featrs

Issues somebody may already be working on are listed last. List everything by date

• KBinsDiscretizer and PolynomialFeatures accept colliding generated names, fail at transform

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  bug help wanted

  Difficulty 3/5 1-2 days Newbie friendliness 70/100

  featrs/featrs#209 · Opened Oct 31, 2026

  Maintainers usually reply within 3 days

• LogTransformer::method() after fit applies a new method to old validation

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  bug help wanted

  Difficulty 2/5 1-3 hours Newbie friendliness 78/100

  featrs/featrs#208 · Opened Oct 31, 2026

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• PolynomialFeatures silently drops every non-Float64 column

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  bug help wanted

  Difficulty 3/5 1-2 days Newbie friendliness 64/100

  featrs/featrs#207 · Opened Oct 31, 2026

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• AutoTypeDetector::fit succeeds on a 0-column frame

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  bug help wanted

  Difficulty 2/5 1-3 hours Newbie friendliness 85/100

  featrs/featrs#206 · Opened Oct 31, 2026

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• AutoTypeDetector reorders output: encoded columns hoisted ahead of numeric columns

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  bug help wanted

  Difficulty 2/5 1-3 hours Newbie friendliness 85/100

  featrs/featrs#205 · Opened Oct 31, 2026

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• OneHotEncoder with drop_first skips the unseen-value check for 1-category columns

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  bug help wanted

  Difficulty 2/5 1-3 hours Newbie friendliness 82/100

  featrs/featrs#204 · Opened Oct 31, 2026

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• All-null String columns silently disappear in Ordinal/Count/Frequency encoders

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  bug help wanted

  Difficulty 3/5 1-2 days Newbie friendliness 56/100

  featrs/featrs#203 · Opened Oct 31, 2026

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• SimpleImputer records no fill for a column complete at fit time

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  bug help wanted

  Difficulty 2/5 1-3 hours Newbie friendliness 85/100

  featrs/featrs#202 · Opened Oct 31, 2026

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• QuantileTransformer jumps half the output range at a duplicated reference value

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  bug help wanted

  Difficulty 3/5 1-2 days Newbie friendliness 70/100

  featrs/featrs#201 · Opened Oct 31, 2026

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• MinMaxScaler::feature_range is unvalidated and re-read live after fit

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  bug help wanted

  Difficulty 3/5 1-2 days Newbie friendliness 68/100

  featrs/featrs#200 · Opened Oct 31, 2026

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• PowerTransformer stores non-finite mean/std and emits all-NaN/all-Inf

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  bug help wanted

  Difficulty 2/5 1-3 hours Newbie friendliness 77/100

  featrs/featrs#199 · Opened Oct 31, 2026

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• AutoTypeDetector.transform silently drops fitted numeric columns missing from the transform frame

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  bug help wanted

  Difficulty 2/5 1-3 hours Newbie friendliness 82/100

  featrs/featrs#198 · Opened Oct 31, 2026

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• OrdinalEncoder silently encodes unseen categories as null

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  bug help wanted

  Difficulty 3/5 1-2 days Newbie friendliness 65/100

  featrs/featrs#197 · Opened Oct 31, 2026

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• MissingIndicator silently overwrites a user column named {col}_missing

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  bug help wanted

  Difficulty 2/5 1-3 hours Newbie friendliness 85/100

  featrs/featrs#196 · Opened Oct 31, 2026

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• SimpleImputer counts NaN as a value, producing NaN fill statistics

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  bug help wanted Priority

  Difficulty 3/5 1-2 days Newbie friendliness 74/100

  featrs/featrs#194 · Opened Oct 31, 2026

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• LabelEncoder.transform does not bind to the fitted column (silent wrong output, column loss, panic on empty frame)

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  bug help wanted Priority

  Difficulty 3/5 1-2 days Newbie friendliness 68/100

  featrs/featrs#193 · Opened Oct 31, 2026

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• [audit follow-up] proptest / fuzz harness for numerical edge cases (tiny, huge, naninf)

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  help wanted testing

  Difficulty 4/5 3-5 days Newbie friendliness 42/100

  featrs/featrs#185 · Opened Oct 13, 2026

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• [audit supply-chain] quick-xml advisories + move cargo-audit ignores into committed audit.toml

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  dependencies help wanted

  Difficulty 3/5 1-3 hours Newbie friendliness 55/100

  featrs/featrs#184 · Opened Oct 13, 2026

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• [audit F-04] Inconsistent infinity handling across discretizers / scalers

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  bug help wanted

  Difficulty 5/5 Over a week Newbie friendliness 20/100

  featrs/featrs#183 · Opened Oct 13, 2026

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• [audit F-01] Absolute-epsilon degeneracy test collapses small-magnitude data

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  bug help wanted Priority

  Difficulty 4/5 3-5 days Newbie friendliness 38/100

  featrs/featrs#180 · Opened Oct 13, 2026

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• Integration-test coverage: 21+ public transformers have zero tests/ coverage; Pipeline & ColumnTransformer untested end-to-end

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  help wanted Priority testing

  Difficulty 3/5 1-2 days Newbie friendliness 85/100

  featrs/featrs#145 · Opened Aug 23, 2026

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• CHANGELOG [0.4.0] missing PowerTransformer entry

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  documentation help wanted

  Difficulty 1/5 Under an hour Newbie friendliness 93/100

  featrs/featrs#144 · Opened Aug 23, 2026

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• README transformer table missing PowerTransformer

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  documentation help wanted

  Difficulty 1/5 Under an hour Newbie friendliness 85/100

  featrs/featrs#143 · Opened Aug 23, 2026

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• GPU Backend — explore GPU acceleration for supported transformations

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  dependencies enhancement help wanted performance

