6766844: ByteArrayInputStream#read with a byte array of length 0 not consistent with InputStream when at EOF

[bplb]

Modify java.io.ByteArrayInputStream methods read(byte[]) and read(byte[],int,int) to return zero per the InputStream specification when the byte array actual or specified length is zero.

---

Progress

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Issue

• JDK-6766844: ByteArrayInputStream#read with a byte array of length 0 not consistent with InputStream when at EOF

Reviewers

• Joe Wang (@JoeWang-Java - Reviewer) ⚠️ Review applies to 68b6f08
• Naoto Sato (@naotoj - Reviewer) ⚠️ Review applies to a53849a

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Webrevs

• 04: Full - Incremental (5435fe81)
• 03: Full - Incremental (a53849a2)
• 02: Full - Incremental (3152cdc7)
• 01: Full - Incremental (68b6f089)
• 00: Full (3ea4e18d)

[JoeWang-Java]

Looks good to me. Maybe add the bug id to the @bug tag of the test.

[openjdk]

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

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6766844: ByteArrayInputStream#read with a byte array of length 0 not consistent with InputStream when at EOF

Reviewed-by: joehw, naoto

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At the time when this comment was updated there had been 131 new commits pushed to the master branch:

• 5c08344: 8269678: Remove unimplemented and unused os::bind_to_processor()
• 83bce94: 8268457: XML Transformer outputs Unicode supplementary character incorrectly to HTML
• 1810b1c: 8269516: AArch64: Assembler cleanups
• a96012a: 8261495: Shenandoah: reconsider update references memory ordering
• 23d2996: 8269478: Shenandoah: gc/shenandoah/mxbeans tests should be more resilient
• a6b253d: 8269416: [JVMCI] capture libjvmci crash data to a file
• a0f32cb: 8268906: gc/g1/mixedgc/TestOldGenCollectionUsage.java assumes that GCs take 1ms minimum
• ee0247f: 8263461: jdk/jfr/event/gc/detailed/TestEvacuationFailedEvent.java uses wrong mechanism to cause evacuation failure
• 3ad20fc: 8269571: NMT should print total malloc bytes and invocation count
• b969136: 8245877: assert(_value != __null) failed: resolving NULL _value in JvmtiExport::post_compiled_method_load
• ... and 121 more: https://git.openjdk.java.net/jdk/compare/cd20c01942dd8559a31e51ef2a595c6eba44b8ad...master

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[bplb]

Yeah I overlooked adding the bug ID to the test.

[AlanBateman]

/csr

[openjdk]

@AlanBateman has indicated that a compatibility and specification (CSR) request is needed for this pull request.
@bplb please create a CSR request for issue JDK-6766844. This pull request cannot be integrated until the CSR request is approved.

[AlanBateman]

I realize I submitted this issue a long time ago but I think we have to proceed with caution as it is changing long standing behavior. Reading with len==0 will arise with code that is reading in a loop and the "previous read" completely fills the array and reads all remaining bytes. It's possible that there is existing code that will break with this change. I've added the "csr" label for now. If this changes goes ahead then it will need a release note too.

[bplb]

I had the same misgivings after creating this PR and thought that a CSR would be in order.

[bplb]

CSR JDK-8269399 created.

[RogerRiggs]

The spec for ByteArrayInputStream.read(byte[], off, len) is pretty specific about returning -1 if there is nothing to read.
The spec inherited from InputStream doesn't supercede javadoc of BAIS.
If the implementation is going to change then the spec will need to change too.
It seems safer to document the inconsistency and avoid the risk of infinite loops.

[bplb]

@RogerRiggs I agree.

[naotoj]

Agree that clarifying the spec would be a much safer solution.

[bplb]

CSR revised to match.

[bplb]

This PR has been superseded by the JDK 17 PR 189.