misc: fix |count filter for None values (#53924)

tests/test_formdata.py

@@ -2565,6 +2565,10 @@ def test_lazy_formdata_count_as_len_filter(pub):
         tmpl = Template('{{ form_var_value|count }}')
         assert tmpl.render(context) == '4'
 
+    tmpl = Template('{{ form_var_value|count }}')
+    assert tmpl.render({}) == '0'
+    assert tmpl.render({'form_var_value': None}) == '0'
+
 
 def test_rounding_and_abs_conditions_django(pub, variable_test_data):
     for true_condition_value in (

wcs/qommon/templatetags/qommon.py

@@ -687,6 +687,8 @@ def filter_value(queryset, value):
 def count(queryset):
     if hasattr(queryset, 'get_value'):
         queryset = queryset.get_value()  # unlazy
+    if queryset is None:
+        return 0
     return len(queryset)