tests/backoffice_pages/test_form_inspect.py

@@ -74,6 +74,7 @@ def test_inspect_page(pub, local_user):
         fields.ItemField(id='3', label='3rd field', type='item', data_source=datasource, varname='foo'),
         fields.FileField(id='4', label='file field', type='file', varname='file'),
         fields.BlockField(id='5', label='Block Data', varname='blockdata', type='block:foobar', max_items=3),
+        fields.StringField(id='6', label='Empty', varname='empty', type='string'),
     ]
     formdef.workflow_roles = {'_receiver': 1}
     formdef.store()
@@ -109,6 +110,7 @@ def test_inspect_page(pub, local_user):
             ],
             'schema': {},  # not important here
         },
+        '6': None,
         '0_display': 'plop poulpe',
     }
     formdata.jump_status('new')
@@ -186,6 +188,11 @@ def test_inspect_page(pub, local_user):
         pq('[title="form_var_blockdata_1_string"]').children('a').attr('href')
         == 'http://example.net/backoffice/forms/blocks/%s/1/' % block.id
     )
+    assert pq('[title="form_var_empty"]').children('a').attr('title') == 'Empty'
+    assert (
+        pq('[title="form_var_empty"]').children('a').attr('href')
+        == 'http://example.net/backoffice/forms/%s/fields/6/' % formdef.id
+    )
 
     # don't show «unusable» variables
     assert 'form_f1' not in resp.text

tests/test_formdata.py

@@ -28,7 +28,7 @@ from wcs.qommon.substitution import CompatibilityNamesDict
 from wcs.qommon.template import Template
 from wcs.qommon.upload_storage import PicklableUpload
 from wcs.sql_criterias import FtsMatch
-from wcs.variables import LazyFormData
+from wcs.variables import LazyFormData, NoneFieldVar
 from wcs.wf.create_formdata import JournalAssignationErrorPart
 from wcs.wf.register_comment import JournalEvolutionPart
 from wcs.wf.wscall import JournalWsCallErrorPart
@@ -211,13 +211,13 @@ def test_file_field(pub, formdef):
 
     formdata.data = {'0': None}
     substvars = formdata.get_substitution_variables()
-    assert substvars['form_var_foo'] is None
+    assert isinstance(substvars['form_var_foo'], NoneFieldVar)
     assert substvars['form_var_foo_raw'] is None
     assert substvars['form_var_foo_url'] is None
 
     formdata.data = {}
     substvars = formdata.get_substitution_variables()
-    assert substvars['form_var_foo'] is None
+    assert isinstance(substvars['form_var_foo'], NoneFieldVar)
     assert substvars['form_var_foo_raw'] is None
     assert substvars['form_var_foo_url'] is None
 
@@ -2035,7 +2035,10 @@ def test_lazy_variables_missing(pub, variable_test_data):
     pub.substitutions.feed(formdata)
     for mode in (None, 'lazy'):
         context = pub.substitutions.get_context_variables(mode=mode)
-        assert context['form_var_foo_foo_baz_baz'] is None
+        if mode == 'lazy':
+            assert isinstance(context['form_var_foo_foo_baz_baz'], NoneFieldVar)
+        else:
+            assert context['form_var_foo_foo_baz_baz'] is None
         assert context['form_var_foo_foo'] == 'bar'
         with pytest.raises(KeyError):
             assert context['form_var_foo_foo_xxx'] == 'bar'
@@ -2119,7 +2122,10 @@ def test_lazy_map_variable(pub, variable_test_data):
         pub.substitutions.reset()
         pub.substitutions.feed(formdef)
         with pub.substitutions.temporary_feed(formdata, force_mode=mode):
-            assert WorkflowStatusItem.compute('=form_var_map', raises=True) is None
+            if mode == 'lazy':
+                assert isinstance(WorkflowStatusItem.compute('=form_var_map', raises=True), NoneFieldVar)
+            else:
+                assert WorkflowStatusItem.compute('=form_var_map', raises=True) is None
             assert (
                 WorkflowStatusItem.compute('{{ form_var_map|distance:"1;2"|floatformat }}', raises=True) == ''
             )

wcs/backoffice/management.py

@@ -64,7 +64,7 @@ from wcs.sql_criterias import (
     StrictNotEqual,
     get_field_id,
 )
-from wcs.variables import LazyFieldVar, LazyList
+from wcs.variables import LazyFieldVar, LazyList, NoneFieldVar
 from wcs.workflows import WorkflowStatusItem, item_classes, template_on_formdata
 
 from ..qommon import _, audit, errors, ezt, force_str, get_cfg, misc, ngettext, ods, pgettext_lazy, template
@@ -3712,6 +3712,8 @@ class FormBackOfficeStatusPage(FormStatusPage):
                         r += htmltext(' <a title="%s" href="%s"></a>' % (v._field.label, field_url))
                 r += htmltext('</code>')
                 r += htmltext('  <div class="value"><span>%s</span>') % v
+                if isinstance(v, NoneFieldVar):
+                    r += htmltext(' <span class="type">(%s)</span>') % _('no value')
             elif isinstance(v, (types.FunctionType, types.MethodType)):
                 continue
             elif k.endswith('form_parent') and isinstance(v, CompatibilityNamesDict) and ('form' in v):

wcs/qommon/templatetags/qommon.py

@@ -544,9 +544,9 @@ def add(term1, term2):
     '''replace the "add" native django filter'''
 
     # consider None content as the empty string
-    if term1 is None:
+    if unlazy(term1) is None:
         term1 = ''
-    if term2 is None:
+    if unlazy(term2) is None:
         term2 = ''
 
     # return available number if the other term is the empty string

wcs/variables.py

@@ -1033,7 +1033,7 @@ class LazyFormDataVar:
         # let boolean pass through, to get None handled as False
         if field.type != 'bool':
             if self._data.get(field.id) is None:
-                return None
+                return NoneFieldVar(**self.get_field_kwargs(field))
 
             if str(field.id) not in self._data:
                 raise KeyError(key)
@@ -1150,6 +1150,11 @@ class LazyFieldVar:
         raise AssertionError('lazy cannot be pickled')
 
 
+class NoneFieldVar(LazyFieldVar):
+    def get_value(self):
+        return None
+
+
 class LazyFieldVarComplex(LazyFieldVar):
     def has_live_data_source(self):
         real_data_source = self._field.get_real_data_source()