GH-34577 [Python] Expose eol and null_string csv WriteOptions

[MartinNowak]

Rationale for this change

Expose remaining csv write options to pyarrow.

What changes are included in this PR?

Adding eol and null_string to csv.WriteOptions.

Are these changes tested?

Yes, testing of setters included.

Are there any user-facing changes?

• GitHub Issue: [R][Python] Expand coverage of and align R/Python to C++ CSV WriteOptions #34577

[github-actions]

⚠️ GitHub issue #34577 has been automatically assigned in GitHub to PR creator.

[AlenkaF]

Thank you for submitting a PR!
There are some fixes needed for the CI to pass:

• Linter error:
  python/pyarrow/tests/test_csv.py:363:89: E501 line too long (119 > 88 characters)
• Python builds error:
  pyarrow/_csv.pyx:1431:34: Object of type 'CCSVWriteOptions &' has no attribute 'eol'
  -> CCSVWriteOptions will need to be updated in the libarrow.pxd

[AlenkaF]

The failures are connected, see:

______________________________ test_write_options ______________________________

    def test_write_options():
        cls = WriteOptions
        opts = cls()
    
>       check_options_class(
            cls, include_header=[True, False], delimiter=[',', '\t', '|'],
            eol=['\n', '\r\n'], null_string=['', 'NA'],
            quoting_style=['needed', 'none', 'all_valid'])

opt/conda/envs/arrow/lib/python3.9/site-packages/pyarrow/tests/test_csv.py:362: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
opt/conda/envs/arrow/lib/python3.9/site-packages/pyarrow/tests/test_csv.py:111: in check_options_class
    opts = cls(**non_defaults)
pyarrow/_csv.pyx:1388: in pyarrow._csv.WriteOptions.__init__
    ???
pyarrow/_csv.pyx:1446: in pyarrow._csv.WriteOptions.null_string.__set__
    ???
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

>   ???
E   TypeError: expected bytes, NoneType found

[MartinNowak]

Was on vacation and it took a bit longer to get back to this. Hope it runs through now 🤞 @AlenkaF.

[MartinNowak]

???
E TypeError: expected bytes, NoneType found

It found this glorious typo 🤦. Only have semi-working syntax highlighting and didn't have enough time to figure out how to run the tests locally :/.

[AlenkaF]

The tests are passing 👍
But the docstrings need an update:

pyarrow._csv.WriteOptions
-> pyarrow._csv.WriteOptions(include_header=None, *, batch_size=None, delimiter=None, eol=None, null_string=None, quoting_style=None)
PR01: Parameters {'delimiter', 'null_string', 'eol', 'batch_size', 'quoting_style'} not documented
PR04: Parameter "")" has no type

[MartinNowak]

The tests are passing 👍
But the docstrings need an update:

Needed to escape the backslash to render in final doc rather than to break the doc comment.

[MartinNowak]

The macOS failures seem to be apache/orc#2357 and were not present previously f95d305 @AlenkaF.

[raulcd]

The macOS failures are fixed on main, can you rebase so they are fixed on CI, please?

[raulcd]

@github-actions crossbow submit -g python

[github-actions]

Revision: 08fa4412afc3bbb2e1599a4ad9557fe8a0f3a075

Submitted crossbow builds: ursacomputing/crossbow @ actions-c05e9be928

Task	Status
example-python-minimal-build-fedora-conda
example-python-minimal-build-ubuntu-venv
test-conda-python-3.10
test-conda-python-3.10-hdfs-2.9.2
test-conda-python-3.10-hdfs-3.2.1
test-conda-python-3.10-pandas-latest-numpy-latest
test-conda-python-3.11
test-conda-python-3.11-dask-latest
test-conda-python-3.11-dask-upstream_devel
test-conda-python-3.11-hypothesis
test-conda-python-3.11-pandas-latest-numpy-1.26
test-conda-python-3.11-pandas-latest-numpy-latest
test-conda-python-3.11-pandas-nightly-numpy-nightly
test-conda-python-3.11-pandas-upstream_devel-numpy-nightly
test-conda-python-3.11-spark-master
test-conda-python-3.12
test-conda-python-3.12-cpython-debug
test-conda-python-3.13
test-conda-python-3.9
test-conda-python-3.9-pandas-1.1.3-numpy-1.19.5
test-conda-python-emscripten
test-cuda-python-ubuntu-22.04-cuda-11.7.1
test-debian-12-python-3-amd64
test-debian-12-python-3-i386
test-fedora-42-python-3
test-ubuntu-22.04-python-3
test-ubuntu-22.04-python-313-freethreading
test-ubuntu-24.04-python-3

[raulcd]

Thanks for the PR, sorry I took a little to review.
This seems to only be testing that the options class can be generated but is not indeed testing the options, on test_csv.py we have other tests that indeed test the options like:

arrow/python/pyarrow/tests/test_csv.py

Line 1929 in 697f501

def test_write_read_round_trip():

or

arrow/python/pyarrow/tests/test_csv.py

Line 1973 in 697f501

def test_write_quoting_style():

Can we test the options are indeed working as expected when writing the CSV?