  Difficulty 4/5 3-5 days Newbie friendliness 45/100

  featrs/featrs#93 · Opened Jul 9, 2026

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• DriftDetector — detect feature distribution drift between datasets

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  enhancement help wanted observability

  Difficulty 3/5 1-2 days Newbie friendliness 75/100

  featrs/featrs#92 · Opened Jul 9, 2026

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• Pipeline Versioning — track pipeline versions and schema compatibility

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  enhancement help wanted serialization

  Difficulty 4/5 3-5 days Newbie friendliness 44/100

  featrs/featrs#91 · Opened Jul 9, 2026

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• ONNX Export — export preprocessing pipelines to the ONNX format

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  dependencies enhancement help wanted

  Difficulty 4/5 3-5 days Newbie friendliness 45/100

  featrs/featrs#90 · Opened Jul 9, 2026

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• ExpressionTransformer — custom transformers via Polars expressions

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  enhancement help wanted

  Difficulty 2/5 1-3 hours Newbie friendliness 85/100

  featrs/featrs#89 · Opened Jul 9, 2026

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• AutoPipeline — auto-construct preprocessing pipelines from inferred data schemas

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  enhancement help wanted

  Difficulty 4/5 3-5 days Newbie friendliness 45/100

  featrs/featrs#85 · Opened Jul 9, 2026

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• FeatureNamesOut — trait providing consistent output feature names for every transformer

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  enhancement help wanted Priority refactor

  Difficulty 5/5 Over a week Newbie friendliness 35/100

  featrs/featrs#83 · Opened Jul 9, 2026

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• OnlineStatistics — running stats (Welford + optional T-Digest) without full dataset in memory

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  dependencies enhancement help wanted performance

  Difficulty 3/5 Half a day Newbie friendliness 75/100

  featrs/featrs#81 · Opened Jul 9, 2026

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• Streaming API — incremental fit/transform for datasets exceeding RAM

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  dependencies enhancement help wanted performance

  Difficulty 5/5 Over a week Newbie friendliness 35/100

  featrs/featrs#80 · Opened Jul 9, 2026

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• LazyFrame Support — execute transformers directly on Polars LazyFrames

  May be free again @aali2k7 claimed this 111 days ago, and no pull request is open. Open

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  enhancement help wanted performance Priority

  featrs/featrs#79 · 2 comments · 1 assignee · Opened Jul 9, 2026

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• Add serde + bincode model persistence via typetag (Phase 5, deferred)

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  dependencies enhancement help wanted serialization

  Difficulty 5/5 Over a week Newbie friendliness 25/100

  featrs/featrs#28 · Opened Jul 8, 2026

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• Add tracing step-level spans for Pipeline / ColumnTransformer (Phase 4)

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  dependencies enhancement help wanted observability

  Difficulty 3/5 1-2 days Newbie friendliness 68/100

  featrs/featrs#27 · Opened Jul 8, 2026

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• Use ahash in FeatureHasher with stable fixed seeds (Phase 3, breaking change)

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  dependencies enhancement help wanted performance

  Difficulty 4/5 3-5 days Newbie friendliness 48/100

  featrs/featrs#26 · Opened Jul 8, 2026

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• Add rayon for Normalizer::transform and FeatureHasher::transform (Phase 2, gated on #21/#24)

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  dependencies enhancement help wanted performance

  Difficulty 4/5 3-5 days Newbie friendliness 48/100

  featrs/featrs#25 · Opened Jul 8, 2026

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• Add Send + Sync to DataFrameTransformer supertrait

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  enhancement help wanted refactor

  Difficulty 2/5 1-3 hours Newbie friendliness 66/100

  featrs/featrs#23 · Opened Jul 8, 2026

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• Replace hand-rolled aggregations with Polars-native kernels (Phase 1)

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  enhancement help wanted performance refactor

  Difficulty 4/5 3-5 days Newbie friendliness 55/100

  featrs/featrs#24 · Opened Jul 8, 2026

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• Add criterion benchmarks (Phase 0 foundation)

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  benchmarks enhancement help wanted

  Difficulty 4/5 3-5 days Newbie friendliness 58/100

  featrs/featrs#21 · Opened Jul 8, 2026

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• Add proptest property-based tests for invariants

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  enhancement help wanted testing

  Difficulty 4/5 3-5 days Newbie friendliness 55/100

  featrs/featrs#22 · Opened Jul 8, 2026

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• Add [lints.rust] section for future-incompatible and nonstandard_style

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  enhancement help wanted

  Difficulty 1/5 1-3 hours Newbie friendliness 86/100

  featrs/featrs#19 · Opened Jul 7, 2026

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• Audit doc tests for valid executability

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  documentation help wanted

  Difficulty 3/5 1-2 days Newbie friendliness 74/100

  featrs/featrs#17 · Opened Jul 7, 2026

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• Promote missing_docs to deny and enforce intra-doc link integrity

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  documentation help wanted

  Difficulty 2/5 1-3 hours Newbie friendliness 78/100

  featrs/featrs#16 · Opened Jul 7, 2026

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• Remove redundant x.clone().select(...) calls in auto_type and column_transformer

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  enhancement help wanted

  Difficulty 2/5 1-3 hours Newbie friendliness 78/100

  featrs/featrs#15 · Opened Jul 7, 2026

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• Add [lints.clippy] to Cargo.toml with perf lints at deny level

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  enhancement help wanted

  Difficulty 2/5 1-3 hours Newbie friendliness 48/100

  featrs/featrs#14 · Opened Jul 7, 2026

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• Many transformers leave stale fitted state after a failed re-fit

  Possibly taken A pull request linked to this issue is open or already merged. Open

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  bug help wanted Priority

  Difficulty 4/5 3-5 days Newbie friendliness 65/100

  featrs/featrs#195 · Opened Oct 31, 2026

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