py-1.39.0

## 🚀 Performance improvements

- Lower `arg_{min,max}` to streaming engine (#26845)
- Additional IR slice pushdown after filter pushdown (#26815)
- Streaming first/last on Enum through physical (#26783)
- Fast filter for scalar predicates (#26745)
- Allow SimpleProjection in streaming engine to rename (#26709)
- Streaming cloud download for `scan_csv` (#26637)
- Drop columns only needed for predicates after the predicate is applied (#26703)
- Run projection pushdown after predicate pushdown (#26688)
- Comparison literal downcasting (#26663)
- Add dynamic predicates for TopK (#26495)
- Increase minimum default parquet row group prefetch to 8 (#26632)
- Partial predicate conversion to PyArrow (#26567)
- Streaming cloud download for `scan_ndjson` / `scan_lines` (#26563)
- Grab GIL fewer times during Object join materialization (#26587)
- Improve CSV and NDJSON cloud sink performance (#26545)
- Tune cloud writer performance (#26518)
- Allow parallel InMemorySinks in streaming engine (#26501)
- Add streaming `AsOf` join node (#26398)
- Don't always rechunk on gather of nested types (#26478)

## ✨ Enhancements

- Support Expr for holidays in business day calculations (#26193)
- Parameter for pivot to always include value column name (#26730)
- Raise error in `.collect_schema()` when `arr.get()` is out-of-bounds (#26866)
- Extend `Expr.reinterpret` to all numeric types of the same size (#26401)
- Add missing\_columns parameter to scan\_csv (#26787)
- Clear no-op scan projections (#26858)
- Support nested datatypes for `{min,max}_by` (#26849)
- Support SQL `ARRAY` init from typed literals (#26622)
- Accept table identifier string in `scan_iceberg()` (#26826)
- Add a convenience `make fresh` command to the Makefile (#26809)
- Expose "use\_zip64" Workbook option for `write_excel` (#26699)
- Add unstable `LazyFrame.sink_iceberg` (#26799)
- Add maintain order argument on implode (#26782)
- Speed up casting primitive to bool by at least 2x (#26823)
- Support ASCII format table input to `pl.from_repr` (#26806)
- Enable rowgroup skipping for float columns (#26805)
- Add expression context to errors (#26716)
- Add Decimal support for product reduction (#26725)
- Support all Iceberg V2 arrow types in sink\_parquet arrow\_schema parameter (#26669)
- Re-work behavior of arrow\_schema parameter on sink\_parquet (#26621)
- Add `contains_dtype()` method for `Schema` (#26661)
- Implement `truncate` as a "to\_zero" rounding mode (#26677)
- More generic streaming GroupBy lowering (#26696)
- Create an `Alignment` TypeAlias (#26668)
- Add basic MemoryManager to track buffered dataframes for out-of-core support later (#26443)
- Add `truncate` Expression for numeric values (#26666)
- Better error messages for hex literal conversion issues in the SQL interface (#26657)
- Add SQL support for `LPAD` and `RPAD` string functions (#26631)
- Support SQL "FROM-first" `SELECT` query syntax (#26598)
- Improve `base_type` typing (#26602)
- Bump Chrono to 0.4.24, enabling stricter parsing of `%.3f`/`%.6f`/`%.9f` specifiers (#26075)
- Expose unstable `assert_schema_equal` in py-polars (#24869)
- Allow parsing of compact ISO 8601 strings (#24629)
- Add optional "label" param to DataFrame `corr` (#26588)
- Streaming cloud download for `scan_ndjson` / `scan_lines` (#26563)
- Configuration to cast integers to floats in `cast_options` for `scan_parquet` (#26492)
- Add escaping to quotes and newlines when reading JSON object into string (#26578)
- Standardise on RFC-5545 when doing datetime arithmetic on timezone-aware datetimes (#26425)
- Support `sas_token` in Azure credential provider (#26565)
- Relax SQL requirement for derived tables and subqueries to have aliases (#26543)
- Add polars-config and pl.Config.reload\_env\_vars() (#26524)
- Record path for object store error raised from sinks (#26541)
- Use CRC64NVME for checksum in aws sinks (#26522)
- Add `get()` for binary Series (#26514)
- Add streaming `AsOf` join node (#26398)
- Add primitive filter -> agg lowering in streaming GroupBy (#26459)
- Support for the SQL `FETCH` clause (#26449)

