8231259: (dc) DatagramChannel::disconnect re-binds socket to the wildcard address (macOS)

[Chris Hegarty]

> On 19 Nov 2019, at 10:44, Daniel Fuchs <daniel.fuchs at oracle.com> wrote:
> 
> Hi Chris,
> 
> On 19/11/2019 09:54, Chris Hegarty wrote:
>>>> In case repairSocket() later fails. Although we already specified
>>>> that "the socket is an unspecified state", it would leave
>>>> the socket is in an unspecified state closer to what it was
>>>> before the fix.
>>> That is a good point, there should be a try-finally around the repair so that the localAddress is set even when it fails.
>> 4) Given the potential for failure at any point during “repairing”, it is not just "the channel's socket” that "may be left in an unspecified state”, but the channel itself ( it may be blocking or non-blocking, bound or not-bound, some options set some not, etc ).
> 
> How so? Unless I miss something these all pertain to the
> underlying channel's socket - not to the channel itself.

For example, if the “repairing” fails to re-bind to the original port then an exception will be thrown from repairSocket. Subsequently, the finally block will attempt to retrieve the local address ( which I guess will also fail with an exception ( Ugh! this will suppress the re-binding exception ) ). Now both 1) the channel’s socket is in an unspecified state, and 2) the channel is in an unspecified state. What will getLocalAddress return? My point is that the apiNote is overly pendantic about *just* the channel’s socket being in an unspecified state. It is not *just* the channel’s socket, it is the channel itself too.
> And the recommendation to close the channel if disconnect fails
> still holds.

Yes, the recommendation still holds.

-Chris.