Fix the behavior of `Socket.address`

[brianquinlan]

Change

Socket.address currently returns the same InternetAddress as Socket.remoteAddress. Instead, it should return the local address that the Socket was bound to.

The original bug is: dart:io, address getter of Socket returns wrong address.

Rationale

The current behavior is not useful. Instead, two connected sockets should have a relationship like:

Expect.equals(clientSocket.address, serverSocket.remoteAddress);
Expect.equals(clientSocket.remoteAddress, serverSocket.address);

There is a work-in-progress change in Gerrit.

Impact

It is hard to know how much existing code this will break. It does not break any Google tests and I would guess that it does not break much existing code.

Mitigation

Users can switch their code to use Socket.remoteAddress instead of Socket.address if they want the remote socket binding.

[itsjustkevin]

@vsmenon @Hixie @grouma we have another breaking change request. Could you take a look?

[grouma]

Since there is an easy mitigation and no broken Google tests this is probably fine. I do have concerns that some of our developer tools that historically don't have great test coverage could be broken. For example, Dart Dev Runner, Bolt, package:webdev etc.

[Hixie]

SGTM. Might be worth looking at https://github.com/dart-lang/sdk/issues/12693 at the same time.

[brianquinlan]

Ah, I noticed #12693 as well. I think that fixing just that part might be non-breaking but I'll take a look.

[vsmenon]

lgtm

[itsjustkevin]

Marking this as approved.

[itsjustkevin]

@brianquinlan is this work still in flight? Is it planned for Dart 3?

[BBUBBA]

The bug that happened in 2019, still hasn't been fixed..

Can't P2P UDP HolePunch.

plz.. Update. Thank you !!!