net: WriteMsgUDPAddrPort should accept zero value destination addresses #74841
Description
Go version
all versions since go1.18
Output of go env in your module/workspace:
see aboveWhat did you do?
Call net.Dialer.DialContext to create a connected *net.UDPConn. Call WriteMsgUDPAddrPort on it with a zero value destination address.
What did you see happen?
WriteMsgUDPAddrPort fails with non-IPv6 address.
What did you expect to see?
WriteMsgUDPAddrPort should allow zero value addresses, just like how WriteMsgUDP allows nil addresses.
WriteMsgUDPAddrPort is used here instead of Write, because we need to send socket control messages together with the payload for UDP GSO.
This should be a straightforward fix. I'm sending a CL.