BUG: StringArray * bools (#62706)

Author: jbrockmendel

doc/source/whatsnew/v3.0.0.rst

@@ -1013,6 +1013,7 @@ Strings
 ^^^^^^^
 - Bug in :meth:`Series.str.zfill` raising ``AttributeError`` for :class:`ArrowDtype` (:issue:`61485`)
 - Bug in :meth:`Series.value_counts` would not respect ``sort=False`` for series having ``string`` dtype (:issue:`55224`)
+- Bug in multiplication with a :class:`StringDtype` incorrectly allowing multiplying by bools; explicitly cast to integers instead (:issue:`62595`)
 
 Interval
 ^^^^^^^^

pandas/core/arrays/string_.py

@@ -1113,6 +1113,16 @@ def _cmp_method(self, other, op):
                 other = np.asarray(other)
             other = other[valid]
 
+        other_dtype = getattr(other, "dtype", None)
+        if op.__name__.strip("_") in ["mul", "rmul"] and (
+            lib.is_bool(other) or lib.is_np_dtype(other_dtype, "b")
+        ):
+            # GH#62595
+            raise TypeError(
+                "Cannot multiply StringArray by bools. "
+                "Explicitly cast to integers instead."
+            )
+
         if op.__name__ in ops.ARITHMETIC_BINOPS:
             result = np.empty_like(self._ndarray, dtype="object")
             result[mask] = self.dtype.na_value

pandas/tests/arithmetic/test_string.py

@@ -112,3 +112,25 @@ def test_pyarrow_numpy_string_invalid():
 
     with pytest.raises(TypeError, match="Invalid comparison"):
         ser > ser4
+
+
+def test_mul_bool_invalid(any_string_dtype):
+    # GH#62595
+    dtype = any_string_dtype
+    ser = Series(["a", "b", "c"], dtype=dtype)
+
+    if dtype == object:
+        pytest.skip("This is not expect to raise")
+    elif dtype.storage == "python":
+        msg = "Cannot multiply StringArray by bools. Explicitly cast to integers"
+    else:
+        msg = "Can only string multiply by an integer"
+
+    with pytest.raises(TypeError, match=msg):
+        False * ser
+    with pytest.raises(TypeError, match=msg):
+        ser * True
+    with pytest.raises(TypeError, match=msg):
+        ser * np.array([True, False, True], dtype=bool)
+    with pytest.raises(TypeError, match=msg):
+        np.array([True, False, True], dtype=bool) * ser