refactor: Deprecate Expr.rechunk

crates/polars-plan/dsl-schema-hashes.json

@@ -57,7 +57,7 @@
   "FileSinkType": "0a884327bff2f9dbfb1bb81e2b226610158ec42fb6ed54e5c703468b7d519645",
   "FileType": "199c4fbfa07c8453dd03d341405b706227671b6c0374d884ef1c591724a991c3",
   "FillNullStrategy": "f5e7ae60e635bf1392b2d89c393e5feba024eff4e01285777c171d9deab34c9a",
-  "FunctionExpr": "85833a38b3976d402c38dc30e4323456ec7aa12a75a098e1ae3d246e6d65a667",
+  "FunctionExpr": "6325bf37441fe2a7a221aed6228c166003b3c9dff3221056d71b2db198e30cf5",
   "FunctionFlags": "4c779df23ee9eb07136cd532d7cfb1e3fcb6d4d2487435afed93295792fda053",
   "FunctionOptions": "c32d0c82e16d7b9f015431a335ce3e9aef52c4b2f22c461ff89ec757a36d3299",
   "GroupbyOptions": "4e2196af0abee06193739c82a471250f551bc93c81bd68d286263b0ad748ff64",

crates/polars-plan/src/dsl/function_expr/mod.rs

@@ -135,7 +135,6 @@ pub enum FunctionExpr {
         function_by: RollingFunctionBy,
         options: RollingOptionsDynamicWindow,
     },
-    Rechunk,
     Append {
         upcast: bool,
     },
@@ -464,7 +463,7 @@ impl Hash for FunctionExpr {
                 ignore_nulls.hash(state)
             },
             MaxHorizontal | MinHorizontal | DropNans | DropNulls | Reverse | ArgUnique | ArgMin
-            | ArgMax | Product | Shift | ShiftAndFill | Rechunk => {},
+            | ArgMax | Product | Shift | ShiftAndFill => {},
             Append { upcast } => upcast.hash(state),
             ArgSort {
                 descending,
@@ -710,7 +709,6 @@ impl Display for FunctionExpr {
             RollingExpr { function, .. } => return write!(f, "{function}"),
             #[cfg(feature = "rolling_window_by")]
             RollingExprBy { function_by, .. } => return write!(f, "{function_by}"),
-            Rechunk => "rechunk",
             Append { .. } => "upcast",
             ShiftAndFill => "shift_and_fill",
             DropNans => "drop_nans",

crates/polars-plan/src/dsl/mod.rs

@@ -222,11 +222,6 @@ impl Expr {
         self.map_binary(FunctionExpr::Append { upcast }, other.into())
     }
 
-    /// Collect all chunks into a single chunk before continuing.
-    pub fn rechunk(self) -> Self {
-        self.map_unary(FunctionExpr::Rechunk)
-    }
-
     /// Get the first `n` elements of the Expr result.
     pub fn head(self, length: Option<usize>) -> Self {
         self.slice(lit(0), lit(length.unwrap_or(10) as u64))

crates/polars-plan/src/plans/aexpr/function_expr/dispatch.rs

@@ -131,10 +131,6 @@ pub(super) fn drop_nulls(s: &Column) -> PolarsResult<Column> {
     Ok(s.drop_nulls())
 }
 
-pub fn rechunk(s: &Column) -> PolarsResult<Column> {
-    Ok(s.rechunk())
-}
-
 pub fn append(s: &[Column], upcast: bool) -> PolarsResult<Column> {
     assert_eq!(s.len(), 2);
 

