8254784: javac should reject records with @SafeVarargs applied to varargs record component

[vicente-romero-oracle]

Please review this fix for issue [1]. This is the background, for a record defined like:

record R(@SafeVarargs String... s) {}

an the following accessor will be generated:

`@SafeVararags public String[] s() { return s; }`

this code is incorrect as the accessor is not a varargs method. But still the compiler is not generating a compiler error. The reason for this is that the method defining the accessor is not generated until the compiler get to its backend phase (at Lower to be more specific) and the check for incorrect @SafeVarargs use in the compiler happen before that, in Attr.

We decided to do not generate record related code until late phases in order to avoid generating code in the compiler frontend and because if code is generated in early stages then APs could see ASTs not created from user defined code.

The proposed fix is to issue an error as soon as the compiler finds out that the @SafeVarargs annotation is applied to a compiler generated accessor because in other case the compiler would be forced to generate incorrect code.

TIA for the reviews,
Vicente

[1] https://bugs.openjdk.java.net/browse/JDK-8254784

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Progress

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Testing

	Linux x64	Linux x86	Windows x64	macOS x64
Build	✔️ (5/5 passed)	✔️ (2/2 passed)	✔️ (2/2 passed)	✔️ (2/2 passed)
Test (tier1)	❌ (1/9 failed)	❌ (1/9 failed)	❌ (1/9 failed)	❌ (1/9 failed)

Failed test tasks

• Linux x64 (langtools/tier1)
• Linux x86 (langtools/tier1)
• Windows x64 (langtools/tier1)
• macOS x64 (langtools/tier1)

Issue

• JDK-8254784: javac should reject records with @SafeVarargs applied to varargs record component

Reviewers

• Maurizio Cimadamore (@mcimadamore - Reviewer)

Download

$ git fetch https://git.openjdk.java.net/jdk pull/690/head:pull/690
$ git checkout pull/690

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[mlbridge]

Webrevs

• 01: Full (744d135)
• 00: Full (6d3dcd0)

[mcimadamore]

Seems sensible. A possible alternative would be to err immediately when we see (e.g. in TypeEnter?) that a record header contains a SafeVarargs annotation, in which case we know we can't support it.

[openjdk]

@vicente-romero-oracle This change now passes all automated pre-integration checks.

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

8254784: javac should reject records with @SafeVarargs applied to varargs record component

Reviewed-by: mcimadamore

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At the time when this comment was updated there had been 105 new commits pushed to the master branch:

• e9956fe: 8256127: Add cross-compiled foreign architectures builds to submit workflow
• c8dd0b5: 8256320: ZGC: Update zDebug to support UseCompressedClassPointers
• 5973e91: 8253005: Add @throws IOException in javadoc for HttpEchange.sendResponseHeaders
• 8c31bd2: 8256275: Optimized build is broken
• b0c28fa: 8256011: Shenandoah: Don't resurrect finalizably reachable objects
• 41139e3: 8255964: Add all details to jstack log in jtreg timeout handler
• b4d0186: 8253525: Implement getInstanceSize/sizeOf intrinsics
• ea576dd: 8254887: C2: assert(cl->trip_count() > 0) failed: peeling a fully unrolled loop
• 05b8245: 8256290: javac/lambda/T8031967.java fails with StackOverflowError on x86_32
• c3139ab: 8256220: C1: x86_32 fails with -XX:UseSSE=1 after JDK-8210764 due to mishandled lir_neg
• ... and 95 more: https://git.openjdk.java.net/jdk/compare/a50fdd5484ee2ac78cc54dd68ea824ab5659d08e...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.

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[vicente-romero-oracle]

thanks for the approval, yes we could have done what you are proposing too

[vicente-romero-oracle]

/integrate

[openjdk]

@vicente-romero-oracle Since your change was applied there have been 498 commits pushed to the master branch:

• dcf63f8: 8257788: Class fields could be local in the SunJSSE provider
• d29c78d: 8257679: Improved unix compatibility layer in Windows build (winenv)
• 74be819: 8257517: LogCompilation: Add -z to the help messages
• 2c04fc0: 8257037: No javac warning when calling deprecated constructor with diamond
• 46b35ac: 8257798: [PPC64] undefined reference to Klass::vtable_start_offset()
• ecd7e47: 8257793: Shenandoah: SATB barrier should only filter out already strongly marked oops
• e08b9ed: 8257820: Remove gc/ergonomics/TestMinHeapSize.java as it is too brittle
• 637b0c6: 8246778: Compiler implementation for Sealed Classes (Second Preview)
• 09707dd: 8252807: The jdk.jfr.Recording.getStream does not work when toDisk is disabled
• 04ce8e3: 8257184: Upstream 8252504: Add a method to MemoryLayout which returns a offset-computing method handle
• ... and 488 more: https://git.openjdk.java.net/jdk/compare/a50fdd5484ee2ac78cc54dd68ea824ab5659d08e...master

Your commit was automatically rebased without conflicts.

Pushed as commit b4b9828.

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