RFR: 8299813: java/nio/channels/DatagramChannel/Disconnect.java fails with jtreg test timeout due to lost datagram

[Daniel Fuchs]

On Fri, 28 Jun 2024 09:50:50 GMT, Aleksei Efimov <aefimov at openjdk.org> wrote:

>> Please find here a simple fix to solve an intermittent failure in  java/nio/channels/DatagramChannel/Disconnect.java
>> 
>> On some platform, the underlying system may allow two datagram sockets to bind to the same port, if one of them uses the wildcard address and the other doesn't.
>> 
>> What happens here is that during DC:connect, if the socket is unbound, it will get bound to the wildcard.
>> From time to time, this results into binding to the same port that the `server` is using in the test.
>> When that happens, datagram sent to the connected server may get misrouted and may not get delivered, and the call server::receive may block forever.
>> 
>> This change does two things: 
>>   1. explicitly  bind the server to the loopback address instead of InetAddress.getLocalHost()
>>   2. skip the receive part of the test if the client local address obtained after connecting uses the same port than the server. 
>>   
>> This is rare, and skipping the receive part in that case does not invalidate the test.
>
> The changes look good to me.

Thanks @AlekseiEfimov ! If I don't receive further feedback I will integrate shortly

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PR Comment: https://git.openjdk.org/jdk/pull/19908#issuecomment-2196577027