anchor.diff:      if (p.likes < 0) {
         yield 'Package "${p.name}" has a `likes` property which is not a non-negative integer.';
       }
  -    for (String? userId in p.uploaders!) {
  -      if (!_userToOauth.containsKey(userId)) {
  -        yield 'Package "${p.name}" has uploader without User: "$userId".';
  -      }
  -      if (_invalidUsers.contains(userId)) {
  -        yield 'Package "${p.name}" has invalid uploader: "$userId".';
  -      }
  +    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
  
positive.code:       if (!_publishers.contains(pm.publisherId)) {
          yield 'PublisherMember "${pm.userId}" references a non-existing `publisherId`: "${pm.publisherId}".';
        }
        if (_deletedUsers.contains(pm.userId)) {
          yield 'PublisherMember "${pm.publisherId}" / "${pm.userId}" references a deleted User.';
        }
        if (!_userToOauth.containsKey(pm.userId)) {
          yield 'PublisherMember "${pm.publisherId}" / "${pm.userId}" references a non-existing User.';
        }
      }
    }
  
negative.code:             ' has a `packageName` property which is not the same as `package`/`id`.';
        }
  
        yield* _checkUserValid(like.userId, entityType: 'Like');
  
        if (await _packageMissing(like.package)) {
          yield 'User "${like.userId}" likes missing package "${like.package}".';
        }
      }
    }
  