Deprecate windowslinetermination CSV option

[utkarshparekh]

Description

Deprecates the unused libcudf windowslinetermination CSV reader option. The option is stored in csv_reader_options but is not used by the CSV reader.

This change:

• Marks the getter, setter, and builder APIs as deprecated in 26.10, with removal planned for 26.12 or later.
• Directs callers to rely on the default lineterminator='\n', which supports CRLF input.
• Removes the deprecated option from the CSV reader benchmark.
• Adds a regression test confirming that CRLF input, including blank lines, is read correctly using the default options.
• Leaves the Cython declarations in place until the deprecated C++ APIs are removed.

No Python-facing deprecation warning is needed because this option is not exposed through the Python API.

Closes #15985.

Testing

• Added CsvReaderTest.WindowsLineTerminators.
• All applicable pre-commit hooks passed.
• Pinned clang-format check passed.
• Doxygen 1.9.1 check passed.
• The C++ test was not executed locally because the development machine does not have an NVIDIA GPU.

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[copy-pr-bot]

This pull request requires additional validation before any workflows can run on NVIDIA's runners.

Pull request vetters can view their responsibilities here.

Contributors can view more details about this message here.

[coderabbitai]

Note

Reviews paused

It looks like this branch is under active development. To avoid overwhelming you with review comments due to an influx of new commits, CodeRabbit has automatically paused this review. You can configure this behavior by changing the reviews.auto_review.auto_pause_after_reviewed_commits setting.

Use the following commands to manage reviews:

• @coderabbitai resume to resume automatic reviews.
• @coderabbitai review to trigger a single review.

Use the checkboxes below for quick actions:

• ▶️ Resume reviews
• 🔍 Trigger review

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 11a33d4a-8445-49bf-aafa-8403b56e35ca

📥 Commits

Reviewing files that changed from the base of the PR and between 3a1cebe and bef5971.

📒 Files selected for processing (3)

• cpp/benchmarks/io/csv/csv_reader_options.cpp
• cpp/include/cudf/io/csv.hpp
• cpp/tests/io/csv_test.cpp

🚧 Files skipped from review as they are similar to previous changes (3)

• cpp/tests/io/csv_test.cpp
• cpp/benchmarks/io/csv/csv_reader_options.cpp
• cpp/include/cudf/io/csv.hpp

Included review availability: Your plan provides up to 8 included reviews per hour; 7 remain after this review.

---

📝 Walkthrough

Summary by CodeRabbit

• Deprecations

  • Deprecated CSV reader options for explicitly enabling Windows-style line termination handling.
  • CSV parsing continues to support Windows CRLF line endings without requiring these options.

• Bug Fixes

  • Verified correct parsing of CRLF-delimited CSV data.
  • Added coverage confirming numeric and text values are read correctly from Windows-style line endings.
  • Simplified CSV configuration while preserving existing Windows line-ending support.

Walkthrough

The CSV reader deprecates Windows line termination APIs, adds CRLF parsing coverage, and removes the deprecated option from the benchmark configuration.

Changes

CSV line termination handling

Layer / File(s)	Summary
Deprecate APIs and validate CRLF parsing cpp/include/cudf/io/csv.hpp, cpp/tests/io/csv_test.cpp	CSV reader Windows line termination methods are marked deprecated. A test validates CRLF parsing with integer and string columns.
Remove deprecated benchmark configuration cpp/benchmarks/io/csv/csv_reader_options.cpp	The benchmark no longer enables Windows line termination and updates the SPDX copyright notice.

Estimated code review effort: 2 (Simple) | ~10 minutes

Merge Risk: ⚪ Minimal · up to bef59

This change deprecates an unused CSV option while preserving the default CRLF-compatible behavior and adding regression coverage; no actionable merge-blocking risk remains after normal checks and review.

Suggested reviewers: ttnghia

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 42.86% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 7 functions across 3 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the primary change: deprecating the CSV windowslinetermination option.
Description check	✅ Passed	The description accurately explains the deprecation, benchmark update, regression test, compatibility behavior, and API impact.
Linked Issues check	✅ Passed	The changes satisfy issue #15985 by deprecating the unused getter, setter, and builder APIs and validating CRLF input behavior.
Out of Scope Changes check	✅ Passed	The code changes remain within scope, with only related benchmark, API, test, and copyright updates included.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}

[utkarshparekh]

@coderabbitai help

[coderabbitai]

Chat

There are 3 ways to chat with CodeRabbit:

• Review comments: Directly reply to a review comment made by CodeRabbit. Example:
  • I pushed a fix in commit <commit_id>, please review it.
  • Open a follow-up GitHub issue for this discussion.
• Files and specific lines of code (under the "Files changed" tab): Tag @coderabbitai in a new review comment at the desired location with your query.
• PR comments: Tag @coderabbitai in a new PR comment to ask questions about the PR branch. For the best results, please provide a very specific query, as very limited context is provided in this mode. Examples:
  • @coderabbitai gather interesting stats about this repository and render them as a table. Additionally, render a pie chart showing the language distribution in the codebase.
  • @coderabbitai read the files in the src/scheduler package and generate a class diagram using mermaid and a README in the markdown format.

CodeRabbit commands

These commands are invoked using PR/Issue comments.