crates/polars-plan/src/plans/aexpr/function_expr/mod.rs

@@ -185,7 +185,6 @@ pub enum IRFunctionExpr {
         function_by: IRRollingFunctionBy,
         options: RollingOptionsDynamicWindow,
     },
-    Rechunk,
     Append {
         upcast: bool,
     },
@@ -517,7 +516,7 @@ impl Hash for IRFunctionExpr {
                 ignore_nulls.hash(state)
             },
             MaxHorizontal | MinHorizontal | DropNans | DropNulls | Reverse | ArgUnique | ArgMin
-            | ArgMax | Product | Shift | ShiftAndFill | Rechunk => {},
+            | ArgMax | Product | Shift | ShiftAndFill => {},
             Append { upcast } => {
                 upcast.hash(state);
             },
@@ -766,7 +765,6 @@ impl Display for IRFunctionExpr {
             RollingExpr { function, .. } => return write!(f, "{function}"),
             #[cfg(feature = "rolling_window_by")]
             RollingExprBy { function_by, .. } => return write!(f, "{function_by}"),
-            Rechunk => "rechunk",
             Append { .. } => "append",
             ShiftAndFill => "shift_and_fill",
             DropNans => "drop_nans",
@@ -1140,7 +1138,6 @@ impl From<IRFunctionExpr> for SpecialEq<Arc<dyn ColumnsUdf>> {
                     include_breakpoint
                 )
             },
-            Rechunk => map!(dispatch::rechunk),
             Append { upcast } => map_as_slice!(dispatch::append, upcast),
             ShiftAndFill => {
                 map_as_slice!(shift_and_fill::shift_and_fill)
@@ -1457,7 +1454,6 @@ impl IRFunctionExpr {
             F::RollingExpr { .. } => FunctionOptions::length_preserving(),
             #[cfg(feature = "rolling_window_by")]
             F::RollingExprBy { .. } => FunctionOptions::length_preserving(),
-            F::Rechunk => FunctionOptions::length_preserving(),
             F::Append { .. } => FunctionOptions::groupwise(),
             F::ShiftAndFill => FunctionOptions::length_preserving(),
             F::Shift => FunctionOptions::length_preserving(),

crates/polars-plan/src/plans/aexpr/function_expr/schema.rs

@@ -95,7 +95,6 @@ impl IRFunctionExpr {
                     SumBy => mapper.sum_dtype(),
                 }
             },
-            Rechunk => mapper.with_same_dtype(),
             Append { upcast } => {
                 if *upcast {
                     mapper.map_to_supertype()

crates/polars-plan/src/plans/conversion/dsl_to_ir/functions.rs

@@ -731,7 +731,6 @@ pub(super) fn convert_functions(
                 options,
             }
         },
-        F::Rechunk => I::Rechunk,
         F::Append { upcast } => I::Append { upcast },
         F::ShiftAndFill => {
             polars_ensure!(&e[1].is_scalar(ctx.arena), ShapeMismatch: "'n' must be a scalar value");

crates/polars-plan/src/plans/conversion/ir_to_dsl.rs

@@ -821,7 +821,6 @@ pub fn ir_function_to_dsl(input: Vec<Expr>, function: IRFunctionExpr) -> Expr {
                 options,
             }
         },
-        IF::Rechunk => F::Rechunk,
         IF::Append { upcast } => F::Append { upcast },
         IF::ShiftAndFill => F::ShiftAndFill,
         IF::Shift => F::Shift,

