Rust Polars 0.51.0

💥 Breaking changes

• Remove, deprecate or change eager Exprs to be lazy compatible (#24027)

🚀 Performance improvements

• Use specialized decoding for all predicates for Parquet dictionary encoding (#24403)
• Allocate only for read items when reading Parquet with predicate (#24401)
• Don't aggregate groups for strict cast if original len (#24381)
• Allocate only for read items when reading Parquet with predicate (#24324)
• Native streaming int_range with len or count (#24280)
• Lower arg_unique natively to the streaming engine (#24279)
• Move unordering optimization to end (#24286)
• Do ordering simplification step after common sub-plan elimination (#24269)
• Always simplify order requirements in IR (#24192)
• Basic de-duplication of filter expressions (#24220)
• Cache the IR in pipe_with_schema (#24213)
• Lower arg_where natively to streaming engine (#24088)
• Lower Expr.shift to streaming engine (#24106)
• Lower order-preserving groupby to streaming engine (#24053)
• Lower .sort(maintain_order=True).head() to streaming top_k (#24014)
• Lower top-k to streaming engine (#23979)
• Allow order pass through Filters and relax to row-seperable instead of elementwise (#23969)

✨ Enhancements

• Roundtrip BinaryOffset type through Parquet (#24344)
• Add opt-in unstable functionality to load interval types as Struct (#24320)
• Add user guide section on AWS role assumption (#24421)
• Support unique / n_unique / arg_unique for array columns (#24406)
• Support S3 virtual-hosted–style URI (#24405)
• Remove explicit file create for local async writes (#24358)
• Support Partitioning sinks in cloud (#24399)
• User-friendly error message on empty path expansion (#24337)
• Add Polars security policy (#24314)
• Allow pl.Expr.log to take in an expression (#24226)
• Implement diff() in streaming engine (#24189)
• Enable Expr.diff(n) for negative n (#24200)
• Allow upcasting null-typed columns to nested column types in scans (#24185)
• Log pyarrow predicate conversion result in sensitive verbose logs (#24186)
• Add a deprecation warning for pl.Series.shift(Null) (#24114)
• Improve Debug formatting of DataType (#24056)
• Add cum_* as native streaming nodes (#23977)
• Add peak_{min,max} support for booleans (#24068)
• Add DataFrame.map_columns for eager evaluation (#23821)
• Add native streaming for peaks_{min,max} (#24039)
• IR graph arrows, monospace font, box nodes (#24021)
• Add DataTypeExpr.default_value (#23973)
• Lower rle to a native streaming engine node (#23929)
• Add support for Int128 to pyo3-polars (#23959)
• Lower rle_id to a native streaming node (#23894)
• Pass endpoint_url loaded from CredentialProviderAWS to scan/write_delta (#23812)
• Dispatch scan_iceberg to native by default (#23912)
• Lower unique_counts and value_counts to streaming engine (#23890)
• Implement dt.days_in_month function (#23119)
• Fix errors on native scan_iceberg (#23811)
• Reinterpret binary data to fixed size numerical array (#22840)
• Make rolling_map serializable (#23848)

