fix: Fix decimal dyn float supertype (pola-rs#17464)

Wouittone · Jul 6, 2024 · a9fb237 · a9fb237
1 parent 2c1836b
commit a9fb237
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Showing 2 changed files with 10 additions and 4 deletions.
diff --git a/crates/polars-core/src/utils/supertype.rs b/crates/polars-core/src/utils/supertype.rs
@@ -276,11 +276,11 @@ pub fn get_supertype_with_options(
             },
             (dt, Unknown(kind)) => {
                 match kind {
-                    // numeric vs float|str -> always float|str
-                    UnknownKind::Float | UnknownKind::Int(_) if dt.is_float() | dt.is_string() => Some(dt.clone()),
+                    // numeric vs float|str -> always float|str|decimal
+                    UnknownKind::Float | UnknownKind::Int(_) if dt.is_float() | dt.is_string() | dt.is_decimal() => Some(dt.clone()),
                     UnknownKind::Float if dt.is_integer() => Some(Unknown(UnknownKind::Float)),
-                    // Materialize float
-                    UnknownKind::Float if dt.is_float() => Some(dt.clone()),
+                    // Materialize float to float or decimal
+                    UnknownKind::Float if dt.is_float() | dt.is_decimal() => Some(dt.clone()),
                     // Materialize str
                     UnknownKind::Str if dt.is_string() | dt.is_enum() => Some(dt.clone()),
                     // Materialize str

diff --git a/py-polars/tests/unit/datatypes/test_decimal.py b/py-polars/tests/unit/datatypes/test_decimal.py
@@ -479,3 +479,9 @@ def test_decimal_raise_oob_precision() -> None:
     # max precision is 38.
     with pytest.raises(pl.exceptions.InvalidOperationError):
         df.select(b=pl.col("a").cast(pl.Decimal(76, 38)))
+
+
+def test_decimal_dynamic_float_st() -> None:
+    assert pl.LazyFrame({"a": [D("2.0"), D("0.5")]}).filter(
+        pl.col("a").is_between(0.45, 0.9)
+    ).collect().to_dict(as_series=False) == {"a": [D("0.5")]}