chainparams: Explicitly use uint16 for nDefaultPort #15586

Port numbers are 16-bit unsigned integers.

Could also update call sites?

Unless you switch the constructors to use member initizlizer lists with the "{}-syntax" that checks for overflows, I don't see how this adds any value.

Also, #8394 (comment)

sorry, NACK, I don't see the point, this doesn't improve the code in any user-visible way

utACK 7c6b079883b579b1973dd91df7b60bf95e85ef20. Code change itself looks good and is more clear and correct. Will happily defer to Marco/Wladimir on project management & prioritization, though, if this shouldn't be merged on those grounds.

utACK 7c6b079883b579b1973dd91df7b60bf95e85ef20 (agree with @ryanofsky)

@MarcoFalke You mean use member initializer lists for CChainParams?

w/re the parsing comment #8394 (comment), would @laanwj and @MarcoFalke be more inclined to merge if this PR added relevant ArgsManager changes? This would be usable for both -port and -rpcport I believe.

Just for some context, this was motivated by my looking at GetListenPort(), which I believe casts signed ints to unsigned shorts. I think pairing this change with an ArgsManager change with good parsing would make it worthwhile.

Also related: #14856 (review)

I believe it casts int64_t to unsigned short, but that should be fine as long as we check that the value is in range before the cast. No need to change the return type here.

This is just one of many cases where a 16-bit int type could cause problems, so I'm okay with fixing it for future portability. But I agree that if we do, we should fix the call sites too:

• GetListenPort (in net.cpp)
• CConnman::ConnectNode's default_port (in net.cpp)
• Lookup's portDefault, port (in netbase.cpp)
• • SplitHostPort's portOut (in util/strencodings.cpp)
• LookupNumeric's portDefault (in net.cpp)

I'll pick this back up someday. Feel free to grab it from me.

Removing up for grabs, as this is currently included in #21328.