Split EditView.post into form_valid and form_invalid methods

wagtail/admin/views/pages/edit.py

@@ -173,12 +173,15 @@ class EditView(TemplateResponseMixin, ContextMixin, View):
             self.request.POST, self.request.FILES, instance=self.page, parent_page=self.parent
         )
 
-        is_valid = self.form.is_valid() and not self.page_perms.page_locked()
+        self.is_cancelling_workflow = bool(self.request.POST.get('action-cancel-workflow')) and self.workflow_state and self.workflow_state.user_can_cancel(self.request.user)
 
-        is_cancelling_workflow = bool(self.request.POST.get('action-cancel-workflow')) and self.workflow_state and self.workflow_state.user_can_cancel(self.request.user)
+        if self.form.is_valid() and not self.page_perms.page_locked():
+            return self.form_valid(self.form)
+        else:
+            return self.form_invalid(self.form)
 
-        if is_valid:
-            if is_cancelling_workflow:
+    def form_valid(self, form):
+        if self.is_cancelling_workflow:
             self.workflow_state.cancel(user=self.request.user)
 
         self.page = self.form.save(commit=False)
@@ -336,7 +339,7 @@ class EditView(TemplateResponseMixin, ContextMixin, View):
                 )
             ])
 
-            elif is_cancelling_workflow:
+        elif self.is_cancelling_workflow:
             self.add_cancel_workflow_confirmation_message()
 
         elif is_restarting_workflow:
@@ -396,9 +399,10 @@ class EditView(TemplateResponseMixin, ContextMixin, View):
                 # Ensure the 'next' url is passed through again if present
                 target_url += '?next=%s' % urlquote(self.next_url)
             return redirect(target_url)
-        else:
+
+    def form_invalid(self, form):
         # even if the page is locked due to not having permissions, the original submitter can still cancel the workflow
-            if is_cancelling_workflow:
+        if self.is_cancelling_workflow:
             self.workflow_state.cancel(user=self.request.user)
             self.add_cancel_workflow_confirmation_message()