8317522: Test logic for BODY_CF in AbstractThrowingSubscribers.java is wrong

[dfuch]

The AbstractThrowingSubscribers.java test class makes the assumption that the HttpClient will cancel a request if the body CompletableFuture returned by a BodySubscriber::getBody is completed exceptionally. This assumption is wrong. Indeed, it should be the responsibility of the custom subscriber to cancel its subscription, or not, in such a case, as whether to cancel or not depends on the semantic the subscriber assigns to such a body.

The issue can be observed by modifying the test to send a longer response split in several chunks: with such a configuration, and using streaming body subscribers, such as ofInputStream, the test will fail waiting for the HttpClient to be garbaged collected, as the response data will not get pulled and the underlying exchange will never terminate. Though changing the HttpClient code to forcefully cancel the subscription (or the exchange) in such a case would "work", it does not seem desirable: it would introduce a change of behavior that might cause existing applications to fail, and there may be cases where a custom subscriber may legitimately want to complete its body CF exceptionally while still continuing to parse the body bytes. Whether to choose to cancel the subscription or not should solely depend on the logic of the custom subscriber.

The test logic is now modified to reflect this. Commenting the line that cancels the subscription in ThrowingBodySubscriber::getBody would now make the test fail. The test was previously passing "by chance" because the whole response was contained in a single DataFrame (or ByteBuffer for HTTP/1.1).

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Issue

• JDK-8317522: Test logic for BODY_CF in AbstractThrowingSubscribers.java is wrong (Bug - P4)

Reviewers

• Daniel Jeliński (@djelinski - Reviewer)

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[djelinski]

LGTM. Thanks!

[openjdk]

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

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

8317522: Test logic for BODY_CF in AbstractThrowingSubscribers.java is wrong

Reviewed-by: djelinski

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At the time when this comment was updated there had been 8 new commits pushed to the master branch:

• c6c69b5: 8314654: Metaspace: move locking out of MetaspaceArena
• 3105538: 8316146: Open some swing tests 4
• 36314a9: 8267509: Improve IllegalAccessException message to include the cause of the exception
• ddacf92: 8305765: CompressedClassPointers.java is unreliable due to ASLR
• 4195246: 8317354: Serial: Move DirtyCardToOopClosure to gc/serial folder
• 0a3a925: 8316414: C2: large byte array clone triggers "failed: malformed control flow" assertion failure on linux-x86
• b0d6c84: 8316396: Endless loop in C2 compilation triggered by AddNode::IdealIL
• a8549b6: 8280120: [IR Framework] Add attribute to @ir to enable/disable IR matching based on the architecture

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[dfuch]

/integrate

[openjdk]

Going to push as commit 4c5b66d.
Since your change was applied there have been 12 commits pushed to the master branch:

• 42be238: 8316523: Relativize esp in interpreter frames (PowerPC only)
• a250ae4: 8317039: Enable specifying the JDK used to run jtreg
• 1ed9c76: 8309204: Obsolete DoReserveCopyInSuperWord
• 3630af2: 8316594: C2 SuperWord: wrong result with hand unrolled loops
• c6c69b5: 8314654: Metaspace: move locking out of MetaspaceArena
• 3105538: 8316146: Open some swing tests 4
• 36314a9: 8267509: Improve IllegalAccessException message to include the cause of the exception
• ddacf92: 8305765: CompressedClassPointers.java is unreliable due to ASLR
• 4195246: 8317354: Serial: Move DirtyCardToOopClosure to gc/serial folder
• 0a3a925: 8316414: C2: large byte array clone triggers "failed: malformed control flow" assertion failure on linux-x86
• ... and 2 more: https://git.openjdk.org/jdk/compare/9718f490fb76f6712ac8f9c7f5248ca10bf83e6f...master

Your commit was automatically rebased without conflicts.

[openjdk]

@dfuch Pushed as commit 4c5b66d.

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