forms: don't display errors after "add row" is clicked (#43551)

tests/test_form_pages.py

@@ -3294,6 +3294,24 @@ def test_form_table_rows_field_and_prefill(pub, emails):
     resp = get_app(pub).get('/test/')
 
 
+def test_form_table_rows_add_row(pub):
+    formdef = create_formdef()
+    formdef.fields = [
+        fields.StringField(id='1', label='string', require=True),
+        fields.TableRowsField(id='0', label='table', type='tablerows', columns=['a', 'b'], required=True),
+    ]
+    formdef.store()
+    formdef.data_class().wipe()
+
+    resp = get_app(pub).get('/test/')
+    assert resp.form['f0$added_elements'].value == '5'
+    resp = resp.form.submit('f0$add_element')
+    assert resp.form['f0$added_elements'].value == '6'
+    assert 'There were errors processing the form' not in resp
+    resp = resp.form.submit('submit')
+    assert 'There were errors processing the form' in resp
+
+
 def test_formdata_attachment_download(pub):
     create_user(pub)
     wf = Workflow(name='status')

wcs/forms/root.py

@@ -292,7 +292,7 @@ class FormPage(Directory, FormTemplateMixin):
                   'current_page_no': current_position,
                 })
 
-    def page(self, page, page_change=True, page_error_messages=None):
+    def page(self, page, page_change=True, page_error_messages=None, submit_button=None):
         displayed_fields = []
 
         session = get_session()
@@ -302,6 +302,10 @@ class FormPage(Directory, FormTemplateMixin):
             self.feed_current_data(magictoken)
 
         form = self.create_form(page, displayed_fields)
+        if submit_button is True:
+            # submit_button at True means a non-submitting button has been
+            # clicked; details in [ADD_ROW_BUTTON].
+            form.clear_errors()
         if page_error_messages:
             form.add_global_errors(page_error_messages)
         if getattr(session, 'ajax_form_token', None):
@@ -735,7 +739,7 @@ class FormPage(Directory, FormTemplateMixin):
                             return self.validating(data)
                     else:
                         page_no = 0
-                    return self.page(self.pages[page_no], True)
+                    return self.page(self.pages[page_no], page_change=True)
             self.feed_current_data(None)
             if not self.pages:
                 raise errors.TraversalError()
@@ -854,10 +858,11 @@ class FormPage(Directory, FormTemplateMixin):
             # form.get_submit() returns the name of the clicked button, and
             # it will return True if the form has been submitted, but not
             # by clicking on a submit widget; for example if an "add row"
-            # button is clicked.
+            # button is clicked. [ADD_ROW_BUTTON]
             if form.has_errors() or form.get_submit() is True:
                 return self.page(page, page_change=False,
-                        page_error_messages=page_error_messages)
+                        page_error_messages=page_error_messages,
+                        submit_button=form.get_submit())
 
             form_data = session.get_by_magictoken(magictoken, {})
             with get_publisher().substitutions.temporary_feed(