JDK-8280550: SplittableRandom#nextDouble(double,double) can return result >= bound

[jddarcy]

Use floating-point library methods to nudge down the result if needed. The nextAfter(r, origin) call return the next value in the direction of origin, handling cases for negative values, etc.

Changing to call nextDown for the origin is bounded at zero is just a refactoring that is clearer to read IMO.

The regression test fails on an unpatched JDK.

---

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Issue

• JDK-8280550: SplittableRandom#nextDouble(double,double) can return result >= bound

Reviewers

• Jim Laskey (@JimLaskey - Reviewer)
• Paul Sandoz (@PaulSandoz - Reviewer)

Reviewing

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[openjdk]

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[mlbridge]

Webrevs

• 00: Full (9d52afe3)

[JimLaskey]

LGTM

[openjdk]

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

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

8280550: SplittableRandom#nextDouble(double,double) can return result >= bound

Reviewed-by: jlaskey, psandoz

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At the time when this comment was updated there had been 9 new commits pushed to the master branch:

• f34f8d4: 8277983: Remove unused fields from sun.net.www.protocol.jar.JarURLConnection
• a07e19d: 8278410: Improve argument processing around UseHeavyMonitors
• ed0df2f: 8268033: compiler/intrinsics/bmi/verifycode/BzhiTestI2L.java fails with "fatal error: Not compilable at tier 3: CodeBuffer overflow"
• c180070: 8280373: Update Xalan serializer / SystemIDResolver to align with JDK-8270492
• a24f44d: 8280526: x86_32 Math.sqrt performance regression with -XX:UseSSE={0,1}
• e72eefd: 8280531: Remove unused DeferredCloseInputStream
• 2c64a7f: 8280374: G1: Remove unnecessary prev bitmap mark
• a183bfb: 8280377: MethodHandleProxies does not correctly invoke default methods with varags
• 2eab86b: 8213905: reflection not working for type annotations applied to exception types in the inner class constructor

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

/integrate

[openjdk]

Going to push as commit 0c42e43.
Since your change was applied there have been 14 commits pushed to the master branch:

• a5a11f1: Merge
• ef08e2c: 8280592: Small javadoc tweaks to foreign API
• b8365aa: 8268978: Document the javadoc software stack
• 4b2370e: 8279294: NonblockingQueue::try_pop may improperly indicate queue is empty
• e1d8f55: 8280402: Add new convenience forms to HtmlTree
• f34f8d4: 8277983: Remove unused fields from sun.net.www.protocol.jar.JarURLConnection
• a07e19d: 8278410: Improve argument processing around UseHeavyMonitors
• ed0df2f: 8268033: compiler/intrinsics/bmi/verifycode/BzhiTestI2L.java fails with "fatal error: Not compilable at tier 3: CodeBuffer overflow"
• c180070: 8280373: Update Xalan serializer / SystemIDResolver to align with JDK-8270492
• a24f44d: 8280526: x86_32 Math.sqrt performance regression with -XX:UseSSE={0,1}
• ... and 4 more: https://git.openjdk.java.net/jdk/compare/295c0474c43484e793b67a70af316aaae49fe361...master

Your commit was automatically rebased without conflicts.

[openjdk]

@jddarcy Pushed as commit 0c42e43.

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