anchor.diff:      if (analysis == null) {
         final list = await db.lookup([versionKey]);
         final PackageVersionAnalysis pva = list[0];
  -      if (pva == null) return null;
  +      if (pva == null) {
  +        _logger.info(
  +            'PackageVersionAnalysis lookup failed: no entry for $package $version.');
  +        return null;
  +      }
         analysis = pva.latestAnalysis;
         lookupMatchingPanaVersion =
             panaVersion != null && pva.panaVersion != panaVersion;
  
positive.code:     if (version == null) {
        final list = await db.lookup([packageKey]);
        final PackageAnalysis pa = list[0];
        if (pa == null) return null;
        version = pa.latestVersion;
      }
  
  
negative.code:         list.sort((a, b) => -a.timestamp.compareTo(b.timestamp));
          final Analysis entry = list[0];
          return _toData(entry);
        } else {
          _logger.info(
              "Analysis lookup failed for $package $version (panaVersion=$panaVersion)");
        }
      }
  
      // analysis was set
      final Key analysisKey = versionKey.append(Analysis, id: analysis);
      final List list = await db.lookup([analysisKey]);
      final Analysis entry = list[0];
      if (entry == null) {
        _logger.info(
            "Analysis lookup failed for $package $version (id=${analysis ?? ''}).");
        return null;
      }
      return _toData(entry);
    }
  
    AnalysisData _toData(Analysis entry) {
  