clarify that servers SHOULD send RPL_ENDOFWHOIS

[slingamn]

From discussion on Libera-Chat/sable#101

cc @progval

[progval]

@spb pointed out that RPL_ENDOFWHOIS is not sent after ERR_NEEDMOREPARAMS

[tommyrot]

RPL_ENDOFWHOIS is not sent after ERR_NEEDMOREPARAMS

Not after ERR_NONICKNAMEGIVEN either.

[SadieCat]

At least in our implementation we only send ERR_ENDOFWHOIS after a well formed WHOIS request. So you'll only get it after one ERR_NOSUCHNICK or one or more RPL_WHOIS* numerics. I don't think we need to worry too much about clients sending broken responses imo.

[slingamn]

Thanks, I updated this to clarify that the SHOULD only applies when the client's message is well-formed.

[progval]

Can/shoukd we also keep it a MUST when there is no <target> (ie. local whois), or should we leave this implementation-specific?

[slingamn]

I don't see a compelling reason to change it right now (we would presumably have to do a more detailed investigation of server behaviors, also it's not clear to me that a hard guarantee here would be helpful to clients --- as in the debate over labeled-response, clients should probably implement a timeout regardless?)

I would support opening a follow-up thread to discuss this.