JDK-8303742: CompletableFuture.orTimeout leaks if the future completes exceptionally

[viktorklang-ora]

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

---

Progress

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Issue

• JDK-8303742: CompletableFuture.orTimeout leaks if the future completes exceptionally

Reviewers

• Jaikiran Pai (@jaikiran - Reviewer) ⚠️ Review applies to e2c1c366
• Alan Bateman (@AlanBateman - Reviewer)

Reviewing

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[openjdk]

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Webrevs

• 05: Full - Incremental (80680bee)
• 04: Full - Incremental (71b67aea)
• 03: Full - Incremental (e2c1c366)
• 02: Full - Incremental (05619280)
• 01: Full - Incremental (15e8fcc2)
• 00: Full (d46a6bed)

[AlanBateman]

The update to CF looks good. The test looks okay it as it fails in a few seconds without the change.

[jaikiran]

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;

        }
    }

[viktorklang-ora]

@jaikiran Excellent catch, you're right—I've added such a test case as well to this PR. 👍

[viktorklang-ora]

@jaikiran @pavelrappo Copyright year fixed as well 👍

[jaikiran]

Thank you Viktor for the updates. This looks good to me.

[openjdk]

@viktorklang-ora This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8303742: CompletableFuture.orTimeout leaks if the future completes exceptionally

Reviewed-by: jpai, alanb

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 61 new commits pushed to the master branch:

• 652bda0: 8304411: Remove unused CardTable::clear
• 4505670: 8304174: Remove delays from httpserver tests
• c09f83e: 8304293: RISC-V: JDK-8276799 missed atomic intrinsic support for C1
• e339e18: 7016187: javac -h could generate conflict .h for inner class and class name with '_'
• 033c0b1: 8304437: ProblemList com/sun/jdi/ThreadMemoryLeadTest.java with ZGC
• 7503ecc: 8304138: [JVMCI] Test FailedSpeculation existence before appending.
• f8482c2: 8297638: Memory leak in case of many started-dead threads
• c56f011: 8298995: tools/jpackage/share/AddLauncherTest.java#id1 failed "AddLauncherTest.test; checks=53"
• 254288a: 8014021: TreeMaker.Params behaves inconsistently when the owning method has the same number of parameters as the number of parameter types requested
• 8f5bb53: 8015831: Add lint check for calling overridable methods from a constructor
• ... and 51 more: https://git.openjdk.org/jdk/compare/10f16746254ce62031f40ffb0f49f22e81cbe631...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

As you do not have Committer status in this project an existing Committer must agree to sponsor your change. Possible candidates are the reviewers of this PR (@jaikiran, @AlanBateman) but any other Committer may sponsor as well.

➡️ To flag this PR as ready for integration with the above commit message, type /integrate in a new comment. (Afterwards, your sponsor types /sponsor in a new comment to perform the integration).

[viktorklang-ora]

/integrate

[openjdk]

@viktorklang-ora
Your change (at version 80680be) is now ready to be sponsored by a Committer.

[jaikiran]

Hello Viktor, I'll sponsor this shortly. It's my understanding that changes to these classes are also expected to be synced to the jsr166 repo that Doug maintains. From the description in this PR, I'm guessing that Doug will be doing this change in the jsr166 repo as well?

[viktorklang-ora]

I just synced up with @DougLea—I'll let him decide how to handle it. :)

[jaikiran]

/sponsor

[openjdk]

Going to push as commit ded6a81.
Since your change was applied there have been 61 commits pushed to the master branch:

• 652bda0: 8304411: Remove unused CardTable::clear
• 4505670: 8304174: Remove delays from httpserver tests
• c09f83e: 8304293: RISC-V: JDK-8276799 missed atomic intrinsic support for C1
• e339e18: 7016187: javac -h could generate conflict .h for inner class and class name with '_'
• 033c0b1: 8304437: ProblemList com/sun/jdi/ThreadMemoryLeadTest.java with ZGC
• 7503ecc: 8304138: [JVMCI] Test FailedSpeculation existence before appending.
• f8482c2: 8297638: Memory leak in case of many started-dead threads
• c56f011: 8298995: tools/jpackage/share/AddLauncherTest.java#id1 failed "AddLauncherTest.test; checks=53"
• 254288a: 8014021: TreeMaker.Params behaves inconsistently when the owning method has the same number of parameters as the number of parameter types requested
• 8f5bb53: 8015831: Add lint check for calling overridable methods from a constructor
• ... and 51 more: https://git.openjdk.org/jdk/compare/10f16746254ce62031f40ffb0f49f22e81cbe631...master

Your commit was automatically rebased without conflicts.

[openjdk]

@jaikiran @viktorklang-ora Pushed as commit ded6a81.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.