anchor.diff:              .single;
           return new SearchSnapshot.fromJson(json);
         } catch (e, st) {
  -        _logger.severe('Unable to load search snapshot: $path', e, st);
  +        _logger.severe(
  +            'Unable to load search snapshot: ${_bucketUri(bucket, path)}',
  +            e,
  +            st);
         }
         return null;
       }
  
positive.code:       try {
          await bucket.delete(name);
        } catch (e, st) {
          _logger.warning('Snapshot delete failed: $name', e, st);
        }
      }
    }
  
negative.code:             .transform(JSON.decoder)
              .single;
        } catch (e, st) {
          _logger.severe(
              'Unable to load popularity data: ${_bucketUri(bucket, path)}',
              e,
              st);
        }
        return null;
      }
  