forms: give prefilling access to form_parent_* variables (#54220)

tests/form_pages/test_all.py

@@ -8632,6 +8632,49 @@ def test_create_formdata_empty_item_ds_with_id_parameter(pub, create_formdata):
             assert pub.loggederror_class.count() == 0
 
 
+def test_create_formdata_locked_prefill_parent(create_formdata):
+    create_formdata['source_formdef'].data_class().wipe()
+    create_formdata['target_formdef'].data_class().wipe()
+
+    target_formdef = create_formdata['target_formdef']
+    target_formdef.fields[0].prefill = {
+        'type': 'string',
+        'value': '{{form_parent_form_var_toto_string}}',
+        'locked': True,
+    }
+    target_formdef.store()
+
+    app = get_app(create_formdata['pub'])
+    resp = app.get('/source-form/')
+    resp.form['f0'] = 'zob'
+    resp.form['f1$file'] = Upload('test.txt', b'foobar', 'text/plain')
+    resp.form['f2'] = '2'
+    resp = resp.form.submit('submit')  # -> validation
+    resp = resp.form.submit('submit')  # -> submission
+    resp = resp.follow()
+    assert create_formdata['target_formdef'].data_class().count() == 0
+    resp = resp.form.submit('button_resubmit')
+    assert create_formdata['target_formdef'].data_class().count() == 1
+    target_formdata = create_formdata['target_formdef'].data_class().select()[0]
+    assert target_formdata.data.get('0') == 'zob'
+    assert target_formdata.status == 'draft'
+
+    resp = resp.follow()
+    resp = resp.follow()
+    assert resp.forms[1]['f0'].value == 'zob'
+    assert resp.forms[1]['f0'].attrs['readonly']
+    # try altering readonly field
+    resp.forms[1]['f0'].value = 'xxx'
+    resp = resp.forms[1].submit('submit')
+    resp = resp.forms[1].submit('previous')
+    assert resp.forms[1]['f0'].value == 'zob'
+    resp = resp.forms[1].submit('submit')
+    resp = resp.forms[1].submit('submit')
+    assert create_formdata['target_formdef'].data_class().count() == 1
+    target_formdata = create_formdata['target_formdef'].data_class().select()[0]
+    assert target_formdata.data['0'] == 'zob'
+
+
 def test_js_libraries(pub):
     create_formdef()
     resp = get_app(pub).get('/test/', status=200)

wcs/forms/root.py

@@ -739,6 +739,16 @@ class FormPage(Directory, FormTemplateMixin):
             formdata.workflow_data = self.edited_data.workflow_data
             return formdata
 
+        if formdata.data.get('is_recalled_draft'):
+            # restore submission context, this is required to get access to form_parent_* variables
+            draft_formdata_id = formdata.data.get('draft_formdata_id')
+            try:
+                draft_formdata = self.formdef.data_class().get(draft_formdata_id)
+            except KeyError:  # it may not exist
+                pass
+            else:
+                formdata.submission_context = draft_formdata.submission_context
+
         if get_request().is_in_backoffice():
             formdata.user_id = None
             draft_formdata_id = formdata.data.get('draft_formdata_id')