[Data] Improve read_text trailing newline semantics#53860
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bveeramani merged 2 commits intomasterfrom Jun 16, 2025
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Signed-off-by: Balaji Veeramani <bveeramani@berkeley.edu>
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Pull Request Overview
This PR updates read_text to use Python’s splitlines() for newline splitting and adjusts tests to match the new empty‐line behavior, plus simplifies the partitioned‐filter test.
- Switched from
.split("\n")to.splitlines()in_read_streamto improve newline handling. - Updated expectations in
test_text.pyfor empty‐line counts and removed counter logic in partitioned‐filter tests. - Added
pytest.mark.parametrizeonPartitionStylefor the partitioned‐read test.
Reviewed Changes
Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| python/ray/data/_internal/datasource/text_datasource.py | Use splitlines() instead of split("\n") in _read_stream. |
| python/ray/data/tests/test_text.py | Adjusted empty‐line count assertions, removed counter-based checks, and parameterized the partition style. |
Comments suppressed due to low confidence (2)
python/ray/data/tests/test_text.py:68
- Add a test case for reading files that end with a trailing newline under
drop_empty_lines=Falseto verify howsplitlines()handles the final empty line, ensuring the behavior is as intended.
assert ds.count() == 4
python/ray/data/_internal/datasource/text_datasource.py:31
- Update the docstring for
_read_streamto note that it now usessplitlines()and does not preserve trailing empty lines, clarifying the behavior change whendrop_empty_lines=False.
def _read_stream(self, f: "pyarrow.NativeFile", path: str) -> Iterator[Block]:
| builder = DelegatingBlockBuilder() | ||
|
|
||
| lines = data.decode(self.encoding).split("\n") | ||
| lines = data.decode(self.encoding).splitlines() |
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Using splitlines() here will omit trailing empty lines (e.g., from files ending with a newline), which changes the semantics of drop_empty_lines=False compared to split('\n'). Consider explicitly preserving trailing empty lines if you intend to match the previous behavior, or document this change clearly.
Suggested change
| lines = data.decode(self.encoding).splitlines() | |
| lines = data.decode(self.encoding).split('\n') |
read_text newline handlingread_text trailing newline semantics
raulchen
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Jun 16, 2025
elliot-barn
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<!-- Thank you for your contribution! Please review https://github.com/ray-project/ray/blob/master/CONTRIBUTING.rst before opening a pull request. --> <!-- Please add a reviewer to the assignee section when you create a PR. If you don't have the access to it, we will shortly find a reviewer and assign them to your PR. --> ## Why are these changes needed? <!-- Please give a short summary of the change and the problem this solves. --> `read_text` currently treats a trailing newline as an empty line, which can lead to unexpected results. This isn’t consistent with how standard Python methods like `str.splitlines()` behave. Since trailing newlines are common in text files, this PR updates the behavior to ignore them. ## Related issue number <!-- For example: "Closes #1234" --> ## Checks - [ ] I've signed off every commit(by using the -s flag, i.e., `git commit -s`) in this PR. - [ ] I've run `scripts/format.sh` to lint the changes in this PR. - [ ] I've included any doc changes needed for https://docs.ray.io/en/master/. - [ ] I've added any new APIs to the API Reference. For example, if I added a method in Tune, I've added it in `doc/source/tune/api/` under the corresponding `.rst` file. - [ ] I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/ - Testing Strategy - [ ] Unit tests - [ ] Release tests - [ ] This PR is not tested :( --------- Signed-off-by: Balaji Veeramani <bveeramani@berkeley.edu> Signed-off-by: elliot-barn <elliot.barnwell@anyscale.com>
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) <!-- Thank you for your contribution! Please review https://github.com/ray-project/ray/blob/master/CONTRIBUTING.rst before opening a pull request. --> <!-- Please add a reviewer to the assignee section when you create a PR. If you don't have the access to it, we will shortly find a reviewer and assign them to your PR. --> ## Why are these changes needed? <!-- Please give a short summary of the change and the problem this solves. --> `read_text` currently treats a trailing newline as an empty line, which can lead to unexpected results. This isn’t consistent with how standard Python methods like `str.splitlines()` behave. Since trailing newlines are common in text files, this PR updates the behavior to ignore them. ## Related issue number <!-- For example: "Closes ray-project#1234" --> ## Checks - [ ] I've signed off every commit(by using the -s flag, i.e., `git commit -s`) in this PR. - [ ] I've run `scripts/format.sh` to lint the changes in this PR. - [ ] I've included any doc changes needed for https://docs.ray.io/en/master/. - [ ] I've added any new APIs to the API Reference. For example, if I added a method in Tune, I've added it in `doc/source/tune/api/` under the corresponding `.rst` file. - [ ] I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/ - Testing Strategy - [ ] Unit tests - [ ] Release tests - [ ] This PR is not tested :( --------- Signed-off-by: Balaji Veeramani <bveeramani@berkeley.edu>
elliot-barn
pushed a commit
that referenced
this pull request
Jul 2, 2025
<!-- Thank you for your contribution! Please review https://github.com/ray-project/ray/blob/master/CONTRIBUTING.rst before opening a pull request. --> <!-- Please add a reviewer to the assignee section when you create a PR. If you don't have the access to it, we will shortly find a reviewer and assign them to your PR. --> ## Why are these changes needed? <!-- Please give a short summary of the change and the problem this solves. --> `read_text` currently treats a trailing newline as an empty line, which can lead to unexpected results. This isn’t consistent with how standard Python methods like `str.splitlines()` behave. Since trailing newlines are common in text files, this PR updates the behavior to ignore them. ## Related issue number <!-- For example: "Closes #1234" --> ## Checks - [ ] I've signed off every commit(by using the -s flag, i.e., `git commit -s`) in this PR. - [ ] I've run `scripts/format.sh` to lint the changes in this PR. - [ ] I've included any doc changes needed for https://docs.ray.io/en/master/. - [ ] I've added any new APIs to the API Reference. For example, if I added a method in Tune, I've added it in `doc/source/tune/api/` under the corresponding `.rst` file. - [ ] I've made sure the tests are passing. Note that there might be a few flaky tests, see the recent failures at https://flakey-tests.ray.io/ - Testing Strategy - [ ] Unit tests - [ ] Release tests - [ ] This PR is not tested :( --------- Signed-off-by: Balaji Veeramani <bveeramani@berkeley.edu> Signed-off-by: elliot-barn <elliot.barnwell@anyscale.com>
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Why are these changes needed?
read_textcurrently treats a trailing newline as an empty line, which can lead to unexpected results. This isn’t consistent with how standard Python methods likestr.splitlines()behave. Since trailing newlines are common in text files, this PR updates the behavior to ignore them.Related issue number
Checks
git commit -s) in this PR.scripts/format.shto lint the changes in this PR.method in Tune, I've added it in
doc/source/tune/api/under thecorresponding
.rstfile.