Move error_number and sql_state into Mysql2::Error initializer

Author: sodabrew

ext/mysql2/client.c

@@ -124,9 +124,11 @@ static VALUE rb_raise_mysql2_error(mysql_client_wrapper *wrapper) {
   rb_enc_associate(rb_sql_state, rb_usascii_encoding());
 #endif
 
-  e = rb_funcall(cMysql2Error, intern_new, 2, rb_error_msg, LONG2FIX(wrapper->server_version));
-  rb_funcall(e, intern_error_number_eql, 1, UINT2NUM(mysql_errno(wrapper->client)));
-  rb_funcall(e, intern_sql_state_eql, 1, rb_sql_state);
+  e = rb_funcall(cMysql2Error, intern_new, 4,
+                 rb_error_msg,
+                 LONG2FIX(wrapper->server_version),
+                 UINT2NUM(mysql_errno(wrapper->client)),
+                 rb_sql_state);
   rb_exc_raise(e);
   return Qnil;
 }

lib/mysql2/error.rb

@@ -8,24 +8,21 @@ class Error < StandardError
       :replace => '?'.freeze,
     }.freeze
 
-    attr_accessor :error_number
-    attr_reader :sql_state
+    attr_reader :error_number, :sql_state
     attr_writer :server_version
 
     # Mysql gem compatibility
     alias_method :errno, :error_number
     alias_method :error, :message
 
-    def initialize(msg, server_version = nil)
+    def initialize(msg, server_version=nil, error_number=nil, sql_state=nil)
       self.server_version = server_version
+      self.error_number = error_number
+      self.sql_state = sql_state.respond_to?(:encode) ? sql_state.encode(ENCODE_OPTS) : sql_state
 
       super(clean_message(msg))
     end
 
-    def sql_state=(state)
-      @sql_state = state.respond_to?(:encode) ? state.encode(ENCODE_OPTS) : state
-    end
-
     private
 
     # In MySQL 5.5+ error messages are always constructed server-side as UTF-8