• @coderabbitai pause to pause the reviews on a PR.
• @coderabbitai resume to resume the paused reviews.
• @coderabbitai review to trigger an incremental review. This is useful when automatic reviews are disabled for the repository.
• @coderabbitai full review to do a full review from scratch and review all the files again.
• @coderabbitai rate limit to show your current review rate limit status.
• @coderabbitai summary to regenerate the summary of the PR.
• @coderabbitai evaluate custom pre-merge check --instructions <custom-checks-instructions> --name <custom-checks-title> [--mode <error|warning>] to validate the custom pre-merge checks instructions. Defaults to error when --mode is omitted.
• @coderabbitai ignore pre-merge checks to override pre-merge checks and get an approval on PR.
• @coderabbitai run pre-merge checks to run pre-merge checks on the pull request.
• @coderabbitai generate docstrings to generate docstrings for this PR.
• @coderabbitai generate sequence diagram to generate a sequence diagram of the changes in this PR.
• @coderabbitai generate unit tests to generate unit tests for this PR.
• @coderabbitai emit path instructions to emit generated path-specific review instructions for this repository.
• @coderabbitai resolve merge conflict to automatically resolve merge conflicts.
• @coderabbitai autofix to automatically fix issues identified in unresolved review comments.
• @coderabbitai fix-ci to automatically fix failing CI checks by creating a stacked PR with fixes.
• @coderabbitai resolve to resolve all the CodeRabbit review comments.
• @coderabbitai configuration to show the current CodeRabbit configuration for the repository.
• @coderabbitai generate configuration to create a PR that adds the current resolved configuration as .coderabbit.yaml (or show it if already present).
• @coderabbitai help to get help.

Other keywords and placeholders

• Add @coderabbitai ignore or @coderabbit ignore anywhere in the PR description to prevent this PR from being reviewed.
• Add @coderabbitai summary to generate the high-level summary at a specific location in the PR description.
• Add @coderabbitai anywhere in the PR title to generate the title automatically.

Status, support, documentation and community

• Visit our status page to check the current availability of CodeRabbit.
• Create a ticket on our support page for assistance with any issues or questions.
• Visit our documentation site for detailed information on how to use CodeRabbit.
• Join our Discord community to connect with other users and get help from the community.
• Follow us on X/Twitter for updates and announcements.

[utkarshparekh]

Could a maintainer please add the improvement and non-breaking labels? This PR introduces a non-breaking API deprecation, and Label Checker is currently failing.

[utkarshparekh]

I pushed a fix in commit ecf0463, please review it.

[utkarshparekh]

@coderabbitai I pushed a fix in commit 1f54e05, please review it.

[coderabbitai]

@utkarshparekh, I’ll review the latest changes in commit 1f54e05.

✅ Action performed

Review finished.

Note: CodeRabbit is an incremental review system and does not re-review already reviewed commits. This command is applicable only when automatic reviews are paused.

[utkarshparekh]

@coderabbitai I pushed a fix in commit f532729, please review it

[coderabbitai]

@utkarshparekh I’ll review the latest changes in commit f532729.

✅ Action performed

Review finished.

Note: CodeRabbit is an incremental review system and does not re-review already reviewed commits. This command is applicable only when automatic reviews are paused.

[vyasr]

Thank you!

[vyasr]

/ok to test 3f55fe0

[coderabbitai]

Note

GitHub couldn't provide a complete incremental comparison for this pull request, so CodeRabbit is performing a full review instead. This review may take a little longer.

[bdice]

/ok to test 09473b4

[bdice]

I triggered CI again. Please don't merge the upstream branch again if CI passes. :)

[vyasr]

/ok to test 572ab2d

[coderabbitai]

Note

GitHub couldn't provide a complete incremental comparison for this pull request, so CodeRabbit is performing a full review instead. This review may take a little longer.

[vyasr]

/ok to test e090d1f

[vuule]

/ok to test bef5971

[coderabbitai]

Note

GitHub couldn't provide a complete incremental comparison for this pull request, so CodeRabbit is performing a full review instead. This review may take a little longer.

[vuule]

@utkarshparekh, the new test is failing in CI

[utkarshparekh]

@utkarshparekh, the new test is failing in CI

The new CRLF test parsed the values correctly, but it used CUDF_TEST_EXPECT_TABLES_EQUAL, which also requires identical nullability. The CSV reader output is nullable with zero nulls, while the expected wrappers are non-nullable. I’ve updated the new test to use CUDF_TEST_EXPECT_TABLES_EQUIVALENT, so it verifies the intended values and types without requiring identical null-mask representation. Could you please approve the new commit for CI?

[vuule]

/ok to test f9e78b5

[utkarshparekh]

The new CRLF test now passes across the full conda-cpp-tests matrix. The remaining spark-rapids-jni failure is the known downstream RMM compatibility issue tracked in NVIDIA/cudf-spark-jni#5041, with a fix in NVIDIA/cudf-spark-jni#5042. No additional CSV-related change appears necessary in this PR.

[utkarshparekh]

The remaining pre-commit.ci failure is unrelated to this PR’s CSV changes. It comes from python/cudf/cudf/core/udf/rolling_utils.py, introduced on main by #23598, and reports numpydoc errors GL08 and RT01. The CSV-related hooks and C++ test matrix pass. I have not modified the unrelated Python file in this PR.