enh: ruff S rule fix (#526)

* flake8-bandit

* rm agg arrow assertions

* not covering

* one more :(

* edit err msg and type

narwhals/_arrow/group_by.py

@@ -72,9 +72,12 @@ def agg_arrow(
         simple_aggregations: dict[str, tuple[str, str]] = {}
         for expr in exprs:
             # e.g. agg(nw.mean('a')) # noqa: ERA001
-            assert expr._depth == 1
-            assert expr._root_names is not None
-            assert expr._output_names is not None
+            if (
+                expr._depth != 1 or expr._root_names is None or expr._output_names is None
+            ):  # pragma: no cover
+                msg = "Safety assertion failed, please report a bug to https://github.com/narwhals-dev/narwhals/issues"
+                raise AssertionError(msg)
+
             function_name = remove_prefix(expr._function_name, "col->")
             function_name = POLARS_TO_ARROW_AGGREGATIONS.get(function_name, function_name)
             for root_name, output_name in zip(expr._root_names, expr._output_names):

narwhals/_expression_parsing.py

@@ -189,8 +189,11 @@ def func(df: CompliantDataFrame) -> list[CompliantSeries]:
                 out.append(plx._create_series_from_scalar(_out, column))  # type: ignore[arg-type]
             else:
                 out.append(_out)
-        if expr._output_names is not None:  # safety check
-            assert [s.name for s in out] == expr._output_names
+        if expr._output_names is not None and (
+            [s.name for s in out] != expr._output_names
+        ):  # pragma: no cover
+            msg = "Safety assertion failed, please report a bug to https://github.com/narwhals-dev/narwhals/issues"
+            raise AssertionError(msg)
         return out
 
     # Try tracking root and output names by combining them from all
@@ -211,9 +214,12 @@ def func(df: CompliantDataFrame) -> list[CompliantSeries]:
             output_names = None
             break
 
-    assert (output_names is None and root_names is None) or (
-        output_names is not None and root_names is not None
-    )  # safety check
+    if not (
+        (output_names is None and root_names is None)
+        or (output_names is not None and root_names is not None)
+    ):  # pragma: no cover
+        msg = "Safety assertion failed, please report a bug to https://github.com/narwhals-dev/narwhals/issues"
+        raise AssertionError(msg)
 
     return plx._create_expr_from_callable(  # type: ignore[return-value]
         func,  # type: ignore[arg-type]

narwhals/_pandas_like/group_by.py

@@ -119,7 +119,10 @@ def agg_pandas(
         for expr in exprs:
             if expr._depth == 0:
                 # e.g. agg(nw.len()) # noqa: ERA001
-                assert expr._output_names is not None
+                if expr._output_names is None:  # pragma: no cover
+                    msg = "Safety assertion failed, please report a bug to https://github.com/narwhals-dev/narwhals/issues"
+                    raise AssertionError(msg)
+
                 function_name = POLARS_TO_PANDAS_AGGREGATIONS.get(
                     expr._function_name, expr._function_name
                 )
@@ -128,9 +131,12 @@ def agg_pandas(
                 continue
 
             # e.g. agg(nw.mean('a')) # noqa: ERA001
-            assert expr._depth == 1
-            assert expr._root_names is not None
-            assert expr._output_names is not None
+            if (
+                expr._depth != 1 or expr._root_names is None or expr._output_names is None
+            ):  # pragma: no cover
+                msg = "Safety assertion failed, please report a bug to https://github.com/narwhals-dev/narwhals/issues"
+                raise AssertionError(msg)
+
             function_name = remove_prefix(expr._function_name, "col->")
             function_name = POLARS_TO_PANDAS_AGGREGATIONS.get(
                 function_name, function_name

pyproject.toml

@@ -62,13 +62,16 @@ lint.ignore = [
   'PLR2004',
   'PTH',
   'RET505',
-  'S',
   'SLF001',
   'TD003',
   'TRY003',  # TODO(Unassigned): enable
   'TRY004'
 ]
 
+[tool.ruff.lint.per-file-ignores]
+"tests/*" = ["S101"]
+"utils/*" = ["S311"]
+
 [tool.ruff.lint.isort]
 force-single-line = true