[1.11.x] Fixed #28058 -- Restored empty BoundFields evaluating to True.

Regression in b52c73008a

Backport of c09bf8d767 from master

django/forms/boundfield.py

@@ -57,6 +57,13 @@ class BoundField(object):
             for widget in self.field.widget.subwidgets(self.html_name, self.value(), attrs=attrs)
         )
 
+    def __bool__(self):
+        # BoundField evaluates to True even if it doesn't have subwidgets.
+        return True
+
+    def __nonzero__(self):      # Python 2 compatibility
+        return type(self).__bool__(self)
+
     def __iter__(self):
         return iter(self.subwidgets)
 

docs/releases/1.11.1.txt

@@ -24,3 +24,6 @@ Bugfixes
 
 * Fixed empty POST data table appearing instead of "No POST data" in HTML debug
   page (:ticket:`28079`).
+
+* Restored ``BoundField``\s without any ``choices`` evaluating to ``True``
+  (:ticket:`28058`).

tests/forms_tests/tests/test_forms.py

@@ -745,6 +745,13 @@ Java</label></li>
             [str(bf[1]), str(bf[2]), str(bf[3])],
         )
 
+    def test_boundfield_bool(self):
+        """BoundField without any choices (subwidgets) evaluates to True."""
+        class TestForm(Form):
+            name = ChoiceField(choices=[])
+
+        self.assertIs(bool(TestForm()['name']), True)
+
     def test_forms_with_multiple_choice(self):
         # MultipleChoiceField is a special case, as its data is required to be a list:
         class SongForm(Form):