Avoid testing iterable truth values in BoxList construction

AUTHORS.rst

@@ -5,6 +5,8 @@ reporting, all input is greatly appreciated!
 
 Code contributions:
 
+- fhgffy
+
 - Alexandre Decan (AlexandreDecan)
 - dhilipsiva (dhilipsiva)
 - MAA (FooBarQuaxx)

CHANGES.rst

@@ -1,6 +1,11 @@
 Changelog
 =========
 
+Unreleased
+----------
+
+* Fix BoxList construction from iterable inputs with false or ambiguous truth values.
+
 Version 7.4.1
 -------------
 

box/box_list.py

@@ -53,7 +53,8 @@ def __init__(self, iterable: Iterable | None = None, box_class: type[box.Box] =
         self.box_options = box_options
         self.box_options["box_class"] = box_class
         self.box_org_ref = iterable
-        if iterable:
+        # 2026-10-10: Iteration does not require a truth value.
+        if iterable is not None:
             for x in iterable:
                 self.append(x)
         self.box_org_ref = None

test/test_box_list.py

@@ -50,6 +50,22 @@ def test_box_list(self):
         assert isinstance(new_list[1], BoxList)
         assert not isinstance(new_list.to_list(), BoxList)
 
+    @pytest.mark.parametrize("falsey", [False, True])
+    def test_box_list_does_not_require_iterable_truth_value(self, falsey):
+        # 2026-10-10: Iterable inputs can be falsey or have no boolean value.
+        class Rows:
+            def __iter__(self):
+                return iter([{"value": 1}])
+
+            def __bool__(self):
+                if falsey:
+                    return False
+                raise ValueError("ambiguous truth value")
+
+        result = BoxList(Rows())
+        assert len(result) == 1
+        assert result[0].value == 1
+
     def test_frozen_list(self):
         bl = BoxList([5, 4, 3], frozen_box=True)
         with pytest.raises(BoxError):