fix avro and growable

crates/polars-arrow/src/array/growable/structure.rs

@@ -102,6 +102,7 @@ impl<'a> Growable<'a> for GrowableStruct<'a> {
         if let Some(validity) = &mut self.validity {
             validity.extend_constant(additional, false);
         }
+        self.length += additional;
     }
 
     #[inline]

crates/polars-arrow/src/io/avro/read/deserialize.rs

@@ -56,7 +56,7 @@ fn make_mutable(
                     .iter()
                     .map(|field| make_mutable(field.dtype(), None, capacity))
                     .collect::<PolarsResult<Vec<_>>>()?;
-                Box::new(DynMutableStructArray::new(values, 0, dtype.clone()))
+                Box::new(DynMutableStructArray::new(values, dtype.clone()))
                     as Box<dyn MutableArray>
             },
             other => {

crates/polars-arrow/src/io/avro/read/nested.rs

@@ -217,10 +217,10 @@ pub struct DynMutableStructArray {
 }
 
 impl DynMutableStructArray {
-    pub fn new(values: Vec<Box<dyn MutableArray>>, length: usize, dtype: ArrowDataType) -> Self {
+    pub fn new(values: Vec<Box<dyn MutableArray>>, dtype: ArrowDataType) -> Self {
         Self {
             dtype,
-            length,
+            length: 0,
             values,
             validity: None,
         }
@@ -243,11 +243,11 @@ impl DynMutableStructArray {
     #[inline]
     fn push_null(&mut self) {
         self.values.iter_mut().for_each(|x| x.push_null());
+        self.length += 1;
         match &mut self.validity {
             Some(validity) => validity.push(false),
             None => self.init_validity(),
         }
-        self.length += 1;
     }
 
     fn init_validity(&mut self) {

py-polars/tests/unit/datatypes/test_struct.py

@@ -1,13 +1,13 @@
 from __future__ import annotations
 
+import io
 from dataclasses import dataclass
 from datetime import datetime, time
 from typing import TYPE_CHECKING
 
 import pandas as pd
 import pyarrow as pa
 import pytest
-import io
 
 import polars as pl
 import polars.selectors as cs
@@ -1084,12 +1084,14 @@ def test_zfs_nullable_when_otherwise() -> None:
     df = pl.DataFrame([a, b])
 
     df = df.select(
-        x = pl.when(pl.col.a.is_not_null()).then(pl.col.a).otherwise(pl.col.b),
-        y = pl.when(pl.col.a.is_null()).then(pl.col.a).otherwise(pl.col.b),
+        x=pl.when(pl.col.a.is_not_null()).then(pl.col.a).otherwise(pl.col.b),
+        y=pl.when(pl.col.a.is_null()).then(pl.col.a).otherwise(pl.col.b),
     )
 
-    assert_series_equal(df['x'], pl.Series('x', [{}, {}, {}, {}, None], pl.Struct([])))
-    assert_series_equal(df['y'], pl.Series('y', [None, None, None, {}, None], pl.Struct([])))
+    assert_series_equal(df["x"], pl.Series("x", [{}, {}, {}, {}, None], pl.Struct([])))
+    assert_series_equal(
+        df["y"], pl.Series("y", [None, None, None, {}, None], pl.Struct([]))
+    )
 
 
 def test_zfs_struct_fns() -> None:
@@ -1098,13 +1100,13 @@ def test_zfs_struct_fns() -> None:
     assert a.struct.fields == []
 
     # @TODO: This should really throw an error as per #19132
-    assert a.struct.rename_fields(['a']).struct.unnest().shape == (1, 0)
+    assert a.struct.rename_fields(["a"]).struct.unnest().shape == (1, 0)
     assert a.struct.rename_fields([]).struct.unnest().shape == (1, 0)
 
-    assert_series_equal(a.struct.json_encode(), pl.Series('a', ["{}"], pl.String))
+    assert_series_equal(a.struct.json_encode(), pl.Series("a", ["{}"], pl.String))
 
 
-@pytest.mark.parametrize("format", ['binary', 'json'])
+@pytest.mark.parametrize("format", ["binary", "json"])
 @pytest.mark.parametrize("size", [0, 1, 2, 13])
 def test_zfs_serialization_roundtrip(format: pl.SerializationFormat, size: int) -> None:
     a = pl.Series("a", [{}] * size, pl.Struct([])).to_frame()
@@ -1125,13 +1127,7 @@ def test_zfs_row_encoding(size: int) -> None:
 
     df = pl.DataFrame([a, pl.Series("x", list(range(size)), pl.Int8)])
 
-    gb = (
-        df
-            .lazy()
-            .group_by(["a", "x"])
-            .agg(pl.all().min())
-            .collect(streaming=True)
-    )
+    gb = df.lazy().group_by(["a", "x"]).agg(pl.all().min()).collect(streaming=True)
 
     # We need to ignore the order because the group_by is undeterministic
     assert_frame_equal(gb, df, check_row_order=False)

py-polars/tests/unit/io/test_ipc.py

@@ -2,7 +2,7 @@
 
 import io
 from decimal import Decimal
-from typing import TYPE_CHECKING, Any, Dict
+from typing import TYPE_CHECKING, Any
 
 import pandas as pd
 import pytest
@@ -358,9 +358,9 @@ def test_ipc_variadic_buffers_categorical_binview_18636() -> None:
 
 @pytest.mark.parametrize("size", [0, 1, 2, 13])
 def test_ipc_chunked_roundtrip(size: int) -> None:
-    a = pl.Series("a", [{ 'x': 1 }] * size, pl.Struct({ 'x': pl.Int8 })).to_frame()
+    a = pl.Series("a", [{"x": 1}] * size, pl.Struct({"x": pl.Int8})).to_frame()
 
-    c = pl.concat([a] * 2, how='vertical')
+    c = pl.concat([a] * 2, how="vertical")
 
     f = io.BytesIO()
     c.write_ipc(f)
@@ -384,7 +384,7 @@ def test_zfs_ipc_roundtrip(size: int) -> None:
 def test_zfs_ipc_chunked_roundtrip(size: int) -> None:
     a = pl.Series("a", [{}] * size, pl.Struct([])).to_frame()
 
-    c = pl.concat([a] * 2, how='vertical')
+    c = pl.concat([a] * 2, how="vertical")
 
     f = io.BytesIO()
     c.write_ipc(f)
@@ -394,13 +394,15 @@ def test_zfs_ipc_chunked_roundtrip(size: int) -> None:
 
 
 @pytest.mark.parametrize("size", [0, 1, 2, 13])
-@pytest.mark.parametrize("value", [{}, { 'x': 1 }])
+@pytest.mark.parametrize("value", [{}, {"x": 1}])
 @pytest.mark.write_disk
-def test_memmap_ipc_chunked_structs(size: int, value: Dict[str, int], tmp_path: Path) -> None:
+def test_memmap_ipc_chunked_structs(
+    size: int, value: dict[str, int], tmp_path: Path
+) -> None:
     a = pl.Series("a", [value] * size, pl.Struct).to_frame()
 
-    c = pl.concat([a] * 2, how='vertical')
+    c = pl.concat([a] * 2, how="vertical")
 
-    f = tmp_path / 'f.ipc'
+    f = tmp_path / "f.ipc"
     c.write_ipc(f)
     assert_frame_equal(c, pl.read_ipc(f))

py-polars/tests/unit/io/test_json.py

@@ -438,7 +438,7 @@ def test_json_infer_3_dtypes() -> None:
     assert out.dtypes[0] == pl.List(pl.String)
 
 
-#NOTE: This doesn't work for 0, but that is normal
+# NOTE: This doesn't work for 0, but that is normal
 @pytest.mark.parametrize("size", [1, 2, 13])
 def test_zfs_json_roundtrip(size: int) -> None:
     a = pl.Series("a", [{}] * size, pl.Struct([])).to_frame()