## 🐞 Bug fixes

- Prevent `Boolean` arithmetic with integer literals producing `Unknown` type in streaming engine (#26878)
- Fix sink to partitioned S3 from Windows corrupted slashes (#26889)
- Remove outdated warning about List columns in unique() (#26295) (#26890)
- Restore pyarrow predicate conversion for is\_in (#26811)
- Release GIL before df.to\_ndarray() to avoid deadlock (#26832)
- Fix panic on CSV count\_rows with FORCE\_ASYNC (#26883)
- Add scalar comparisons for `UInt128` series (#26886)
- Fix shape error not raised for 0 width inputs with non-0 height for streaming horizontal concat (#26877)
- Fix streaming zip-broadcast node did not raise shape mismatch on empty recv from ready port (#26871)
- Fix incorrect output list.eval with scalar expr, fix panic on list.agg with nulls (#26868)
- Allow list argument in `group_by().map_groups()` (#26707)
- Support for ADBC drivers instantiated with `dbc` in `DataFrame.write_database` (#26157)
- Incorrect arg\_sort with descending+limit (#26839)
- Raise error in `.collect_schema()` when `arr.get()` is out-of-bounds (#26866)
- Return ComputeError instead of panicking in map\_groups UDF (#26665)
- Issue PerformanceWarning in `LazyFrame.__contains__` (#26734)
- Correct type hint for `map_columns` function parameter (#26487)
- Apply thousands\_separator to count/null\_count in describe() for non-numeric columns (#26486)
- Ensure proper handling of `timedelta` when multiplying with a `Series` (#26830)
- Correct type hint for `function` parameter in `DataFrame.map_columns` (#26372)
- Segfault in `JoinExec` on deep plan (#26796)
- Fix unary expressions on literal in `over` context (#26827)
- Fix `{min,max}_by` in streaming engine for Boolean full `{min,max}` value column (#26848)
- Fix debug panic on clip with nan bound (#26854)
- Support grouped `{arg_,}_{min,max}` for Categoricals (#26856)
- Throw an error if a string is passed to LazyFrame.pivot `on_columns` (#26852)
- Preserve input float precision in `rolling_cov()` and `rolling_corr()` with mixed input types (#26820)
- Preserve row count when converting zero-column DataFrame via arrow PyCapsule interface (#26835)
- Prevent infinite recursion in streaming `group_by` fallback (#26801)
- Use `RowEncodingContext::Struct` when determining `D::Struct` encoded item len (#26817)
- Incorrectly applied CSE on different map\_batches functions (#26822)
- Fix duplicated query execution on todo panic when combining `collect(engine='streaming')` with `POLARS_AUTO_NEW_STREAMING` (#26792)
- Prevent predicate pushdown across Sort with baked-in slice (#26804)
- Restore compatibility with `pd.Timedelta` (#26785)
- Fix panic on lazy sink\_parquet created in pipe\_with\_schema (#26784)
- Support `{column_name}` and `{index}` placeholders in pl.format string (#26771)
- Do not use merge-join if `nulls_last` is unknown (#26778)
- Normalize float zeros in Parquet column statistics (#26776)
- Fix out-of-bounds for positive offset in windowed `rolling` (#26724)
- Raise error when `.get()` is out-of-bounds in group by context (#26752)
- Boolean `bitwise_xor` aggregation inverted when column contains nulls (#26749)
- Parameter nulls\_last was ignored in over (#26718)
- Allow missing time in inexact strptime (#26714)
- Respect `nulls_last` in `sort_by` within `group_by().agg()` slow path (#26681)
- Return `NaN` when using `corr()` with a literal and expr (#26697)
- Allow strict horizontal concat with empty df (#26345)
- Fix `PoisonError` panic caused by reentrant usage of file cache (#26627)
- Return null for int values exceeding 128-bit range with `strict=False` (#26674)
- Incorrect boolean min/max with nulls (#26671)
- Slice-slice pushdown for n\_rows (#26673)
- Resolve panic in `Enum` struct slicing (#26643)
- Fix CSPE for group\_by.map\_groups (#26640)
- Remove non-existent parameter from `SQLContext` typing overloads (#26658)
- Address `pl.from_epoch` losing fractional seconds (#26419)
- Fix `to_pandas()` on empty enum Series did not preserve enum dictionary (#26610)
- Rounding behaviour for `f32` values with "HalfAwayFromZero" mode (#26624)
- Updated Sum Type Hint (#26629)
- Don't allow namespace registration to override standard methods or properties (#26450)
- Correct arg\_(min|max) for scalar columns (#26609)
- Use monkeypatch.chdir in test\_sink\_path\_slicing\_utf8\_boundaries\_26324 (#26616)
- Respect SQL semantics for cumulative functions mapped via `OVER` clause (#26570)
- Fix incorrect multiplexer output ordering on source token stop request (#26561)
- Fix PyIceberg filter on boolean column (#26550)
- Set `dictionary_page_offset` when dictionary encoding is used and point `data_page_offset` to the first data page (#26542)
- Move query parameters to request body when retrieving Unity Catalog temporary credentials (#26539)
- Ensure `read_csv_batched()` prints deprecation warning (#26530)
- Implement `PhysicalExpr` for `MinBy`/`MaxBy` nodes (#26506)
- Refactor row-encoding logic in IR join lowering into separate function (#26512)
- Correctly check for path extensions (#26513)
- Change AsOf join to be based on `TotalOrd` (#26497)
- Correctly raise error on failing nested strict casts (#26499)
- Prevent invalid type casts in `replace_strict()` (#26453)
- Return `null` when dividing literals by `0` (#26343)
- Fix type-hint for Series.quantile (#26422)

