Fix permission of problem comments

judge/comments.py

@@ -80,8 +80,10 @@ class CommentedDetailView(TemplateResponseMixin, SingleObjectMixin, View):
         return self.comment_page
 
     def is_comment_locked(self):
-        return (CommentLock.objects.filter(page=self.get_comment_page()).exists() and
-                not self.request.user.has_perm('judge.override_comment_lock'))
+        if self.request.user.has_perm('judge.override_comment_lock'):
+            return False
+        return (CommentLock.objects.filter(page=self.get_comment_page()).exists()
+            or (self.request.in_contest and self.request.participation.contest.use_clarifications))
 
     @method_decorator(login_required)
     def post(self, request, *args, **kwargs):

templates/problem/problem.html

@@ -164,8 +164,11 @@
     {% endif %}
     <div><a href="{{ url('chronological_submissions', problem.code) }}">{{ _('All submissions') }}</a></div>
     <div><a href="{{ url('ranked_submissions', problem.code) }}">{{ _('Best submissions') }}</a></div>
-    <hr>
-    <div><a href="{{ url('problem_comments', problem.code) }}">{{ _('Discuss') }}</a></div>
+    
+    {% if not contest_problem or not contest_problem.contest.use_clarifications %}
+        <hr>
+        <div><a href="{{ url('problem_comments', problem.code) }}">{{ _('Discuss') }}</a></div>
+    {% endif %}
     {% if editorial and editorial.is_public and 
             not (request.user.is_authenticated and request.profile.current_contest) %}
         <div><a href="{{ url('problem_editorial', problem.code) }}">{{ _('Read editorial') }}</a></div>