🐞 Bug fixes

• Fix AggState on all_literal in BinaryExpr (#24461)
• Replace unsafe with collect (#24494)
• Show IR sort options in explain (#24465)
• Benchmark CI import (#24463)
• Fix schema on ApplyExpr with single row literal in agg context (#24422)
• Fix planner schema for dividing pl.Float32 by int (#24432)
• Fix panic scanning from AWS legacy global endpoint URL (#24450)
• Emit proper tuple for Log in expression nodes (#24426)
• Do not propagate struct of nulls with null (#24420)
• Be stricter with invalid NDJSON input when ignore_errors=False (#24404)
• Implement approx_n_unique for temporal dtypes and Null (#24417)
• Correct sink_ipc overload for compression (#24398)
• Enable all integer dtypes for by parameter in join_asof (#24384)
• Fix Group-By + filter aggregation performs subsequent operations on all data instead of only filtered data (#24373)
• Fix incorrect output ordering for row-separable exprs (#24354)
• Fix Series.__arrow_c_stream__ for Decimal and other logical types (#24120)
• Match output type to engine for Struct arithmetic (#23805)
• Make mmap use MAP_PRIVATE rather than MAP_SHARED (#24343)
• Fix cloud iceberg scan DATASET_PROVIDER_VTABLE error (#24338)
• Incorrect logic in negative streaming slice (#24326)
• Do not error on non-list Sequence for columns parameter in read_excel (#23967)
• Invalid conversion from non-bit numpy bools (#24312)
• Make dt.epoch('s') serializable (#24302)
• Make Expr.rechunk serializable (#24303)
• Schema mismatch for 'log' operation (#24300)
• Incorrect first/last aggregate in streaming engine (#24289)
• Fix group offsets in sliced groups (#24274)
• Panic in inexact date(time) conversion (#24268)
• The index_of feature should not depends on the object feature (#24256)
• Keep DSL cache after serialization and deserialization (#24265)
• Sanitize and warn about eval usage (#24262)
• Unique with keep="none" in new optimization pass (#24261)
• Correct size limits for Decimal cast (#24252)
• Unordered unions in check order observing pass (#24253)
• Fix dtype for slice on Literal in agg context (#24137)
• Fix incorrect filter(lit(True)) when scanning hive (#24237)
• In-memory group_by on 128-bit integers (#24242)
• Fix panic in gather inside groupby with invalid indices (#24182)
• Release the GIL in map_groups (#24225)
• Remove extra explode in LazyGroupBy.{head,tail} (#24221)
• Fix panic in polars cloud CSV scan (#24197)
• Fix panic when loading categorical columns from IO plugin (#24205)
• Fix engine type for concat_list on AggScalar implode (#24160)
• Rolling_mean handle centered weights with len(values) < window_size (#24158)
• Reading is_in predicate for Parquet plain strings (#24184)
• Make PyCategories pickleable (#24170)
• Remove unused unsound function to_mutable_slice (#24173)
• PyO3 extension types giving compat_level errors (#24166)
• Allow non-elementwise by in top_k (#24164)
• Fix sort_by for group_by_dynamic context (#24152)
• Input-independent length aggregations in streaming (#24153)
• Release GIL when iterating df in to_arrow (#24151)
• Respect non-elementwise join_where conditions (#24135)
• Resolve schema mismatch for div on Boolean (#24111)
• Keep name when doing empty group-aware aggregation (#24098)
• Implode instead of reshape_list (#24078)
• Rolling mean with weights incorrect when min_samples < window_size (#23485)
• Allow merge_sorted for all types (#24077)
• Include datatypes in row_encode expression (#24074)
• Include UDF materialized type in serialization (#24073)
• Correct .rolling() output type for non-aggregations (#24072)
• Correct planner output schema for join_asof (#24071)
• Allow %B to work without specifying day (#24009)
• Correct output for fold and reduce (#24069)
• Expr.meta.output_name for struct fields (#24064)
• Ensure upcast operations on pl.Date default to microsecond precision (#23981)
• Add peak_{min,max} support for booleans (#24068)
• Planner output type for mean with strange input type (#24052)
• Remove, deprecate or change eager Exprs to be lazy compatible (#24027)
• Scan of multiple sources with null datatype (#24065)
• Categorical in nested data in row encoding (#24051)
• Missing length update in builder for pl.Array repetition (#24055)
• Race condition in global categories init (#24045)
• Revert "fix: Don't encode entire CategoricalMapping when going to Arrow (#24036)" (#24044)
• Error when using named functions (#24041)
• Don't encode entire CategoricalMapping when going to Arrow (#24036)
• Fix cast on arithmetic with lit (#23941)
• Incorrect slice-slice pushdown (#24032)
• Dedup common cache subplan in IR graph (#24028)
• Allow join on Decimal in in-memory engine (#24026)
• Fix datatypes for eval.list in aggregation context (#23911)
• Allocator capsule fallback panic (#24022)
• Accept another zlib "magic header" file signature (#24013)
• Fix truediv dtypes so cast in list.eval is not dropped (#23936)
• Don't reuse cached return_dtype for expanded map expressions (#24010)
• Cache id is not a valid dot node id (#24005)
• Align map_elements with and without return_dtype (#24007)
• Fix column dtype lifetime for csv_write segfault on Categorical (#23986)
• Allow serializing LazyGroupBy.map_groups (#23964)
• Correct allocator name in PyCapsule (#23968)
• Mismatched types for write function for windows (#23915)
• Fix unpivot panic when index= column not found (#23958)
• Fix assert_frame_equal with check_dtypes=False for all-null series with different types (#23943)
• Return correct python package version (#23951)
• Categorical namespace functions fail on Enum columns (#23925)
• Properly set sumwise complete on filter for missing columns (#23877)
• Restore Arrow-FFI-based Python<->Rust conversion in pyo3-polars (#23881)
• Group By with filters (#23917)
• Fix read_csv ignoring Decimal schema for header-only data (#23886)
• Ensure collect() native Iceberg always scans latest when no snapshot_id is given (#23907)
• Writing List(Array) columns to JSON without panic (#23875)
• Fill Iceberg missing fields with partition values if present in metadata (#23900)
• Create file for streaming sink even if unspawned (#23672)
• Update cloud testing environment (#23908)
• Parquet filtering on multiple RGs with literal predicate (#23903)
• Incorrect datatype passed to libc::write (#23904)
• Properly feature gate TZ_AWARE_RE usage (#23888)
• Improve identification of "non group-key" aggregates in SQL GROUP BY queries (#23191)
• Spawning tokio task outside reactor (#23884)
• Correctly raise DuplicateError on asof_join with suffix="" (#23864)
• Fix errors on native scan_iceberg (#23811)
• Fix index out of bounds panic filtering parquet (#23850)
• Fix error on empty range requests (#23844)
• Fix handling of hive partitioning hive_start_idx parameter (#23843)