## 📖 Documentation

- Mention ComputeContexts create ephemeral environments by default and hint at re-use (#26692)
- Remove confusing join validation note (#26795)
- Fix formatting in categorical documentation (#26746)
- Fix broken AI policy link (#26728)
- Create Polars Cloud Glossary (#26690)
- Additional SQL documentation (#26662)
- Include invalidate\_caches in bisect instructions (#26641)
- Add git bisect guide to contributing docs (#26634)
- Fix Polars Cloud examples (formatting \& type hints) (#26625)
- Updated Airflow orchestration documentation (#26585)
- Improve  SQL docs for `EXTRACT` and `DATE_PART` functions (#26575)
- Fix docstring for bitwise\_count\_zeros method (#26519)
- Add `get()` for binary Series (#26514)

## 🛠️ Other improvements

- Use large linux-arm runner for release (#26898)
- Ensure `.gitignore` and `.typos.toml` exclude `"_polars_runtime*"` directories (#26842)
- Additional IR slice pushdown after filter pushdown (#26815)
- Add private `_expand_paths` scan function (#26798)
- Change `Expr` sortedness container to `AExprSorted` and add `nulls_last` to `PyExpr.set_sorted()` (#26781)
- Move `stop_and_buffer_pipe_contents` into `joins/utils.rs` (#26810)
- Replace iejoin `is_supported_type` macro with a closure in `predicate_pushdown/join.rs` (#26812)
- Fix first-time contributor auto-label (#26794)
- Automatically add first-contribution label (#26780)
- Add tests for functions that operate on `pl.all()` expansion (#26773)
- Make contributing policy more strict (#26772)
- Add unused argument warning to ruff rules (#26720)
- Move shared streaming CSV/NDJSON code into shared mod (#26742)
- Undo pub removal of to\_dyn\_object\_store (#26722)
- Mark `{read, scan}_ndjson` cache argument(s) as deprecated (#26711)
- Add test for predicate before join (#26705)
- Remove PlanCallback from sql (#26686)
- Bump Rust nightly compiler version (#26379)
- Remove unused problematic ArrayFromIter (#26639)
- Move more boolean code to polars\_compute, reusing kernels (#26636)
- Avoid implicit import from `importlib` (#26603)
- Cleanup `assert_schema_equal` (#26596)
- Replace some env var reading by polars-config (#26607)
- Use monkeypatch.chdir in test\_sink\_path\_slicing\_utf8\_boundaries\_26324 (#26616)
- Add `__init__.py` files and docstrings to testing directories (#26408)
- Add wrapper for clippy so it continues on warnings (#26527)
- Use `LazyFrame.clear` to clear sql (#26562)
- Update docs (#26560)
- Add backtrace coloring (#26544)
- Evaluate sql `process_except_intersect` during IR (#26516)
- Reformat LICENSE (#26532)
- Add a pipeline in which we test with `POLARS_IDEAL_MORSEL_SIZE=4` (#26420)
- Remove `test_file` and have tests create `test.parquet` in `tmp_path` (#26525)
- Refactor row-encoding logic in IR join lowering into separate function (#26512)
- Fix mypy pyiceberg expression errors (#26523)
- Make nix flake mostly work (#26517)
- Switch to custom cloud writer with IO sink metrics (#26494)
- Update `s3fs` dev dependency (#26509)
- Remove Default on DataType (#26511)
- Have parameterized series `rechunk()` if `not allow_chunks` (#26504)
- Remove dead code (`RevMapping`) (#26508)
- Upgraded `ruff`, `mypy`, `typos` (#26476)
- More SQL to IR conversion `execute_isolated` (#26455)

Thank you to all our contributors for making this release possible!
@BJohnBraddock, @EndPositive, @Jesse-Bakker, @Kevin-Patyk, @MarcoGorelli, @Matt711, @NathanHu725, @RenzoMXD, @TNieuwdorp, @Voultapher, @WaffleLapkin, @abishop1990, @alexander-beedie, @azimafroozeh, @boris324, @cBournhonesque, @carnarez, @coastalwhite, @daizutabi, @dependabot[bot], @dsprenkels, @erandagan, @etiennebacher, @gautamvarmadatla, @henryharbeck, @hutch3232, @itamarst, @jberg5, @johalnes, @kdn36, @leudz, @lukas-reining, @moktamd, @mqqz, @mroeschke, @nameexhaustion, @orlp, @pragun-ananda, @qxzcode, @ritchie46, @spock-yh, @stakeswky, @tlauli, @toroleapinc, @veeceey and [dependabot[bot]](https://github.com/apps/dependabot)