Polars 1.43.0：多项弃用与性能改进

⚠️ Deprecations

• Deprecate casting numeric types to categoricals (#28349)
• Deprecate cat.get_categories() and cat.to_local() (#28299)
• Deprecate LazyFrame.profile() (#28275)
• Deprecate casts from non-nested dtypes into Lists (#28193)
• Deprecate bitwise ops between integers and booleans (#28186)
• Deprecate list/arr.to_struct() calls that don't pass field names (#28243)
• Rename missing_utf8_is_empty_string to empty_string_is_null (#28173)

🚀 Performance improvements

• Split multiplexers that directly scan from in-memory DataFrame (#28376)
• Make DNS cache global (#28352)
• Do not remove cache if predicates not pushed to all inputs (#28341)
• Environment variable for logging slow DNS lookup (#28211)
• Pre-partition on left, right and semi joins on hive partitioned data (#28374)
• Rewrite inner joins on hive partitioned data to a union of partitions filtered joins (#28327)
• Tighten redundant comparisons and propagate filter constraints (#27999)
• Canonicalize predicates (#28212)
• Remove excess memory copy in streaming IPC sink (#28141)
• Parallelize scan_iceberg resolve (#28168)
• Chunk-aware morsel splitting on single-file IO sink (#27950)
• Don't allocate for full_null() with small lengths (#28181)
• Use monotonic deque for rolling min_by/max_by (O(n)) (#27436)

✨ Enhancements

• Pre-partition group-by on hive keys (#28444)
• Add ewm_sum and ewm_sum_by #28151 (#28215)
• Serve stale records from object_store DNS cache (#28256)
• Make partition_hive an opt flag (#28345)
• Add scan_arrow_c_stream (#28340)
• When displaying IRExprs, only add parentheses when needed for disambiguation (#28319)
• Support Iceberg field initial-default in native scan_iceberg (#28324)
• Show only differing dtypes in assert_frame_equal error (#27816)
• Expose ewm and rolling *_by expressions in Python visitor (#28286)
• More accurate rolling moments (#28309)
• Remove hard block on native scan for Iceberg V3 tables (#28277)
• Add Series.degrees/radians and clarify trig functions use radians (#22961)
• Merge sorted with multikey (#28067)
• Add list expression which consistently packs elements together into new List type (#27990)
• Add read_database Arrow fast-path for "python-oracledb" (#28230)
• Optimize joins with redundant equi-join keys (#28017)
• Implement missing datetime options for CastColumnsPolicy (#28084)
• Add Expr.cat.to and Expr.cat.physical (#28096)
• Add POLARS_OOC_DISK_BUDGET_MB (#28045)
• Add build side preference parameter for join (#28154)

