RFR: JDK-8303742: CompletableFuture.orTimeout leaks if the future completes exceptionally [v3]

[Jaikiran Pai]

On Thu, 16 Mar 2023 21:25:44 GMT, Viktor Klang <duke at openjdk.org> wrote:

>> Addresses the situation where exceptional completion of `orTimeout`:ed CompletableFutures wouldn't cancel the timeout task which could lead to memory leaks if done frequently enough with long enough timeout durations.
>> 
>> Fix discussed with @DougLea
>
> Viktor Klang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Making the test for orTimeout+completeExceptionally only based on iterations and not duration.

Hello Viktor, the changes look good to me. Looking at the code, I see that this issue will also affect the `completeOnTimeout(...)` method on the `CompletableFuture`. Would you want to enhance the test to include a test for this method too? The following test method which tests this `completeOnTimeout()` reproduces the leak (and thus the OOM) without your fix:


@Test
    void testCompleteOnTimeoutWithCompleteExceptionallyDoesNotLeak() {
        var count = 0L;
        while(count < 2_000_000) {
            new CompletableFuture<>().completeOnTimeout(null, 12, TimeUnit.HOURS).completeExceptionally(new RuntimeException("This is fine"));
            ++count;

        }
    }

-------------

PR: https://git.openjdk.org/jdk/pull/13059