8308399: Recommend --release when -source and -target are misused

[lahodaj]

This patch modifies some warning and error messages to recommend --release more loudly. Please see details below.

Note that while the patch changes compiler.warn.source.target.conflict to compiler.err.source.target.conflict, there is no change in the set of accepted options and their combinations. This used to behave as an error, and still behaves as an error. So this patch only changes the console text from warning: ... to error: ....

+ javac -source 8 /tmp/Test.java
warning: [options] bootstrap class path is not set in conjunction with -source 8
  not setting the bootstrap class path may lead to class files that cannot run on JDK 8
    --release 8 is recommended instead of -source 8 because it sets the bootstrap class path automatically
warning: [options] source value 8 is obsolete and will be removed in a future release
warning: [options] To suppress warnings about obsolete options, use -Xlint:-options.
3 warnings

+ javac -source 8 -target 8 /tmp/Test.java
warning: [options] bootstrap class path is not set in conjunction with -source 8
  not setting the bootstrap class path may lead to class files that cannot run on JDK 8
    --release 8 is recommended instead of -source 8 -target 8 because it sets the bootstrap class path automatically
warning: [options] source value 8 is obsolete and will be removed in a future release
warning: [options] target value 8 is obsolete and will be removed in a future release
warning: [options] To suppress warnings about obsolete options, use -Xlint:-options.
4 warnings

+ javac -source 11 /tmp/Test.java
warning: [options] location of system modules is not set in conjunction with -source 11
  not setting the location of system modules may lead to class files that cannot run on JDK 11
    --release 11 is recommended instead of -source 11 because it sets the location of system modules automatically
1 warning

+ javac -source 11 -target 11 /tmp/Test.java
warning: [options] location of system modules is not set in conjunction with -source 11
  not setting the location of system modules may lead to class files that cannot run on JDK 11
    --release 11 is recommended instead of -source 11 -target 11 because it sets the location of system modules automatically
1 warning

+ javac -target 17 -source 11 /tmp/Test.java
warning: [options] location of system modules is not set in conjunction with -source 11
  not setting the location of system modules may lead to class files that cannot run on JDK 11
    --release 11 is recommended instead of -source 11 -target 17 because it sets the location of system modules automatically
1 warning

+ javac -target 8 -source 11 /tmp/Test.java
error: specified target release 8 is too old for the specified source release 11
  --release 8 is recommended when compiling code to run on JDK 8

+ javac -target 8 /tmp/Test.java
error: specified target release 8 is too old for the default source release 22
  --release 8 is recommended when compiling code to run on JDK 8

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue

Issue

• JDK-8308399: Recommend --release when -source and -target are misused (Enhancement - P4)

Reviewers

• Vicente Romero (@vicente-romero-oracle - Reviewer)

Reviewing

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[openjdk]

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[vicente-romero-oracle]

looks sensible

[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:

8308399: Recommend --release when -source and -target are misused

Reviewed-by: vromero

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 352 new commits pushed to the master branch:

• dc256fb: 8320061: [nmt] Multiple issues with peak accounting
• adad132: 8320767: Use := wherever possible in spec.gmk.in
• 69c0b24: 8320714: java/util/Locale/LocaleProvidersRun.java and java/util/ResourceBundle/modules/visibility/VisibilityTest.java timeout after passing
• 66ae6d5: 8320899: Select the correct Makefile when running make in build directory
• ebbef62: 8320769: Remove ill-adviced "make install" target
• 86bb804: 8320863: dsymutil command leaves around temporary directories
• db7fedf: 8320358: GHA: ignore jdk* branches
• e33b6c1: 8319437: NMT should show library names in call stacks
• 2fae07f: 8319311: JShell Process Builder should be configurable
• 63ad868: 8319668: Fixup of jar filename typo in BadFactoryTest.sh
• ... and 342 more: https://git.openjdk.org/jdk/compare/75ce02fe74e1232bfa8d72b4fdad82ed938ef957...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.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[lahodaj]

/integrate

[openjdk]

Going to push as commit 65dfcae.
Since your change was applied there have been 366 commits pushed to the master branch:

• 335f5db: 8320911: RISC-V: Enable hotspot/jtreg/compiler/intrinsics/chacha/TestChaCha20.java
• 77d604a: 8319373: Serial: Refactor dirty cards scanning during Young GC
• 38cfb22: 8318706: Implement JEP 423: Region Pinning for G1
• e44d4b2: 8320858: Move jpackage tests to tier3
• 5dcf3a5: 8320715: Improve the tests of test/hotspot/jtreg/compiler/intrinsics/float16
• 78b6c2b: 8320898: exclude compiler/vectorapi/reshape/TestVectorReinterpret.java on ppc64(le) platforms
• 9a6ca23: 8320918: Fix errors in the built-in Catalog implementation
• 5e1b771: 8316422: TestIntegerUnsignedDivMod.java triggers "invalid layout" assert in FrameValues::validate
• a657aa3: 8320681: [macos] Test tools/jpackage/macosx/MacAppStoreJlinkOptionsTest.java timed out on macOS
• 3ccd02f: 8320379: C2: Sort spilling/unspilling sequence for better ld/st merging into ldp/stp on AArch64
• ... and 356 more: https://git.openjdk.org/jdk/compare/75ce02fe74e1232bfa8d72b4fdad82ed938ef957...master

Your commit was automatically rebased without conflicts.

[openjdk]

@lahodaj Pushed as commit 65dfcae.

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