Support Polars' Int128 / UInt128 (#299)

Related to #104

Author: evertlammerts

duckdb/polars_io.py

@@ -207,10 +207,12 @@ def _pl_tree_to_sql(tree: _ExpressionTree) -> str:
             "Int16",
             "Int32",
             "Int64",
+            "Int128",
             "UInt8",
             "UInt16",
             "UInt32",
             "UInt64",
+            "UInt128",
             "Float32",
             "Float64",
             "Boolean",

tests/fast/arrow/test_polars.py

@@ -681,6 +681,30 @@ def test_invalid_expr_json(self):
         with pytest.raises(AssertionError, match="The col name of a Column should be a str but got"):
             _pl_tree_to_sql(json.loads(bad_type_expr))
 
+    @pytest.mark.parametrize(
+        ("dtype", "test_value"),
+        [
+            (pl.Int8, 1),
+            (pl.Int16, 1),
+            (pl.Int32, 1),
+            (pl.Int64, 1),
+            (pl.Int128, 1),
+            (pl.UInt8, 1),
+            (pl.UInt16, 1),
+            (pl.UInt32, 1),
+            (pl.UInt64, 1),
+            (pl.UInt128, 1),
+            (pl.Float32, 1.0),
+            (pl.Float64, 1.0),
+            (pl.Boolean, True),
+        ],
+    )
+    def test_scalar_type_pushdown(self, dtype, test_value):
+        """Verify that literals of each scalar type can be pushed down."""
+        expr = pl.col("a") == pl.lit(test_value, dtype=dtype)
+        sql_expression = _predicate_to_expression(expr)
+        assert sql_expression is not None, f"Pushdown failed for {dtype}"
+
     def test_decimal_scale(self):
         scalar_decimal_no_scale = """
           { "Scalar": {