[FIX] website_forum: don't allow to post an empty question

Instead to post the empty question, now we redirect the end user to the question page with a warning.

This commit closes #12962

addons/website_forum/controllers/main.py

@@ -317,8 +317,11 @@ class WebsiteForum(http.Controller):
                  '/forum/<model("forum.forum"):forum>/<model("forum.post"):post_parent>/reply'],
                 type='http', auth="user", methods=['POST'], website=True)
     def post_create(self, forum, post_parent=None, post_type=None, **post):
-        if post_type == 'question' and not post.get('post_name', '').strip():
+        if post_type == 'question' and not post.get('post_name', ''):
             return request.website.render('website.http_error', {'status_code': _('Bad Request'), 'status_message': _('Title should not be empty.')})
+        if post.get('content', '') == '<p><br></p>':
+            return werkzeug.utils.redirect("/forum/%s/question/%s?nocontent=1" % (slug(forum), post_parent and slug(post_parent)))
+
         post_tag_ids = forum._tag_to_write_vals(post.get('post_tags', ''))
         new_question = request.env['forum.post'].create({
             'forum_id': forum.id,

addons/website_forum/views/website_forum.xml

@@ -690,6 +690,9 @@
         - no need to answer the same question twice. Also, please <b>don't forget to vote</b>
         - it really helps to select the best questions and answers!
     </p>
+    <t t-if="request.params.get('nocontent')">
+        <p class='alert alert-danger' role='alert'>You cannot post an empty answer</p>
+    </t>
     <form t-attf-action="/forum/#{ slug(forum) }/#{slug(question)}/reply" method="post" class="js_website_submit_form" role="form">
         <input type="hidden" name="csrf_token" t-att-value="request.csrf_token()"/>
         <input type="hidden" name="karma" t-attf-value="#{user.karma}" id="karma"/>