diff --git a/lucene/facet/src/java/org/apache/lucene/facet/search/DrillSidewaysQuery.java b/lucene/facet/src/java/org/apache/lucene/facet/search/DrillSidewaysQuery.java
index afa0906808c..cbc74a22f35 100644
--- a/lucene/facet/src/java/org/apache/lucene/facet/search/DrillSidewaysQuery.java
+++ b/lucene/facet/src/java/org/apache/lucene/facet/search/DrillSidewaysQuery.java
@@ -122,11 +122,11 @@ class DrillSidewaysQuery extends Query {
             }
             lastField = field;
           }
+          dims[dim].docsEnums = new DocsEnum[drillDownTerms[dim].length];
           if (termsEnum == null) {
             nullCount++;
             continue;
           }
-          dims[dim].docsEnums = new DocsEnum[drillDownTerms[dim].length];
           for(int i=0;i<drillDownTerms[dim].length;i++) {
             if (termsEnum.seekExact(drillDownTerms[dim][i].bytes(), false)) {
               DocsEnum docsEnum = termsEnum.docs(null, null);
@@ -138,7 +138,7 @@ class DrillSidewaysQuery extends Query {
           }
         }
 
-        if (nullCount > 1) {
+        if (nullCount > 1 || (nullCount == 1 && dims.length == 1)) {
           return null;
         }
 
diff --git a/lucene/facet/src/java/org/apache/lucene/facet/search/DrillSidewaysScorer.java b/lucene/facet/src/java/org/apache/lucene/facet/search/DrillSidewaysScorer.java
index c3f2eecd2ed..42f53905935 100644
--- a/lucene/facet/src/java/org/apache/lucene/facet/search/DrillSidewaysScorer.java
+++ b/lucene/facet/src/java/org/apache/lucene/facet/search/DrillSidewaysScorer.java
@@ -80,11 +80,9 @@ class DrillSidewaysScorer extends Scorer {
     // Position all scorers to their first matching doc:
     baseScorer.nextDoc();
     for(DocsEnumsAndFreq dim : dims) {
-      if (dim.docsEnums != null) {
-        for (DocsEnum docsEnum : dim.docsEnums) {
-          if (docsEnum != null) {
-            docsEnum.nextDoc();
-          }
+      for (DocsEnum docsEnum : dim.docsEnums) {
+        if (docsEnum != null) {
+          docsEnum.nextDoc();
         }
       }
     }
@@ -97,11 +95,9 @@ class DrillSidewaysScorer extends Scorer {
     for(int dim=0;dim<numDims;dim++) {
       docsEnums[dim] = dims[dim].docsEnums;
       sidewaysCollectors[dim] = dims[dim].sidewaysCollector;
-      if (dims[dim].docsEnums != null) {
-        for (DocsEnum de : dims[dim].docsEnums) {
-          if (de != null) {
-            drillDownCost += de.cost();
-          }
+      for (DocsEnum de : dims[dim].docsEnums) {
+        if (de != null) {
+          drillDownCost += de.cost();
         }
       }
     }
diff --git a/lucene/facet/src/test/org/apache/lucene/facet/search/TestDrillSideways.java b/lucene/facet/src/test/org/apache/lucene/facet/search/TestDrillSideways.java
index 846d911b120..9772f90d44d 100644
--- a/lucene/facet/src/test/org/apache/lucene/facet/search/TestDrillSideways.java
+++ b/lucene/facet/src/test/org/apache/lucene/facet/search/TestDrillSideways.java
@@ -28,11 +28,15 @@ import java.util.Map;
 import java.util.Set;
 
 import org.apache.lucene.analysis.MockAnalyzer;
+import org.apache.lucene.codecs.Codec;
+import org.apache.lucene.codecs.DocValuesFormat;
+import org.apache.lucene.codecs.perfield.PerFieldDocValuesFormat;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.StringField;
 import org.apache.lucene.facet.FacetTestCase;
 import org.apache.lucene.facet.FacetTestUtils;
+import org.apache.lucene.facet.codecs.facet42.Facet42DocValuesFormat;
 import org.apache.lucene.facet.index.FacetFields;
 import org.apache.lucene.facet.params.FacetIndexingParams;
 import org.apache.lucene.facet.params.FacetSearchParams;
@@ -58,8 +62,8 @@ import org.apache.lucene.search.Query;
 import org.apache.lucene.search.ScoreDoc;
 import org.apache.lucene.search.Scorer;
 import org.apache.lucene.search.Sort;
-import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.SortField.Type;
+import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.TermQuery;
 import org.apache.lucene.search.TopDocs;
 import org.apache.lucene.store.Directory;
@@ -429,6 +433,16 @@ public class TestDrillSideways extends FacetTestCase {
 
     boolean canUseDV = defaultCodecSupportsSortedSet();
 
+    // TestRuleSetupAndRestoreClassEnv can sometimes
+    // randomly pick the non-general Facet42DocValuesFormat:
+    DocValuesFormat dvf = Codec.getDefault().docValuesFormat();
+    if (dvf instanceof PerFieldDocValuesFormat) {
+      dvf = ((PerFieldDocValuesFormat) dvf).getDocValuesFormatForField("$facets");
+    }
+    if (dvf instanceof Facet42DocValuesFormat) {
+      canUseDV = false;
+    }
+
     while (aChance == 0.0) {
       aChance = random().nextDouble();
     }
@@ -1175,6 +1189,5 @@ public class TestDrillSideways extends FacetTestCase {
     
     IOUtils.close(searcher.getIndexReader(), taxoReader, dir, taxoDir);
   }
-  
 }