misc: add |is_empty filter (#50402)

tests/test_formdata.py

@@ -1219,6 +1219,12 @@ def test_lazy_formdata_queryset_filter(pub, variable_test_data):
     assert LazyFormData(formdata).objects.pending().count == 7
     assert LazyFormData(formdata).objects.pending().filter_by('foo_foo').apply_filter_value('foo').count == 0
 
+    # test |is_empty
+    tmpl = Template('{{form_objects|pending|is_empty}}')
+    assert tmpl.render(context) == 'False'
+    tmpl = Template('{{form_objects|pending|filter_by:"foo_foo"|filter_value:"foo"|is_empty}}')
+    assert tmpl.render(context) == 'True'
+
     # test |getlist
     tmpl = Template('{% for v in form_objects|order_by:"id"|getlist:"foo_foo" %}{{ v }},{% endfor %}')
     assert tmpl.render(context) == 'bar,bar,bar,bar,bar,bar,bar,foo,foo,foo,foo,'
@@ -1235,6 +1241,12 @@ def test_lazy_formdata_queryset_filter(pub, variable_test_data):
     assert LazyFormData(formdata).objects.order_by('id').getlist('form_var_foo_foo') == [
         'bar', 'bar', 'bar', 'bar', 'bar', 'bar', 'bar', 'foo', 'foo', 'foo', 'foo']
     assert set(LazyFormData(formdata).objects.getlist('unknown')) == set([None])
+    tmpl = Template('{{form_objects|pending|getlist:"foo_foo"|is_empty}}')
+    assert tmpl.render(context) == 'False'
+    tmpl = Template('{{form_objects|filter_by:"foo_foo"|filter_value:"foo"|getlist:"foo_foo"|is_empty}}')
+    assert tmpl.render(context) == 'False'
+    tmpl = Template('{{form_objects|pending|filter_by:"foo_foo"|filter_value:"foo"|getlist:"foo_foo"|is_empty}}')
+    assert tmpl.render(context) == 'True'
 
     # test with cache populated
     for value in [datetime.date(2018, 7, 31).timetuple(), datetime.date(2018, 7, 31), datetime.datetime(2018, 7, 31), '2018-07-31']:

tests/test_templates.py

@@ -1108,3 +1108,16 @@ def test_django_contrib_humanize_filters():
     with override_settings(LANGUAGE_CODE='fr-fr'):
         assert tmpl.render({'foo': 10000}) == '10 000'
         assert tmpl.render({'foo': '10000'}) == '10 000'
+
+
+def test_is_empty():
+    tmpl = Template('{{ foo|is_empty }}')
+    assert tmpl.render({}) == 'True'
+    assert tmpl.render({'foo': ''}) == 'True'
+    assert tmpl.render({'foo': None}) == 'True'
+    assert tmpl.render({'foo': 'foo'}) == 'False'
+    assert tmpl.render({'foo': 42}) == 'False'
+    assert tmpl.render({'foo': []}) == 'True'
+    assert tmpl.render({'foo': ['foo']}) == 'False'
+    assert tmpl.render({'foo': {}}) == 'True'
+    assert tmpl.render({'foo': {'foo': 42}}) == 'False'

wcs/qommon/templatetags/qommon.py

@@ -68,7 +68,7 @@ def get(mapping, key):
 
 @register.filter
 def getlist(mapping, key):
-    if not mapping or not hasattr(mapping, 'getlist'):
+    if mapping is None or not hasattr(mapping, 'getlist'):
         return []
     return mapping.getlist(key)
 
@@ -755,3 +755,13 @@ def phonenumber_fr(value, separator=' '):
 
     # unknown
     return value
+
+
+@register.filter
+def is_empty(value):
+    from wcs.variables import LazyFormDefObjectsManager, LazyList
+    if isinstance(value, (six.string_types, list, dict)):
+        return not value
+    if isinstance(value, (LazyFormDefObjectsManager, LazyList)):
+        return not list(value)
+    return value is None