Introduce version file so we can conditionally handle things in tests (…

…#16280)

We decided we would attempt to support a range of versions back to 1.0. We'll test with oldest and newest versions we support. To facilitate, introduce some versioning constants.

Authors:
  - Lawrence Mitchell (https://github.com/wence-)

Approvers:
  - Thomas Li (https://github.com/lithomas1)

URL: #16280

python/cudf_polars/cudf_polars/dsl/ir.py

@@ -313,7 +313,12 @@ def evaluate(self, *, cache: MutableMapping[int, DataFrame]) -> DataFrame:
             raise NotImplementedError(
                 f"Unhandled scan type: {self.typ}"
             )  # pragma: no cover; post init trips first
-        if row_index is not None:
+        if (
+            row_index is not None
+            # TODO: remove condition when dropping support for polars 1.0
+            # https://github.com/pola-rs/polars/pull/17363
+            and row_index[0] in self.schema
+        ):
             name, offset = row_index
             dtype = self.schema[name]
             step = plc.interop.from_arrow(

python/cudf_polars/cudf_polars/utils/versions.py

@@ -0,0 +1,28 @@
+# SPDX-FileCopyrightText: Copyright (c) 2024 NVIDIA CORPORATION & AFFILIATES.
+# SPDX-License-Identifier: Apache-2.0
+
+"""Version utilities so that cudf_polars supports a range of polars versions."""
+
+# ruff: noqa: SIM300
+from __future__ import annotations
+
+from packaging.version import parse
+
+from polars import __version__
+
+POLARS_VERSION = parse(__version__)
+
+POLARS_VERSION_GE_10 = POLARS_VERSION >= parse("1.0")
+POLARS_VERSION_GE_11 = POLARS_VERSION >= parse("1.1")
+POLARS_VERSION_GE_12 = POLARS_VERSION >= parse("1.2")
+POLARS_VERSION_GT_10 = POLARS_VERSION > parse("1.0")
+POLARS_VERSION_GT_11 = POLARS_VERSION > parse("1.1")
+POLARS_VERSION_GT_12 = POLARS_VERSION > parse("1.2")
+
+POLARS_VERSION_LE_12 = POLARS_VERSION <= parse("1.2")
+POLARS_VERSION_LE_11 = POLARS_VERSION <= parse("1.1")
+POLARS_VERSION_LT_12 = POLARS_VERSION < parse("1.2")
+POLARS_VERSION_LT_11 = POLARS_VERSION < parse("1.1")
+
+if POLARS_VERSION < parse("1.0"):  # pragma: no cover
+    raise ImportError("cudf_polars requires py-polars v1.0 or greater.")

python/cudf_polars/tests/test_scan.py

@@ -10,6 +10,7 @@
     assert_gpu_result_equal,
     assert_ir_translation_raises,
 )
+from cudf_polars.utils import versions
 
 
 @pytest.fixture(
@@ -97,6 +98,10 @@ def test_scan_unsupported_raises(tmp_path):
     assert_ir_translation_raises(q, NotImplementedError)
 
 
+@pytest.mark.xfail(
+    versions.POLARS_VERSION_LT_11,
+    reason="https://github.com/pola-rs/polars/issues/15730",
+)
 def test_scan_row_index_projected_out(tmp_path):
     df = pl.DataFrame({"a": [1, 2, 3]})