnect!
 
+      # Disconnects from the database if already connected.
+      # Otherwise, this method does nothing.
+      def disconnect!
+        @lock.synchronize do
+          super
+          @raw_connection&.close
+          @raw_connection = nil
+        end
+      end
+
+      def discard! # :nodoc:
+        @lock.synchronize do
+          super
+          @raw_connection&.automatic_close = false
+          @raw_connection = nil
+        end
+      end
+
       #
 
       private
+      def text_type?(type)
+        TYPE_MAP.lookup(type).is_a?(Type::String) || TYPE_MAP.lookup(type).is_a?(Type::Text)
+      end
+
+      def configure_connection
+        # @raw_connection.query_options[:as] = :array
+        # @raw_connection.query_options[:database_timezone] = default_timezone
+        super
+      end
 
       # e.g. "5.7.20-0ubuntu0.16.04.1"
       def full_version
         schema_cache.database_version.full_version_string
       end
 
       def get_full_version
-        @full_version ||= @connection.full_version
+        @full_version ||= any_raw_connection.full_version
       end
 
       def jdbc_connection_class(spec)