📖 Documentation

• Rename avg_birthday -> avg_age in examples aggregation (#23726)
• Update Polars Cloud user guide (#24366)
• Update to Polars Cloud user guide (#24187)
• Update distributed page (#24323)
• Add Polars security policy (#24314)
• Fix few typos (#24305)
• Add missing reference to LazyFrame.pipe_with_schema() on the website (#24285)
• Fix formatting of Series.value_counts examples (#24245)
• Add DataFrame.map_columns to API (#24128)
• Update multiple pages in the Polars Cloud user guide (#23661)
• Improve StackOverflow links in contributing guide (#23895)
• Fix pyo3 documentation page link (#23839)
• Document the pureness requirements of udfs (#23787)

📦 Build system

• Re-enable macos-x86-64 (#24266)
• Drop binary support for macos_x86-64 (#24257)

🛠️ Other improvements

• Use PlanCallback in name.map_* (#24484)
• Replace unsafe with collect (#24494)
• Move dataset expansion to end and refactor not to use stack optimizer (#24457)
• Pin xlsvwriter to 3.2.5 or before (#24485)
• Add methods to EnumUnitVec and shorten name (#24415)
• Move CompressionUtils to polars-utils (#24430)
• Update github template to dispatch to cloud client (#24416)
• Bump c-api (#24412)
• Add a regression test for #7631 (#24363)
• Update cloud test InteractiveQuery to DirectQuery (#24287)
• Mark some tests as slow (#24327)
• Mark more tests as ready for cloud (#24315)
• Remove unnecessary stable_features for AVX512 (#24321)
• Remove PDS-H code (#24301)
• Get ready for even more cloud tests (#24292)
• Add tests for slices with caches (#24288)
• Readd ordering tests (#24284)
• Expand BitRepr to u8/u16 and use in in_memory group_by (#24248)
• Fix Makefile venv path (#24251)
• Remove unnecessary parentheses (#24244)
• Remove some transmutes (#24246)
• Wrap Py* data structures in polars-python in locks (#24209)
• Make non-nested shift{,_and_fill} ops generic (#24224)
• Remove unused Wrap (#24214)
• Propagate some python feature flags (#24201)
• Allow upcasting null-typed columns to nested column types in scans (#24185)
• Automatically label a few more types of PR (#24147)
• Update toolchain (#24156)
• InMemoryJoin should be coloured as InMemoryFallback (#24154)
• Fool-proof retrieve_error_msg (#24132)
• Add order_sensitive property for AExpr (#24116)
• Mark more tests as not possible on cloud (#24103)
• Turn AggExpr::Count from tuple to struct (#24096)
• Mark tests that may fail in cloud (#24067)
• Make CI perf failures more lenient (#24066)
• Fix hive partition string encoding in CI by upgrading deltalake (#24018)
• Avoid unreachable if dtype feature is not enabled (#24062)
• Make tests with sinks run on cloud again (#24048)
• Update pyo3-polars versions (#24031)
• Remove insert_error_function (#24023)
• Remove cache hits, clean up in-mem prefill (#24019)
• Use .venv instead of venv in pyo3-polars examples (#24024)
• Fix test failing mypy (#24017)
• Remove outdated comment (#23998)
• Add a _plr.pyi to remove mypy issues (#23970)
• Don't define CountStar as dyn OptimizationRule (#23976)
• Rename atol and rtol to abs_tol and rel_tol (#23961)
• Introduce Row{Encode,Decode} as FunctionExpr (#23933)
• Dispatch through pl.map_batches and AnonymousColumnsUdf (#23867)
• Ensure clippy and rustfmt run in CI when changing pyo3-polars (#23930)
• Split column_selector.rs (#23921)
• Fix pyo3-polars proc-macro re-exports (#23918)
• Make GetBatchState polling functions unsafe (#23795)
• Rewrite evaluate_on_groups for .gather / .get (#23700)
• Remove Context from logical layer (#23863)
• Add proptest strategy for Polars DataType schemas (#23854)
• Move Python C API to python-polars (#23876)
• Refactor directory structure of streaming multi-scan (#23865)
• Add subphase and query task spawning to StreamingExecState (#23725)
• Update Rust Polars versions (#23861)
• Make polars-parquet optional (#23860)
• Relax constraint on maximum Python version for numba (#23838)

Thank you to all our contributors for making this release possible!
@Gusabary, @JakubValtar, @Kevin-Patyk, @MarcoGorelli, @Matt711, @NeejWeej, @VictorAtIfInsurance, @agossard, @alexander-beedie, @aparna2198, @borchero, @c-peters, @camriddell, @cgevans, @cmdlineluser, @coastalwhite, @deanm0000, @dsprenkels, @eitsupi, @etiennebacher, @gab23r, @gfvioli, @henryharbeck, @iishutov, @itamarst, @jarondl, @jimmmmmmmmmmmy, @jjurm, @joshuamarkovic, @juansolm, @kdn36, @kuril, @math-hiyoko, @mcrumiller, @mpasa, @mrkn, @mroeschke, @nameexhaustion, @nesb1, @orlp, @pka, @pomo-mondreganto, @r-brink, @rawhuul, @ritchie46, @stijnherfst, @vdrn and @wence-