define __bool__ for Series and DataFrame to be NoReturn

Author: Dr-Irv

pandas-stubs/core/frame.pyi

@@ -14,6 +14,7 @@ from typing import (
     Any,
     ClassVar,
     Literal,
+    NoReturn,
     overload,
 )
 
@@ -2478,6 +2479,7 @@ class DataFrame(NDFrame, OpsMixin, _GetItemHack):
     ) -> Self: ...
     def __truediv__(self, other: float | DataFrame | Series | Sequence) -> Self: ...
     def __rtruediv__(self, other: float | DataFrame | Series | Sequence) -> Self: ...
+    def __bool__(self) -> NoReturn: ...
 
 class _PandasNamedTuple(tuple[Any, ...]):
     def __getattr__(self, field: str) -> Scalar: ...

pandas-stubs/core/series.pyi

@@ -18,6 +18,7 @@ from typing import (
     ClassVar,
     Generic,
     Literal,
+    NoReturn,
     overload,
 )
 
@@ -2152,6 +2153,7 @@ class Series(IndexOpsMixin[S1], NDFrame):
         level: Level | None = ...,
         drop_level: _bool = ...,
     ) -> Self: ...
+    def __bool__(self) -> NoReturn: ...
 
 class TimestampSeries(Series[Timestamp]):
     @property

tests/test_frame.py

@@ -3781,3 +3781,16 @@ def test_frame_index_timestamp() -> None:
     df2 = pd.DataFrame({"x": s})
     check(assert_type(df2.loc[dt1, "x"], Scalar), np.integer)
     check(assert_type(df2.loc[[dt1], "x"], pd.Series), pd.Series, np.integer)
+
+
+def test_frame_bool_fails() -> None:
+    df = pd.DataFrame({"a": [1, 2, 3], "b": [4, 5, 6]})
+
+    try:
+        # We want the type checker to tell us the next line is invalid
+        # mypy doesn't seem to figure that out, but pyright does
+        if df == "foo":  # pyright: ignore[reportGeneralTypeIssues]
+            # Next line is unreachable.
+            s = df["a"]
+    except ValueError:
+        pass

tests/test_series.py

@@ -3505,3 +3505,16 @@ def test_series_index_timestamp() -> None:
     s = pd.Series([1, 2], index=[dt1, dt2])
     check(assert_type(s[dt1], int), np.integer)
     check(assert_type(s.loc[[dt1]], "pd.Series[int]"), pd.Series, np.integer)
+
+
+def test_series_bool_fails() -> None:
+    s = pd.Series([1, 2, 3])
+
+    try:
+        # We want the type checker to tell us the next line is invalid
+        # mypy doesn't seem to figure that out, but pyright does
+        if s == "foo":  # pyright: ignore[reportGeneralTypeIssues]
+            # Next line is unreachable.
+            a = s[0]
+    except ValueError:
+        pass