JDK-8273452: DocTrees.getDocCommentTree should be specified as idempotent

[hns]

Please review a doc-only change to add implementation notes to the DocTrees.getDocCommentTree methods, some of which return the same DocCommentTree instance on repeated invocation and some don't. I decided to use @implNote instead of @implSpec as usually I wouldn't expect object identity to be part of a Java API specification.

I verified the described behavior using code analysis and enhancing existing tests. The latter are not included in the commit as this is a noreg-doc issue.

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Progress

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Issue

• JDK-8273452: DocTrees.getDocCommentTree should be specified as idempotent

Reviewers

• Jonathan Gibbons (@jonathan-gibbons - Reviewer) ⚠️ Review applies to f69a105

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[openjdk]

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[mlbridge]

Webrevs

• 01: Full - Incremental (66cbd42b)
• 00: Full (f69a1052)

[jonathan-gibbons]

I guess it's a gray area whether it should be an implSpec or an implNote.

It is a relatively important aspect of the API, because the operations are expensive, and even cause some downstream caching.

For now, it's enough that it is noted in some fashion.

As a general style note, I would suggest a blank line before each implNote, and change "The implementation of this method" to either "The default implementation of this method" or just "This implementation".

[openjdk]

@hns 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:

8273452: DocTrees.getDocCommentTree should be specified as idempotent

Reviewed-by: jjg

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 52 new commits pushed to the master branch:

• 06b4d49: 8278344: sun/security/pkcs12/KeytoolOpensslInteropTest.java test fails because of different openssl output
• 8f969a1: 8278930: javac tries to compile a file twice via PackageElement.getEnclosedElements
• 642ab34: 8278373: JavacTrees.searchMethod finds incorrect match
• d65c665: 8279527: Dereferencing segments backed by different scopes leads to pollution
• 967ef0c: 8278020: ~13% variation in Renaissance-Scrabble
• 7c792f2: 8279333: Some JFR tests do not accept 'GCLocker Initiated GC' as a valid GC Cause
• 564c8c6: 8279529: ProblemList java/nio/channels/DatagramChannel/ManySourcesAndTargets.java on macosx-aarch64
• 590fa9d: 8278612: [macos] test/jdk/java/awt/dnd/RemoveDropTargetCrashTest crashes with VoiceOver on macOS
• 5cd9515: 8279525: ProblemList java/awt/GraphicsDevice/CheckDisplayModes.java on macosx-aarch64
• 9d43d25: 8278897: Alignment of heap segments is not enforced correctly
• ... and 42 more: https://git.openjdk.java.net/jdk18/compare/e82310f3605b37519129ea34b2a6f99ee3ccc63a...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.

[hns]

/integrate

[openjdk]

Going to push as commit 354c904.
Since your change was applied there have been 52 commits pushed to the master branch:

• 06b4d49: 8278344: sun/security/pkcs12/KeytoolOpensslInteropTest.java test fails because of different openssl output
• 8f969a1: 8278930: javac tries to compile a file twice via PackageElement.getEnclosedElements
• 642ab34: 8278373: JavacTrees.searchMethod finds incorrect match
• d65c665: 8279527: Dereferencing segments backed by different scopes leads to pollution
• 967ef0c: 8278020: ~13% variation in Renaissance-Scrabble
• 7c792f2: 8279333: Some JFR tests do not accept 'GCLocker Initiated GC' as a valid GC Cause
• 564c8c6: 8279529: ProblemList java/nio/channels/DatagramChannel/ManySourcesAndTargets.java on macosx-aarch64
• 590fa9d: 8278612: [macos] test/jdk/java/awt/dnd/RemoveDropTargetCrashTest crashes with VoiceOver on macOS
• 5cd9515: 8279525: ProblemList java/awt/GraphicsDevice/CheckDisplayModes.java on macosx-aarch64
• 9d43d25: 8278897: Alignment of heap segments is not enforced correctly
• ... and 42 more: https://git.openjdk.java.net/jdk18/compare/e82310f3605b37519129ea34b2a6f99ee3ccc63a...master

Your commit was automatically rebased without conflicts.

[openjdk]

@hns Pushed as commit 354c904.

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