🐞 Bug fixes

• Avoid panic when union slice skips all rows (#28420)
• Solve panic in dt.replace when there were multiple chunks (#28437)
• Propagate is_scalar from the input to the output of .sort() and .sort_by() (#28438)
• Resolve CSV column names overwrite in DSL->IR conversion (#28383)
• Avoid IEJoin rewrite for Categorical comparisons (#28427)
• Do not rewrite sort().reverse() to sort(descending=True) when maintain_order=True (#28403)
• Ensure BinaryView offset+len does not exceed i32::MAX where possible (#28048)
• Invalid offset in strptime (#28388)
• Incorrect schema type for decimal <-> primitive division (#28373)
• Panic in in-memory CSEE handling (#28371)
• Fix offset in arrow ffi export of sliced struct arrays (#28369)
• Fix cross filter not applied with sink and CSE (#28297)
• Fix panic on projection pushdown with caches (#28280)
• Fix write_json() null values in Array columns being written incorrectly as null (#28330)
• Fix EntityTooSmall on sink_ipc to S3 (#28255)
• Raise error instead of silent wrapping for select(len()) (#28355)
• Float16 groupby aggregates (#28361)
• Respect lexical ordering of Categorical in top_k/bottom_k (#28359)
• Support dtype-list schema overrides in scan_csv (#28226)
• Resolve unknown type in fused multiply add (#28321)
• Honor aws_checksum_algorithm when provided (#28328)
• Remove usage of deprecated pyarrow.feather.read_table (#28323)
• Fix regression in sourcing HF_TOKEN (#28317)
• Raise on addition/subtraction between temporal and non-temporal Series (#28266)
• Avoid panic constructing Series from unaligned numpy arrays (#28120)
• Rewrite with_columns on empty df to select during DSL -> IR (#28298)
• Fix sink deadlock regression (#28296)
• Avoid panic when consumer of vertical concat is done (#28272)
• Harden IPC mmap API (#28258)
• Classify S3 region request failures as IO errors (#28225)
• Incorrect inner dtype in ArrayChunked::from_aligned_values (#28249)
• Raise on implode of Object dtype instead of creating invalid List(Object) (#28246)
• Return null not 0 for the first unbiased ewm_var/ewm_std value (#28235)
• Database appends with ADBC shouldn't require "CREATE" privileges unless the table is confirmed not to exist (#28228)
• Avoid slice pushdown panic on shared cache inputs (#28157)
• Incorrect dtype for Unknown right literal in arithmetic (#28184)
• Remove unnecessary unsafe Python object downcast (#28189)
• Normalize non-native byte order in numpy array construction (#28197)
• Use-after-free in numpy ufunc FFI (#28195)
• Unpickling for pl.when().then() (#28165)
• Reduce unknown casts (#28145)
• Consider a rolling_rank position invalid if ost.len() < min_samples (#28142)
• Incorrect broadcast with empty len in pl.concat_list (#28134)

📖 Documentation

• Update comparison page (#28418)
• Update GPU support documentation with the cudf-polars 26.06 release (#27830)
• Fix dev docs being canonical for SEO (#28306)
• Document experimental HDFS support on-premises (#28115)
• Add Series.degrees/radians and clarify trig functions use radians (#22961)
• Add polars-bio to community plugins (#28103)
• Add AWS Marketplace walkthrough to Cloud User Guide (#28214)
• Correct merge_sorted() docs also for DataFrame (#28183)
• Clarify DataFrame.remove combines predicates with AND (#28171)
• Update config reference (#28150)
• Correct that merge_sorted() null inputs should be nulls first (#28177)
• Clarify parts of the Polars Cloud and On-prem user guide (#28170)
• Add On-Premise release 0.6.3 to releases page (#28175)
• Update PolarsCloud snippets for 0.9.0 release (#28166)
• Fix to_titlecase incorrectly claiming alphanumeric separation (#28136)

📦 Build system

• Set the default dev profile to line-tables-only (#28358)
• Reduce binary size by optimizing for size in the SQL transpilation (#28336)

🛠️ Other improvements

• Update AI policy for comments (#28436)
• Fix flaky ordering expectation in top_k_by (#28435)
• Ignore all deprecation warnings in Python doctest (#28398)
• Re-work shuffle parameter for sample() (#27460)
• Ignore deprecation warnings on to_struct() in doctest (#28370)
• Update spin dependency to v0.10.1 (#28360)
• Bloat dispatch reduction (#28337)
• Show only differing dtypes in assert_frame_equal error (#27816)
• Accept IR in optimize (#28318)
• Annotate untyped module constants (#27907)
• Remove unencountered deny entries (#28260)
• Bump crossbeam-epoch dependency (#28259)
• Change object_store custom DNS resolver patch to rev-based (#28241)
• Mark shape tests as passing (#28133)
• Attribute annotations for *GroupBy (#27903)
• Clarify AI policy, explicitly forbid agents from interacting with our repository (#28206)
• Tighten first-time-contributor screenshot requirements (#28207)
• Covariant classinstmethod and attribute annotation (#27904)
• Ignore quickxml DoS rustsec (#28185)
• Update typos to v1.48.0 (#28162)

Thank you to all our contributors for making this release possible!