8335766: Switch case with pattern matching and guard clause compiles inconsistently

[lahodaj]

When javac parser see a case label, it needs to disambiguate between expressions (constant labels) and patterns. But, for code like:

case R(int x) when (x > 0)

the parser will try to parse the label as an expression, which is obviously not correct. The problem is that it does not disambiguate before when, and there indeed is an expression after when.

The proposal is to disambiguate as a pattern once there is when after a closing parenthesis at the top-level. This should prevent the code to even look at the when expression

---

Progress

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Issue

• JDK-8335766: Switch case with pattern matching and guard clause compiles inconsistently (Bug - P4)

Reviewers

• Aggelos Biboudis (@biboudis - Reviewer)

Reviewing

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👋 Welcome back jlahoda! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@lahodaj 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:

8335766: Switch case with pattern matching and guard clause compiles inconsistently

Reviewed-by: abimpoudis

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 9 new commits pushed to the master branch:

• 8f62f31: 8335906: [s390x] Test Failure: GTestWrapper.java
• 2a29647: 8334777: Test javax/management/remote/mandatory/notif/NotifReconnectDeadlockTest.java failed with NullPointerException
• 564a72e: 8335955: JDK-8335742 wrongly used a "JDK-" prefix in the problemlist bug number
• 9c7a6ea: 8312125: Refactor CDS enum class handling
• bb1f8a1: 8335904: Fix invalid comment in ShenandoahLock
• babf6df: 8334757: AssertionError: Missing type variable in where clause
• 3733fe3: 8335789: [TESTBUG] XparColor.java test fails with Error. Parse Exception: Invalid or unrecognized bugid: @
• 3a87eb5: 8335126: Shenandoah: Improve OOM handling
• 284671a: 8335449: runtime/cds/DeterministicDump.java fails with File content different at byte ...

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
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[openjdk]

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[mlbridge]

Webrevs

• 00: Full (139bf1db)

[biboudis]

Looks good.

[lahodaj]

/integrate

[openjdk]

Going to push as commit 537d20a.
Since your change was applied there have been 17 commits pushed to the master branch:

• a44b60c: 8335778: runtime/ClassInitErrors/TestStackOverflowDuringInit.java fails on ppc64 platforms after JDK-8334545
• b5909ca: 8323242: Remove vestigial DONT_USE_REGISTER_DEFINES
• dcf4e0d: 8335966: Remove incorrect problem listing of java/lang/instrument/NativeMethodPrefixAgent.java in ProblemList-Virtual.txt
• 1472124: 8333364: Minor cleanup could be done in com.sun.crypto.provider
• 7e11fb7: 8335688: Fix -Wzero-as-null-pointer-constant warnings from fflush calls in jvmti tests
• 531a6d8: 8335911: Document ccls indexer in doc/ide.md
• 0e0dfca: 8330806: test/hotspot/jtreg/compiler/c1/TestLargeMonitorOffset.java fails on ARM32
• f3ff4f7: 8335882: platform/cgroup/TestSystemSettings.java fails on Alpine Linux
• 8f62f31: 8335906: [s390x] Test Failure: GTestWrapper.java
• 2a29647: 8334777: Test javax/management/remote/mandatory/notif/NotifReconnectDeadlockTest.java failed with NullPointerException
• ... and 7 more: https://git.openjdk.org/jdk/compare/a9b7f42f29120a3cca0d341350ff03cae485e68b...master

Your commit was automatically rebased without conflicts.

[openjdk]

@lahodaj Pushed as commit 537d20a.

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

[lahodaj]

/backport jdk jdk23

[openjdk]

@lahodaj the backport was successfully created on the branch backport-lahodaj-537d20af-jdk23 in my personal fork of openjdk/jdk. To create a pull request with this backport targeting openjdk/jdk:jdk23, just click the following link:

➡️ Create pull request

The title of the pull request is automatically filled in correctly and below you find a suggestion for the pull request body:

Hi all,

This pull request contains a backport of commit 537d20af from the openjdk/jdk repository.

The commit being backported was authored by Jan Lahoda on 10 Jul 2024 and was reviewed by Aggelos Biboudis.

Thanks!

If you need to update the source branch of the pull then run the following commands in a local clone of your personal fork of openjdk/jdk:

$ git fetch https://github.com/openjdk-bots/jdk.git backport-lahodaj-537d20af-jdk23:backport-lahodaj-537d20af-jdk23
$ git checkout backport-lahodaj-537d20af-jdk23
# make changes
$ git add paths/to/changed/files
$ git commit --message 'Describe additional changes made'
$ git push https://github.com/openjdk-bots/jdk.git backport-lahodaj-537d20af-jdk23