anchor.diff:        final userId = _oauthToUser[oauthUserId];
         if (userId == null) {
           yield 'OAuthUserID "$oauthUserId" has no User.';
  -      }
  +        continue;
  +      }
  +      // make sure we have the latest userId -> oauthUserId mapping
  +      await _userExists(userId);
  +      // check mapping
         final pointer = _userToOauth[userId];
         if (pointer == null) {
           yield 'User "$userId" is mapped from OAuthUserID "$oauthUserId", but does not have it set.';
  
positive.code:             ' has a `packageName` property which is not the same as `package`/`id`.';
        }
  
        final userId = like.userId;
        if (!_userToOauth.keys.contains(userId)) {
          yield 'Like entity with nonexisting user "$userId".';
        }
        if (_deletedUsers.contains(userId)) {
          yield 'Like entity with deleted user "$userId".';
        }
  
        if (await _packageMissing(like.package)) {
          yield 'User "$userId" likes missing package "${like.package}".';
        }
      }
    }
  
negative.code:     if (p.likes < 0) {
        yield 'Package "${p.name}" has a `likes` property which is not a non-negative integer.';
      }
      for (final userId in p.uploaders!) {
        yield* _checkUserValid(
          userId,
          entityType: 'Package',
          entityId: p.name,
        );
      }
      if (p.deletedVersions != null) {
        // make sure we store valid versions here
  