crates/polars-plan/src/plans/functions/mod.rs

@@ -48,7 +48,6 @@ pub enum FunctionIR {
         columns: Arc<[PlSmallStr]>,
         separator: Option<PlSmallStr>,
     },
-    Rechunk,
     Explode {
         columns: Arc<[PlSmallStr]>,
         #[cfg_attr(feature = "ir_serde", serde(skip))]
@@ -80,7 +79,6 @@ impl PartialEq for FunctionIR {
     fn eq(&self, other: &Self) -> bool {
         use FunctionIR::*;
         match (self, other) {
-            (Rechunk, Rechunk) => true,
             (
                 FastCount {
                     sources: srcs_l, ..
@@ -120,7 +118,6 @@ impl Hash for FunctionIR {
                 columns.hash(state);
                 separator.hash(state);
             },
-            FunctionIR::Rechunk => {},
             FunctionIR::Explode { columns, schema: _ } => columns.hash(state),
             #[cfg(feature = "pivot")]
             FunctionIR::Unpivot { args, schema: _ } => args.hash(state),
@@ -141,7 +138,6 @@ impl FunctionIR {
     pub fn is_streamable(&self) -> bool {
         use FunctionIR::*;
         match self {
-            Rechunk => false,
             FastCount { .. } | Unnest { .. } | Explode { .. } => true,
             #[cfg(feature = "pivot")]
             Unpivot { .. } => true,
@@ -171,7 +167,7 @@ impl FunctionIR {
             OpaquePython(OpaquePythonUdf { predicate_pd, .. }) => *predicate_pd,
             #[cfg(feature = "pivot")]
             Unpivot { .. } => true,
-            Rechunk | Unnest { .. } | Explode { .. } => true,
+            Unnest { .. } | Explode { .. } => true,
             RowIndex { .. } | FastCount { .. } => false,
         }
     }
@@ -182,7 +178,7 @@ impl FunctionIR {
             Opaque { projection_pd, .. } => *projection_pd,
             #[cfg(feature = "python")]
             OpaquePython(OpaquePythonUdf { projection_pd, .. }) => *projection_pd,
-            Rechunk | FastCount { .. } | Unnest { .. } | Explode { .. } => true,
+            FastCount { .. } | Unnest { .. } | Explode { .. } => true,
             #[cfg(feature = "pivot")]
             Unpivot { .. } => true,
             RowIndex { .. } => true,
@@ -198,7 +194,7 @@ impl FunctionIR {
         }
     }
 
-    pub fn evaluate(&self, mut df: DataFrame) -> PolarsResult<DataFrame> {
+    pub fn evaluate(&self, df: DataFrame) -> PolarsResult<DataFrame> {
         use FunctionIR::*;
         match self {
             Opaque { function, .. } => function.call_udf(df),
@@ -215,10 +211,6 @@ impl FunctionIR {
                 cloud_options,
                 alias,
             } => count::count_rows(sources, scan_type, cloud_options.as_ref(), alias.clone()),
-            Rechunk => {
-                df.as_single_chunk_par();
-                Ok(df)
-            },
             Unnest { columns, separator } => {
                 feature_gated!(
                     "dtype-struct",
@@ -241,7 +233,6 @@ impl FunctionIR {
             FunctionIR::RowIndex { .. } => true,
             FunctionIR::FastCount { .. } => false,
             FunctionIR::Unnest { .. } => is_input_ordered,
-            FunctionIR::Rechunk => is_input_ordered,
             #[cfg(feature = "python")]
             FunctionIR::OpaquePython(..) => true,
             FunctionIR::Explode { .. } => true,
@@ -260,7 +251,6 @@ impl FunctionIR {
             Self::Unpivot { .. } => false,
             Self::RowIndex { .. }
             | Self::FastCount { .. }
-            | Self::Rechunk
             | Self::Explode { .. }
             | Self::Opaque { .. } => false,
         }
@@ -273,7 +263,7 @@ impl FunctionIR {
     /// Is the input ordering always the same as the output ordering.
     pub fn has_equal_order(&self) -> bool {
         match self {
-            Self::Unnest { .. } | Self::Rechunk => true,
+            Self::Unnest { .. } => true,
             #[cfg(feature = "python")]
             Self::OpaquePython(..) => false,
             #[cfg(feature = "pivot")]

crates/polars-plan/src/plans/functions/schema.rs

@@ -47,7 +47,6 @@ impl FunctionIR {
                 schema.insert_at_index(0, name, IDX_DTYPE)?;
                 Ok(Cow::Owned(Arc::new(schema)))
             },
-            Rechunk => Ok(Cow::Borrowed(input_schema)),
             Unnest { columns, separator } => {
                 #[cfg(feature = "dtype-struct")]
                 {

crates/polars-python/src/expr/general.rs

@@ -452,10 +452,6 @@ impl PyExpr {
         self.inner.clone().append(other.inner, upcast).into()
     }
 
