templates: add support for "in" and "not in" using a lazy left operand (#49958)

tests/test_formdata.py

@@ -1521,6 +1521,20 @@ def test_lazy_conditions(pub, variable_test_data):
     assert condition.evaluate() is True
 
 
+def test_lazy_conditions_in(pub, variable_test_data):
+    condition = Condition({'type': 'django', 'value': 'form_var_foo_foo in "foo, bar, baz"'})
+    assert condition.evaluate() is True
+
+    condition = Condition({'type': 'django', 'value': 'form_var_foo_foo not in "foo, bar, baz"'})
+    assert condition.evaluate() is False
+
+    condition = Condition({'type': 'django', 'value': '"b" in form_var_foo_foo'})
+    assert condition.evaluate() is True
+
+    condition = Condition({'type': 'django', 'value': '"b" not in form_var_foo_foo'})
+    assert condition.evaluate() is False
+
+
 def test_has_role_templatefilter(pub, variable_test_data):
     condition = Condition({'type': 'django', 'value': 'form_user|has_role:"foobar"'})
     assert condition.evaluate() is False

wcs/conditions.py

@@ -16,6 +16,7 @@
 
 from quixote import get_publisher
 from django.template import Context, Template, TemplateSyntaxError
+import django.template.smartif
 from django.utils.encoding import force_text
 
 from .qommon import _, get_logger, force_str
@@ -94,3 +95,21 @@ class Condition(object):
             Template('{%% if %s %%}OK{%% endif %%}' % self.value)
         except (TemplateSyntaxError, OverflowError) as e:
             raise ValidationError(_('syntax error: %s') % force_str(force_text(e)))
+
+
+# add support for "in" and "not in" operators with left operand being a lazy
+# value.
+def lazy_eval(context, x):
+    x = x.eval(context)
+    if hasattr(x, 'get_value'):
+        x = x.get_value()
+    return x
+
+
+django.template.smartif.OPERATORS['in'] = django.template.smartif.infix(
+        django.template.smartif.OPERATORS['in'].lbp,
+        lambda context, x, y: lazy_eval(context, x) in y.eval(context))
+
+django.template.smartif.OPERATORS['not in'] = django.template.smartif.infix(
+        django.template.smartif.OPERATORS['not in'].lbp,
+        lambda context, x, y: lazy_eval(context, x) not in y.eval(context))