🐛 Bug Fixes

• We need this to pacify mypy (#20285) @wence-
• Purge non-empty nulls for the generated lists columns in data generation utility (#20283) @ttnghia
• Add Proxy for SparseAccessor (#20278) @galipremsagar
• Add private attributes for cudf.pandas proxy objects (#20276) @galipremsagar
• Pin ibis-framework<11.0.0 (#20267) @Matt711
• Pin deltalake in cudf-polars-polars-tests CI job (#20255) @TomAugspurger
• Add stream and mr arguments to Column.from_arrow type stub (#20244) @TomAugspurger
• Fix the host-device tdigest offsets by using cuda::std::span (#20220) @PointKernel
• Deallocation should be noexcept (#20219) @bdice
• Change stream_checking_resource_adaptor::do_deallocate to noexcept (#20218) @vyasr
• Fix a race condition in the decode of delta encoded Parquet columns (#20216) @vuule
• Handle NVMLError_NotSupported in cudf-polars (#20179) @TomAugspurger
• Require passing memory resources to from_libcudf methods (#20171) @vyasr
• Fix RMM JNI pinned_fallback_host_memory_resource for CCCL 3.1.0 (#20160) @bdice
• Fix arrow timestamp frequency cases in cudf.pandas (#20128) @galipremsagar
• Fix cudf.date_range with non-iso start and end date strings (#20116) @mroeschke
• Unproxy few unnecessary testing utilities in pandas (#20088) @galipremsagar
• Fix create_distinct_rows_column to create non-nullable columns (#20082) @davidwendt
• Handle missing nightly runs in pandas tests job (#20081) @galipremsagar
• Cast inputs to true division from decimal to float (#20077) @Matt711
• Copy attrs at correct place in DataFrame constructor (#20074) @galipremsagar
• Fix numpy ufunc for DataFrame (#20070) @galipremsagar
• Align decimal dtypes in predicate before conditional join (#20060) @Matt711
• Enable hash-groupby for decimal32/64 type and MEAN aggregation (#20040) @davidwendt
• Fix libcudf groupby benchmarks to not include internal cache (#20038) @davidwendt

📖 Documentation

• Add profiling guide (#20292) @bdice
• Add note that --rmm-async only affects distributed scheduler. (#20129) @bdice

🚀 New Features

• Implement ARGMIN and ARGMAX aggregations for reduction (#20207) @ttnghia
• Add remaining memory resources (#20197) @vyasr
• Add memory resources to scalars (#20196) @vyasr
• Skip decompression of pruned parquet pages (#20192) @mhaseeb123
• Add memory resources to replace, json, and hashing (#20150) @vyasr
• Support decimal literals in cudf-polars (#20147) @Matt711
• Add pylibcudf is_valid_reduce_aggregation API (#20145) @davidwendt
• Add memory resources to I/O modules (#20136) @vyasr
• Add memory resources to reduce, column, column_factories, and contiguous_split (#20135) @vyasr
• Passthrough unary ops through Parquet predicate pushdown (#20127) @mhaseeb123
• Add memory resource to all strings modules (#20123) @vyasr
• Add memory resources to all nvtext APIs (#20119) @vyasr
• Add an example to inspect parquet files and dump row group and page level metadata information (#20117) @mhaseeb123
• Allow multiple calls to cudf::initialize and cudf::deinitialize (#20111) @vuule
• Remove rounding from cudf java (#20110) @pmattione-nvidia
• Add memory resources to groupby, datetime, and lists modules (#20102) @vyasr
• Add memory resources to search, reshape, and partitioning module (#20101) @vyasr
• Add memory resources to rolling, sorting, and quantiles modules (#20099) @vyasr
• Add memory resources to binaryop, copying, and stream_compaction (#20059) @vyasr
• Add memory resources to unary, transform, and filling modules (#20054) @vyasr
• Support cum_sum(...).over(...) expressions in cudf-polars (#19908) @Matt711
• Support forward/backward filling null values in a grouped window context (#19907) @Matt711
• [FEA] Implement JIT Filter for read_parquet (#19831) @lamarrr
• Add an example to demonstrate the use of next-gen parquet reader to read a parquet file with highly selective filters (#19469) @mhaseeb123
• Rewrite JNI functions to use JNI_TRY/JNI_CATCH (#19053) @ttnghia
• Add support for maintain_order param in joins (#17698) @Matt711

