crash on profile for anon users

app/models.py

@@ -383,7 +383,7 @@ class User(UserMixin, db.Model):
         if self.is_authenticated:
             return self.id
         else:
-            return None
+            return 0
 
     def display_name(self):
         if self.deleted is False:

app/user/routes.py

@@ -44,7 +44,7 @@ def show_profile(user):
     posts = Post.query.filter_by(user_id=user.id).order_by(desc(Post.posted_at)).paginate(page=post_page, per_page=50, error_out=False)
     moderates = Community.query.filter_by(banned=False).join(CommunityMember).filter(CommunityMember.user_id == user.id)\
         .filter(or_(CommunityMember.is_moderator, CommunityMember.is_owner))
-    if user.id == current_user.id or current_user.is_admin():
+    if current_user.is_authenticated and (user.id == current_user.get_id() or current_user.is_admin()):
         upvoted = Post.query.join(PostVote, PostVote.post_id == Post.id).filter(PostVote.effect > 0, PostVote.user_id == user.id).order_by(desc(PostVote.created_at)).limit(10).all()
     else:
         upvoted = []

app/utils.py

@@ -553,7 +553,7 @@ def user_filters_replies(user_id):
 
 @cache.memoize(timeout=300)
 def moderating_communities(user_id):
-    if user_id is None:
+    if user_id is None or user_id == 0:
         return []
     return Community.query.join(CommunityMember, Community.id == CommunityMember.community_id).\
         filter(Community.banned == False).\
@@ -563,7 +563,7 @@ def moderating_communities(user_id):
 
 @cache.memoize(timeout=300)
 def joined_communities(user_id):
-    if user_id is None:
+    if user_id is None or user_id == 0:
         return []
     return Community.query.join(CommunityMember, Community.id == CommunityMember.community_id).\
         filter(Community.banned == False). \