GH-1196: Write NO_COMPRESSION_LENGTH sentinel for empty buffers in compress() - #1248
Open
PG1204 wants to merge 1 commit into
Open
GH-1196: Write NO_COMPRESSION_LENGTH sentinel for empty buffers in compress()#1248PG1204 wants to merge 1 commit into
PG1204 wants to merge 1 commit into
Conversation
PG1204
requested review from
jbonofre,
laurentgo,
lidavidm and
wgtmac
as code owners
July 24, 2026 17:10
This comment has been minimized.
Copy link
Copy Markdown
Author
Notes for reviewers
|
Sorry, something went wrong.
lidavidm
approved these changes
Jul 27, 2026
lidavidm
left a comment
Copy link
Copy Markdown
Member
There was a problem hiding this comment.
Seems reasonable to me.
Sorry, something went wrong.
Copy link
Copy Markdown
Member
|
@PG1204 can you rebase to pick up CI fixes? |
Sorry, something went wrong.
PG1204
force-pushed
the
gh-1196-empty-buffer-compression
branch
from
547cec8 to
9c7c63d
Compare
August 25, 2026 01:30
Copy link
Copy Markdown
Author
Sorry, something went wrong.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Reviewers
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
What's Changed
AbstractCompressionCodec.compress() wrote a length prefix of 0 for empty buffers. The Arrow IPC compression format only defines a positive length (compressed) or -1 / NO_COMPRESSION_LENGTH (stored uncompressed); a 0 prefix is undefined. As a result, C++/PyArrow reject Java-produced streams that contain empty buffers, even though Java itself accepts them on read.
This changes the empty-buffer shortcut in compress() to write CompressionUtil.NO_COMPRESSION_LENGTH (-1) instead of 0.
decompress() is intentionally left unchanged:
Added a parameterized test (testEmptyBufferWritesUncompressedSentinel, covering LZ4 and ZSTD) that compresses an empty buffer, asserts the prefix equals NO_COMPRESSION_LENGTH, and asserts it round-trips back to a zero-length buffer. The pre-existing testEmptyBuffer continues to pass with empty buffers now routed through the -1 path.
Closes #1196.