Remove pyarrow bug workaround

protarrow/cast_to_proto.py

@@ -126,19 +126,18 @@ def _cast_array(
 
         # TODO: remove when https://github.com/apache/arrow/issues/40750 is fixed
         #  and library is pinned to pyarrow>=17.0.0
-        offsets = maybe_copy_offsets(array.offsets)
         keys = _cast_array(keys, key_field, config)
         values = _cast_array(values, value_field, config)
 
         if config.map_as_list:
             return _map_as_list_from_arrays(
-                offsets=offsets,
+                offsets=array.offsets,
                 keys=keys,
                 values=values,
                 config=config,
             )
         else:
-            return pa.MapArray.from_arrays(offsets, keys, values).cast(
+            return pa.MapArray.from_arrays(array.offsets, keys, values).cast(
                 pa.map_(
                     keys.type,
                     pa.field(
@@ -251,11 +250,3 @@ def cast_table(
         ],
         proto_schema,
     )
-
-
-def maybe_copy_offsets(offsets: pa.Array) -> pa.Array:
-    if offsets.offset != 0:
-        # TODO: this it not efficient, find a way to copy in arrow
-        return pa.array(offsets.to_pylist(), offsets.type)
-    else:
-        return offsets

pyproject.toml

@@ -24,7 +24,7 @@ classifiers = [
   "Programming Language :: Python :: 3.14",
 ]
 dynamic = [ "version" ]
-dependencies = [ "googleapis-common-protos", "protobuf", "pyarrow" ]
+dependencies = [ "googleapis-common-protos", "protobuf", "pyarrow>=17" ]
 urls."Bug Tracker" = "https://github.com/tradewelltech/protarrow/issues"
 urls.Changelog = "https://github.com/tradewelltech/protarrow/blob/main/CHANGELOG.md"
 documentation = "https://protarrow.readthedocs.io/en/latest/"

tests/test_conversion.py

@@ -23,7 +23,6 @@
     cast_table,
     get_arrow_default_value,
     get_casted_array,
-    maybe_copy_offsets,
 )
 from protarrow.common import M, ProtarrowConfig, offset_values_array
 from protarrow.message_extractor import MessageExtractor
@@ -799,6 +798,8 @@ def test_cast_map_offset():
     )
     assert _cast_array(from_array, field, ProtarrowConfig()) == to_array
 
+    # Test it works with offset array / slice views.
+    # https://github.com/apache/arrow/issues/40750
     assert _cast_array(from_array[1:], field, ProtarrowConfig()) == to_array[1:]
 
 
@@ -825,18 +826,6 @@ def test_cast_list_offset():
     assert _cast_array(from_array[1:], field, ProtarrowConfig()) == to_array[1:]
 
 
-def test_maybe_copy_offsets():
-    array = pa.array([1, 2, 3], pa.int32())
-    assert maybe_copy_offsets(array) is array  # no copy
-    view = array[1:]
-    copy = maybe_copy_offsets(array[1:])
-    assert copy == view
-    assert copy is not view  # copy
-    assert copy.offset == 0
-    # Sadly pa.array is highly optimized
-    assert pa.array(array) is array
-
-
 def test_map_cast():
     array = pa.array(
         [