Harold, Thanks for the report.
I took a look and it seems the ReqExclScorer requires a scorer to be passed and it is initially invalid until NextDoc() is called. See https://github.com/apache/lucenenet/blob/a3a12967b250e8e7e5f623f0ba7572ec64f479ac/src/Lucene.Net/Search/ReqExclScorer.cs#L115 Other than that I can't tell you much without seeing a code sample that can be executed to determine exactly why the error is happening and whether this is a bug or by design. Thanks, Shad Storhaug (NightOwl888) -----Original Message----- From: Harold Harkema [mailto:[email protected]] Sent: Tuesday, December 19, 2017 5:04 PM To: [email protected] Subject: NullReferenceException in DrillSideways.Search Hi, We have converted our 3.0.3 solution to Lucene 4.8.0-beta00005. Most of it works fine and a lot better/faster! Thanks for the good work! However we have an issue with DrillSideways.Search. Is this a known issue or could it be our code? Or any suggestions where to look or how to troubleshoot this? This is part of the stacktrace. The rest of the stacktrace is only our code. System.NullReferenceException: Object reference not set to an instance of an object. at Lucene.Net.Search.ReqExclScorer.GetCost() in C:\BuildAgent\work\b1b63ca15b99dddb\src\Lucene.Net\Search\ReqExclScorer.cs:line 148 at Lucene.Net.Facet.DrillSidewaysScorer.Score(ICollector collector, Int32 maxDoc) in C:\BuildAgent\work\b1b63ca15b99dddb\src\Lucene.Net.Facet\DrillSidewaysScorer.cs:line 139 at Lucene.Net.Search.IndexSearcher.Search(IList`1 leaves, Weight weight, ICollector collector) in C:\BuildAgent\work\b1b63ca15b99dddb\src\Lucene.Net\Search\IndexSearcher.cs:line 649 at Lucene.Net.Facet.DrillSideways.Search(DrillDownQuery query, ICollector hitCollector) in C:\BuildAgent\work\b1b63ca15b99dddb\src\Lucene.Net.Facet\DrillSideways.cs:line 194 at Lucene.Net.Facet.DrillSideways.Search(ScoreDoc after, DrillDownQuery query, Int32 topN) in C:\BuildAgent\work\b1b63ca15b99dddb\src\Lucene.Net.Facet\DrillSideways.cs:line 249 Harold
