Use symbolic names for numeric replies where available

irclog.py

@@ -346,17 +346,17 @@ class IRCClientProtocol(asyncio.Protocol):
 				self.send(b'CAP END')
 		elif line.command == 'AUTHENTICATE' and line.params == ['+']:
 			self.send(b'AUTHENTICATE +')
-		elif line.command == '903': # SASL auth successful
+		elif line.command == ircstates.numerics.RPL_SASLSUCCESS:
 			self.authenticated = True
 			self.capReqsPending.remove('sasl')
 			if len(self.capReqsPending) == 0:
 				self.send(b'CAP END')
-		elif line.command in ('902', '904', '905', '906', '908'):
+		elif line.command in ('902', ircstates.numerics.ERR_SASLFAIL, ircstates.numerics.ERR_SASLTOOLONG, ircstates.numerics.ERR_SASLABORTED, ircstates.numerics.RPL_SASLMECHS):
 			self.logger.error('SASL error, terminating connection')
 			self.transport.close()
 
 		# NICK errors
-		elif line.command in ('431', '432', '433', '436'):
+		elif line.command in ('431', ircstates.numerics.ERR_ERRONEUSNICKNAME, ircstates.numerics.ERR_NICKNAMEINUSE, '436'):
 			self.logger.error(f'Failed to set nickname: {message!r}, terminating connection')
 			self.transport.close()
 
@@ -366,7 +366,7 @@ class IRCClientProtocol(asyncio.Protocol):
 			self.transport.close()
 
 		# JOIN errors
-		elif line.command in ('405', '471', '473', '474', '475'):
+		elif line.command in (ircstates.numerics.ERR_TOOMANYCHANNELS, ircstates.numerics.ERR_CHANNELISFULL, ircstates.numerics.ERR_INVITEONLYCHAN, ircstates.numerics.ERR_BANNEDFROMCHAN, ircstates.numerics.ERR_BADCHANNELKEY):
 			self.logger.error(f'Failed to join channel: {message!r}, terminating connection')
 			self.transport.close()
 
@@ -375,11 +375,11 @@ class IRCClientProtocol(asyncio.Protocol):
 			self.logger.error(f'Failed to part channel: {message!r}')
 
 		# JOIN/PART errors
-		elif line.command == '403':
+		elif line.command == ircstates.numerics.ERR_NOSUCHCHANNEL:
 			self.logger.error(f'Failed to join or part channel: {message!r}')
 
 		# Connection registration reply
-		elif line.command == '001':
+		elif line.command == ircstates.numerics.RPL_WELCOME:
 			self.logger.info('IRC connection registered')
 			if self.sasl and not self.authenticated:
 				self.logger.error('IRC connection registered but not authenticated, terminating connection')