chore: enable pyright reportPossiblyUnboundVariable

narwhals/_duckdb/dataframe.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import contextlib
 from functools import reduce
 from operator import and_
 from typing import TYPE_CHECKING, Any, Iterator, Mapping, Sequence
@@ -47,9 +46,6 @@
     from narwhals.typing import AsofJoinStrategy, JoinStrategy, LazyUniqueKeepStrategy
     from narwhals.utils import _FullContext
 
-with contextlib.suppress(ImportError):  # requires duckdb>=1.3.0
-    from duckdb import SQLExpression
-
 
 class DuckDBLazyFrame(
     CompliantLazyFrame[
@@ -382,6 +378,8 @@ def unique(
                     "with `subset` specified."
                 )
                 raise NotImplementedError(msg)
+            from duckdb import SQLExpression
+
             # Sanitise input
             if any(x not in self.columns for x in subset_):
                 msg = f"Columns {set(subset_).difference(self.columns)} not found in {self.columns}."

narwhals/_duckdb/expr.py

@@ -1,6 +1,5 @@
 from __future__ import annotations
 
-import contextlib
 import operator
 from typing import TYPE_CHECKING, Any, Callable, Literal, Sequence, cast
 
@@ -46,9 +45,6 @@
     )
     from narwhals.utils import Version, _FullContext
 
-with contextlib.suppress(ImportError):  # requires duckdb>=1.3.0
-    from duckdb import SQLExpression
-
 
 class DuckDBExpr(LazyExpr["DuckDBLazyFrame", "Expression"]):
     _implementation = Implementation.DUCKDB
@@ -95,6 +91,8 @@ def _cum_window_func(
         reverse: bool,
         func_name: Literal["sum", "max", "min", "count", "product"],
     ) -> WindowFunction:
+        from duckdb import SQLExpression
+
         def func(window_inputs: WindowInputs) -> Expression:
             order_by_sql = generate_order_by_sql(
                 *window_inputs.order_by, ascending=not reverse
@@ -117,6 +115,8 @@ def _rolling_window_func(
         min_samples: int,
         ddof: int | None = None,
     ) -> WindowFunction:
+        from duckdb import SQLExpression
+
         ensure_type(window_size, int, type(None))
         ensure_type(min_samples, int)
         supported_funcs = ["sum", "mean", "std", "var"]
@@ -162,6 +162,7 @@ def broadcast(self, kind: Literal[ExprKind.AGGREGATION, ExprKind.LITERAL]) -> Se
         if self._backend_version < (1, 3):
             msg = "At least version 1.3 of DuckDB is required for binary operations between aggregates and columns."
             raise NotImplementedError(msg)
+        from duckdb import SQLExpression
 
         template = "{expr} over ()"
 
@@ -492,6 +493,8 @@ def null_count(self) -> Self:
 
     @requires.backend_version((1, 3))
     def over(self, partition_by: Sequence[str], order_by: Sequence[str] | None) -> Self:
+        from duckdb import SQLExpression
+
         if (window_function := self._window_function) is not None:
             assert order_by is not None  # noqa: S101
 
@@ -551,6 +554,8 @@ def round(self, decimals: int) -> Self:
 
     @requires.backend_version((1, 3))
     def shift(self, n: int) -> Self:
+        from duckdb import SQLExpression
+
         ensure_type(n, int)
 
         def func(window_inputs: WindowInputs) -> Expression:
@@ -565,6 +570,8 @@ def func(window_inputs: WindowInputs) -> Expression:
 
     @requires.backend_version((1, 3))
     def is_first_distinct(self) -> Self:
+        from duckdb import SQLExpression
+
         def func(window_inputs: WindowInputs) -> Expression:
             order_by_sql = generate_order_by_sql(*window_inputs.order_by, ascending=True)
             if window_inputs.partition_by:
@@ -581,6 +588,8 @@ def func(window_inputs: WindowInputs) -> Expression:
 
     @requires.backend_version((1, 3))
     def is_last_distinct(self) -> Self:
+        from duckdb import SQLExpression
+
         def func(window_inputs: WindowInputs) -> Expression:
             order_by_sql = generate_order_by_sql(*window_inputs.order_by, ascending=False)
             if window_inputs.partition_by:
@@ -597,6 +606,8 @@ def func(window_inputs: WindowInputs) -> Expression:
 
     @requires.backend_version((1, 3))
     def diff(self) -> Self:
+        from duckdb import SQLExpression
+
         def func(window_inputs: WindowInputs) -> Expression:
             order_by_sql = generate_order_by_sql(*window_inputs.order_by, ascending=True)
             partition_by_sql = generate_partition_by_sql(*window_inputs.partition_by)
@@ -695,6 +706,7 @@ def fill_null(
             if self._backend_version < (1, 3):  # pragma: no cover
                 msg = f"`fill_null` with `strategy={strategy}` is only available in 'duckdb>=1.3.0'."
                 raise NotImplementedError(msg)
+            from duckdb import SQLExpression
 
             def _fill_with_strategy(window_inputs: WindowInputs) -> Expression:
                 order_by_sql = generate_order_by_sql(
@@ -731,6 +743,8 @@ def func(expr: Expression) -> Expression:
 
     @requires.backend_version((1, 3))
     def is_unique(self) -> Self:
+        from duckdb import SQLExpression
+
         def func(expr: Expression) -> Expression:
             sql = f"count(*) over (partition by {expr})"
             return SQLExpression(sql) == lit(1)  # type: ignore[no-any-return, unused-ignore]
@@ -739,6 +753,8 @@ def func(expr: Expression) -> Expression:
 
     @requires.backend_version((1, 3))
     def rank(self, method: RankMethod, *, descending: bool) -> Self:
+        from duckdb import SQLExpression
+
         if method in {"min", "max", "average"}:
             func = FunctionExpression("rank")
         elif method == "dense":

narwhals/_pandas_like/expr.py

@@ -309,7 +309,8 @@ def func(df: PandasLikeDataFrame) -> Sequence[PandasLikeSeries]:  # noqa: C901,
                 results = [result_frame.get_column(name) for name in aliases]
                 if order_by:
                     for s in results:
-                        s._scatter_in_place(sorting_indices, s)
+                        # `sorting_indices` was initialised in `if order_by` block above.
+                        s._scatter_in_place(sorting_indices, s)  # pyright: ignore[reportPossiblyUnboundVariable]
                     return results
                 if reverse:
                     return [s._gather_slice(slice(None, None, -1)) for s in results]

pyproject.toml

@@ -326,8 +326,10 @@ warn_return_any = false
 pythonPlatform = "All"
 # NOTE (stubs do unsafe `TypeAlias` and `TypeVar` imports)
 # pythonVersion = "3.8"
+reportFunctionMemberAccess = "error"
 reportMissingImports = "none"
 reportMissingModuleSource = "none"
+reportPossiblyUnboundVariable = "error"
 reportPrivateImportUsage = "none"
 reportUnusedExpression = "none"    # handled by (https://docs.astral.sh/ruff/rules/unused-variable/)
 typeCheckingMode = "basic"