-    fn rechunk(&self) -> Self {
-        self.inner.clone().rechunk().into()
-    }
-
     fn round(&self, decimals: u32, mode: Wrap<RoundMode>) -> Self {
         self.inner.clone().round(decimals, mode.0).into()
     }

crates/polars-python/src/lazyframe/visitor/expr_nodes.rs

@@ -572,7 +572,7 @@ pub(crate) fn into_py(py: Python<'_>, expr: &AExpr) -> PyResult<PyObject> {
                 },
                 LiteralValue::Scalar(sc) => {
                     match sc.as_any_value() {
-                        // AnyValue conversion of duration to python's
+                        // AnyValue conversion of duration to python'svis
                         // datetime.timedelta drops nanoseconds because
                         // there is no support for them. See
                         // https://github.com/python/cpython/issues/59648
@@ -1181,7 +1181,6 @@ pub(crate) fn into_py(py: Python<'_>, expr: &AExpr) -> PyResult<PyObject> {
                         return Err(PyNotImplementedError::new_err("rolling std by"));
                     },
                 },
-                IRFunctionExpr::Rechunk => ("rechunk",).into_py_any(py),
                 IRFunctionExpr::Append { upcast } => ("append", upcast).into_py_any(py),
                 IRFunctionExpr::ShiftAndFill => ("shift_and_fill",).into_py_any(py),
                 IRFunctionExpr::Shift => ("shift",).into_py_any(py),

crates/polars-python/src/lazyframe/visitor/nodes.rs

@@ -611,7 +611,6 @@ pub(crate) fn into_py(py: Python<'_>, plan: &IR) -> PyResult<PyObject> {
                     separator.as_ref().map(|s| s.to_string()),
                 )
                     .into_py_any(py)?,
-                FunctionIR::Rechunk => ("rechunk",).into_py_any(py)?,
                 FunctionIR::Explode { columns, schema: _ } => (
                     "explode",
                     columns.iter().map(|s| s.to_string()).collect::<Vec<_>>(),

py-polars/src/polars/_plr.pyi

@@ -1279,7 +1279,6 @@ class PyExpr:
     def gather_every(self, n: int, offset: int) -> PyExpr: ...
     def slice(self, offset: PyExpr, length: PyExpr) -> PyExpr: ...
     def append(self, other: PyExpr, upcast: bool) -> PyExpr: ...
-    def rechunk(self) -> PyExpr: ...
     def round(self, decimals: int, mode: Any) -> PyExpr: ...
     def round_sig_figs(self, digits: int) -> PyExpr: ...
     def floor(self) -> PyExpr: ...

py-polars/src/polars/expr/expr.py

@@ -1286,10 +1286,14 @@ def append(self, other: IntoExpr, *, upcast: bool = True) -> Expr:
         other_pyexpr = parse_into_expression(other)
         return wrap_expr(self._pyexpr.append(other_pyexpr, upcast))
 
+    @deprecated("`rechunk` is deprecated.")
     def rechunk(self) -> Expr:
         """
         Create a single chunk of memory for this Series.
 
+        .. versionchanged:: 1.35.0
+            The `rechunk` is deprecated and no longer affects chunking.
+
         Examples
         --------
         >>> df = pl.DataFrame({"a": [1, 1, 2]})
@@ -1311,7 +1315,7 @@ def rechunk(self) -> Expr:
         │ 2      │
         └────────┘
         """
-        return wrap_expr(self._pyexpr.rechunk())
+        return self
 
     def drop_nulls(self) -> Expr:
         """

py-polars/tests/unit/expr/test_exprs.py

@@ -392,7 +392,6 @@ def test_expression_appends() -> None:
     df = pl.DataFrame({"a": [1, 1, 2]})
 
     assert df.select(pl.repeat(None, 3).append(pl.col("a"))).n_chunks() == 2
-    assert df.select(pl.repeat(None, 3).append(pl.col("a")).rechunk()).n_chunks() == 1
 
     out = df.select(pl.concat([pl.repeat(None, 3), pl.col("a")], rechunk=True))