MNT remove old fix for polars version 0.20 (#182)

* MNT remove old fix for polars version 0.20

* TST skip test_compute_marginal for failing polars versions

src/model_diagnostics/calibration/identification.py

@@ -374,24 +374,14 @@ def compute_bias(
                     )
                     .sort("__priority", descending=True)
                     .head(n_bins)
-                )
-                # FIXME: When n_bins=0, the result should be an empty dataframe
-                # (0 rows and some columns). For some unknown reason as of
-                # polars 0.20.20, the following sort neglects the head(0) statement.
-                # Therefore, we place an explicit collect here. This should not be
-                # needed!
-                if n_bins == 0 or feature.null_count() >= 1:
-                    df = df.collect().lazy()
-                df = df.sort(feature_name, descending=False)
-
-                df = df.select(
-                    [
+                    .sort(feature_name, descending=False)
+                    .select(
                         pl.col(feature_name),
                         pl.col("bias_mean"),
                         pl.col("bias_count"),
                         pl.col("bias_weights"),
                         pl.col("bias_stderr"),
-                    ]
+                    )
                 ).collect()
 
                 # if is_categorical:

src/model_diagnostics/calibration/tests/test_identification.py

@@ -3,6 +3,7 @@
 import numpy as np
 import polars as pl
 import pytest
+from packaging.version import Version
 from polars.testing import assert_frame_equal, assert_series_equal
 from scipy.special import stdtr
 from scipy.stats import expectile, ttest_1samp
@@ -633,6 +634,11 @@ def test_compute_marginal(feature, f_grouped, bin_edges):
         )
         if bin_edges is not None:
             df_expected = df_expected.hstack([bin_edges.alias("bin_edges")])
+
+            if Version("1.11.0") <= Version(pl.__version__) <= Version("1.12"):
+                # See https://github.com/pola-rs/polars/issues/19482
+                pytest.skip()
+
         df_expected = df_expected.sort("feature")
         assert_frame_equal(df_marginal, df_expected, check_exact=False)