🛠️ Improvements

• Add more Python type annotations to cudf/core (#20287) @mroeschke
• Skip mypy in pre-commit.ci (#20286) @bdice
• Remove extraneous host_memory_resource include (#20284) @bdice
• Add numpy to the mypy pre-commit environment (#20282) @vyasr
• Add MultiIndex.dtypes (#20279) @galipremsagar
• Add more type annotations to cudf/core/column subclasses (#20277) @mroeschke
• Handle unordered grouped windows properly for null filling and cum sums (#20275) @Matt711
• Unpin DuckDB and Ibis in cudf.pandas thirdparty tests (#20269) @mroeschke
• Enable sccache-dist connection pool (#20264) @trxcllnt
• Add ability to set the source_info of parquet_reader_options (#20253) @wence-
• Update ConfigOptions for rapidsmpf-streaming integration (#20252) @rjzamora
• Add arm testing of cudf.pandas unit tests (#20251) @vyasr
• Add pylibcudf to pre-commit linting and fix outstanding errors (#20250) @vyasr
• Change .str.starts/endswith with tuple argument to match any pattern instead of pairwise matching (#20249) @mroeschke
• Move and rename ScanPartitionPlan (#20248) @rjzamora
• Standardize setting StructDtype field names post libcudf conversion (#20235) @mroeschke
• Prevent accidental copies of expensive-to-copy object types (#20226) @vuule
• More mypy and docs fixes (#20224) @vyasr
• Configuration for which metrics are enabled during tracing (#20223) @TomAugspurger
• Fix parquet row number check for page bounds (#20217) @pmattione-nvidia
• Rename comparison_binop_generator to arg_minmax_binop_generator and corresponding file to nested_types_extrema_utils.cuh (#20212) @Copilot
• Fix various typing errors (#20205) @vyasr
• Stop using libcudf default parameters in pylibcudf (#20204) @vyasr
• Pin pydantic<2.12 in ci/test_cudf_polars_polars_tests.sh (#20200) @mroeschke
• Support binops between float scalar to decimal column (#20199) @mroeschke
• Add an overhead field to cudf-polars tracing (#20198) @TomAugspurger
• Remove DataFrame.apply_chunks, Groupby.apply_grouped (#20194) @mroeschke
• [pre-commit.ci] pre-commit autoupdate (#20189) @pre-commit-ci[bot]
• Revert "Temporarily disable conda-java-tests" (#20184) @bdice
• Don't assume cudf_polars benchmarking scale factor is always an integer (#20182) @mroeschke
• Remove unnecessary work from read_parquet_metadata (#20180) @vuule
• Reduce execution times for parquet dictionary tests (#20176) @mhaseeb123
• Skip filtering Parquet row groups with dictionaries if there are non-dict encoded pages (#20175) @mhaseeb123
• Improve performance of groupby tdigests gtests (#20173) @davidwendt
• Update to rapids-logger 0.2 (#20172) @bdice
• Split row operator header (#20166) @PointKernel
• Add PDSH benchmark runner for cudf.pandas (#20164) @mroeschke
• Temporarily disable conda-java-tests (#20162) @bdice
• Manual forward merger for Branch 25.12 - branch 25.10 (#20157) @galipremsagar
• [cudf-polars] CUDA stream (#20154) @madsbk
• Avoid NumericalColumn call from CategoricalColumn.children (#20153) @mroeschke
• Branch 25.12 merge branch 25.10 (#20152) @vyasr
• Make ListColumn._transform_leaves convert via pylibcudf (#20151) @mroeschke
• Make ColumnBase.as_*_column convert via pylibcudf (#20149) @mroeschke
• Make ColumnBase.deserialize construct via pylibcudf (#20142) @mroeschke
• Remove unused ColumnBase.view (#20141) @mroeschke
• Remove compatibility with nvCOMP versions before 5.0 (#20140) @vuule
• Adjust rmm pool handling in PDSH benchmarks (#20138) @TomAugspurger
• Fix slowdown in cudf-polars distributed tests (#20137) @TomAugspurger
• Disable async MR priming in cudf.pandas (#20133) @bdice
• Fix type annotations in cudf-polars (#20131) @TomAugspurger
• Add tests for AUTO and HYBRID (de)compression modes (#20126) @vuule
• Run cudf-polars wheels unit tests with more than 1 process (#20124) @mroeschke
• Add pyarrow stubs to mypy environment and fix associated errors (#20118) @vyasr
• Avoid running pandas unit tests for private functionality with cudf.pandas (#20115) @mroeschke
• Remove MultiIndex.from_pandas pytest benchmark (#20112) @mroeschke
• Use 8 processes for pandas tests, show top 10 test times (#20109) @bdice
• Reduce verbosity of running the pandas test suite (#20107) @vyasr
• Switch host_vector and host_span dependency (#20106) @davidwendt
• Make Column.set_mask go through pylibcudf (#20103) @mroeschke
• Have ListColumn.from_sequence go through pylibcudf (#20098) @mroeschke
• Deprecate legacy public row operators (#20097) @PointKernel
• Fix RAPIDS_BRANCH version and update script (#20091) @galipremsagar
• Reduce output buffer sizes for pruned pages of columns with a list parent (#20086) @mhaseeb123
• Avoid direct CategoricalColumn calls in dask_cudf (#20080) @mroeschke
• Rework reduction case statement as dispatch_type_and_aggregation (#20078) @davidwendt
• Avoid shadowing module names (#20071) @vyasr
• Fix typing issues in pylibcudf (#20069) @vyasr
• Avoid more explicit calls to IntervalColumn and StructColumn (#20064) @mroeschke
• Cleanup of some libcudf aggregation code (#20053) @davidwendt
• Prune entries in Sphinx nitpick_ignore (#20045) @mroeschke
• Deprecate .from_pandas constructor (#19996) @mroeschke
• Improve performance of string column size computation during parquet reads. (#19986) @nvdbaranec
• Run cudf-polars conda unit tests with more than 1 process (#19980) @mroeschke
• Clean up detail device atomic logic using atomic_ref (#19924) @PointKernel
• Pin polars version <1.34 and >=1.29 (#19912) @Matt711
• Trace node execution in cudf-polars (#19895) @TomAugspurger
• Cleanup parquet for simple columns (#19869) @pmattione-nvidia
• Update nvbench (#19619) @bdice
• Run polars tests with the streaming and in-memory executors (#19354) @Matt711
• Remove calling to purge_nonempty_nulls in make_lists_column (#12873) @ttnghia