tests/form_pages/test_block.py

@@ -715,6 +715,58 @@ def test_block_multi_string_modify_prefill(pub):
     assert resp.form['f3$element2$f123'].value == 'Bye World'  # updated
 
 
+def test_block_string_prefill_and_items(pub):
+    FormDef.wipe()
+    BlockDef.wipe()
+
+    block = BlockDef()
+    block.name = 'foobar'
+    block.fields = [
+        fields.StringField(
+            id='123',
+            required=True,
+            label='Test',
+            prefill={'type': 'string', 'value': '{{ form_var_foo }} World'},
+        ),
+        fields.ItemsField(
+            id='234',
+            required=False,
+            label='Items',
+            items=['Pomme', 'Poire', 'Pêche', 'Abricot'],
+        ),
+    ]
+    block.store()
+
+    formdef = FormDef()
+    formdef.name = 'form title'
+    formdef.fields = [
+        fields.PageField(id='0', label='1st page'),
+        fields.StringField(id='1', label='string', varname='foo'),
+        fields.PageField(id='2', label='2nd page'),
+        fields.BlockField(id='3', label='test', block_slug='foobar', max_items=5),
+    ]
+    formdef.store()
+    formdef.data_class().wipe()
+
+    app = get_app(pub)
+    resp = app.get(formdef.get_url())
+    resp.form['f1'] = 'Hello'
+    resp = resp.form.submit('submit')  # -> 2nd page
+    assert resp.form['f3$element0$f123'].value == 'Hello World'
+    resp = resp.form.submit('f3$add_element')  # add second row
+    assert resp.form['f3$element1$f123'].value == 'Hello World'
+    resp = resp.form.submit('f3$add_element')  # add third row
+    assert resp.form['f3$element2$f123'].value == 'Hello World'
+    resp = resp.form.submit('submit')  # -> validation page
+    resp = resp.form.submit('submit')  # -> end page
+    resp = resp.follow()
+
+    formdata = formdef.data_class().select()[0]
+    assert formdata.data['3']['data'][0]['123'] == 'Hello World'
+    assert formdata.data['3']['data'][1]['123'] == 'Hello World'
+    assert formdata.data['3']['data'][2]['123'] == 'Hello World'
+
+
 def test_workflow_form_block_prefill(pub):
     FormDef.wipe()
     BlockDef.wipe()

wcs/fields/base.py

@@ -974,7 +974,7 @@ class WidgetField(Field):
         )
 
     def check_admin_form(self, form):
-        display_locations = form.get_widget('display_locations').parse()
+        display_locations = form.get_widget('display_locations').parse() or []
         varname = form.get_widget('varname').parse()
         if 'statistics' in display_locations and not varname:
             form.set_error(

wcs/qommon/form.py

@@ -1871,7 +1871,7 @@ class CheckboxesWidget(Widget):
             name = option['name']
             if name in request.form and not request.form[name] in (False, '', 'False'):
                 values.append(option['value'])
-        self.value = values
+        self.value = values or None
         if self.required and not self.value:
             self.set_error(self.REQUIRED_ERROR)
         if self.value and self.min_choices and len(self.value) < self.min_choices: