pola-rs/polars · error

Comparison of FixedSizeListArray is not supported without dt

Error message

Comparison of FixedSizeListArray is not supported without dtype-array feature

What it means

todo!() in the comparison dispatch: FixedSizeListArray comparison requires the dtype-array compile feature, which is disabled in this build. Rebuild with the dtype-array feature to compare fixed-size-list columns.

Source

Thrown at crates/polars-compute/src/comparisons/list.rs:185

            PH::Primitive(PR::UInt8) => call_binary!(PrimitiveArray<u8>),
            PH::Primitive(PR::UInt16) => call_binary!(PrimitiveArray<u16>),
            PH::Primitive(PR::UInt32) => call_binary!(PrimitiveArray<u32>),
            PH::Primitive(PR::UInt64) => call_binary!(PrimitiveArray<u64>),
            PH::Primitive(PR::UInt128) => call_binary!(PrimitiveArray<u128>),
            PH::Primitive(PR::Float16) => call_binary!(PrimitiveArray<pf16>),
            PH::Primitive(PR::Float32) => call_binary!(PrimitiveArray<f32>),
            PH::Primitive(PR::Float64) => call_binary!(PrimitiveArray<f64>),
            PH::Primitive(PR::Int256) => call_binary!(PrimitiveArray<i256>),
            PH::Primitive(PR::DaysMs) => call_binary!(PrimitiveArray<days_ms>),
            PH::Primitive(PR::MonthDayNano) => {
                call_binary!(PrimitiveArray<months_days_ns>)
            },
            PH::Primitive(PR::MonthDayMillis) => unimplemented!(),

            #[cfg(feature = "dtype-array")]
            PH::FixedSizeList => call_binary!(arrow::array::FixedSizeListArray),
            #[cfg(not(feature = "dtype-array"))]
            PH::FixedSizeList => todo!(
                "Comparison of FixedSizeListArray is not supported without dtype-array feature"
            ),

            PH::Null => call_binary!(NullArray),
            PH::FixedSizeBinary => call_binary!(FixedSizeBinaryArray),
            PH::Binary => call_binary!(BinaryArray<i32>),
            PH::LargeBinary => call_binary!(BinaryArray<i64>),
            PH::Utf8 => call_binary!(Utf8Array<i32>),
            PH::LargeUtf8 => call_binary!(Utf8Array<i64>),
            PH::List => call_binary!(ListArray<i32>),
            PH::LargeList => call_binary!(ListArray<i64>),
            PH::Struct => call_binary!(StructArray),
            PH::Union => todo!("Comparison of UnionArrays is not yet supported"),
            PH::Map => todo!("Comparison of MapArrays is not yet supported"),
            PH::Dictionary(I::Int8) => call_binary!(DictionaryArray<i8>),
            PH::Dictionary(I::Int16) => call_binary!(DictionaryArray<i16>),
            PH::Dictionary(I::Int32) => call_binary!(DictionaryArray<i32>),
            PH::Dictionary(I::Int64) => call_binary!(DictionaryArray<i64>),

View on GitHub (pinned to 9b5d73fd00)

Solutions

  1. Enable the `dtype-array` cargo feature to get FixedSizeListArray comparison support.
  2. Convert the fixed-size-list column to a regular List column, which has comparison support without the feature.
Defensive patterns

Strategy: fallback

When it happens

Trigger: This panic/expect fires when execution reaches an unguarded state described by: "Comparison of FixedSizeListArray is not supported without dtype-array feature". Typical triggers: unsupported dtype or feature-gated code path reached at runtime, invalid user input or environment variable value, calling API methods in the wrong order or on mismatched types, or data (lengths, offsets, ranges) violating the function's preconditions.

Common situations: Encountered when input data or configuration does not meet the preconditions of the throwing code path ("Comparison of FixedSizeListArray is not supported without dtype-array feature"). Common cases: missing Cargo feature flags, mismatched dtypes/lengths between arrays or series, out-of-range temporal values, malformed environment variables, or operations on unsupported/complex nested types.

AI-assisted analysis of pola-rs/polars@9b5d73fd00 (2026-08-19). Data as JSON: /api/errors/c8e7c65d534b55fe. Report an issue: GitHub.