forms: remove extraneous empty table rows (#11045)

tests/test_form_pages.py

@@ -841,6 +841,42 @@ def test_form_multi_page_post_conditions(pub):
     resp = resp.forms[0].submit('submit')
     assert 'Check values then click submit.' in resp.body
 
+def test_form_multi_page_table_with_rows(pub):
+    formdef = create_formdef()
+    formdef.fields = [fields.PageField(id='0', label='1st page', type='page'),
+            fields.PageField(id='2', label='2nd page', type='page'),
+            fields.TableRowsField(id='1', label='table', columns=['a', 'b'])
+            ]
+    formdef.store()
+    page = get_app(pub).get('/test/')
+    formdef.data_class().wipe()
+    page = page.form.submit('submit')
+    page.form['f1$element0$col0'] = 'bar1'
+    page.form['f1$element1$col0'] = 'bar2'
+    page.form['f1$element2$col0'] = 'bar3'
+    page.form['f1$element3$col0'] = 'bar4'
+    page.form['f1$element4$col0'] = 'bar5'
+    page = page.form.submit('f1$add_element')
+    assert not  'Check values then click submit.' in page.body
+    page.form['f1$element5$col0'] = 'bar6'
+    page = page.form.submit('f1$add_element')
+    assert not  'Check values then click submit.' in page.body
+    page.form['f1$element6$col0'] = 'bar7'
+    page = page.form.submit('submit')
+    assert 'Check values then click submit.' in page.body
+    page = page.forms[0].submit('previous')
+    page = page.forms[0].submit('submit')
+    assert 'Check values then click submit.' in page.body
+    assert not 'f1$element7$col0' in page.body
+    page = page.forms[0].submit('submit')
+    assert page.status_int == 302
+    page = page.follow()
+    assert 'The form has been recorded' in page.body
+    assert formdef.data_class().count() == 1
+    data_id = formdef.data_class().select()[0].id
+    data = formdef.data_class().get(data_id)
+    assert data.data == {'1': [['bar%s' % x, ''] for x in range(1, 8)]}
+
 def test_form_submit_with_user(pub, emails):
     create_user(pub)
     formdef = create_formdef()

wcs/qommon/form.py

@@ -1604,6 +1604,18 @@ class TableListRowsWidget(WidgetListAsTable):
 
         self.set_value(value)
 
+        # WidgetList.__init__ added as many extra rows as what there is in
+        # name$added_elements, but this is on top of the existing rows,
+        # making it quite an unnecessary number of empty rows.
+        # fixup this so that we don't have more than one empty row.
+        if value:
+            for i, element_name in enumerate(self.element_names[:]):
+                if i < len(value):
+                    continue
+                self.element_names.remove(element_name)
+                self.widgets.remove(self.get_widget(element_name))
+                del self._names[element_name]
+
     def parse(self, request=None):
         WidgetListAsTable.parse(self, request=request)
         if request is None: