SOLR-15071: Fix ArrayIndexOutOfBoundsException in contrib/ltr SolrFeatureScorer (#2196)

Author: cpoerschke

solr/CHANGES.txt

@@ -366,6 +366,9 @@ Bug Fixes
 
 * SOLR-15073: Fix ClassCastException in SystemInfoHandler.getSecurityInfo. (Nikolay Ivanov, Christine Poerschke)
 
+* SOLR-15071: Fix ArrayIndexOutOfBoundsException in contrib/ltr SolrFeatureScorer.
+  (Florin Babes, Ovidiu Mihalcea, David Smiley, Christine Poerschke)
+
 Other Changes
 ---------------------
 

solr/contrib/ltr/src/java/org/apache/solr/ltr/feature/Feature.java

@@ -27,7 +27,6 @@
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.QueryVisitor;
 import org.apache.lucene.search.Scorer;
-import org.apache.lucene.search.TwoPhaseIterator;
 import org.apache.lucene.search.Weight;
 import org.apache.lucene.util.Accountable;
 import org.apache.lucene.util.RamUsageEstimator;
@@ -365,10 +364,9 @@ public DocIdSetIterator iterator() {
         return in.iterator();
       }
 
-      @Override
-      public TwoPhaseIterator twoPhaseIterator() {
-        return in.twoPhaseIterator();
-      }
+      // Currently (Q1 2021) we intentionally don't delegate twoPhaseIterator()
+      // because it doesn't always work and we don't yet know why, please see
+      // SOLR-15071 for more details.
 
       @Override
       public int advanceShallow(int target) throws IOException {

solr/contrib/ltr/src/test/org/apache/solr/ltr/feature/TestEdisMaxSolrFeature.java

@@ -21,7 +21,6 @@
 import org.apache.solr.ltr.model.LinearModel;
 import org.junit.After;
 import org.junit.Before;
-import org.junit.Ignore;
 import org.junit.Test;
 
 public class TestEdisMaxSolrFeature extends TestRerankBase {
@@ -75,7 +74,6 @@ public void testEdisMaxSolrFeature() throws Exception {
     assertJQ("/query" + query.toQueryString(), "/response/numFound/==4");
   }
 
-  @Ignore("SOLR-15071")
   @Test
   public void testEdisMaxSolrFeatureCustomMM() throws Exception {
     loadFeature(

solr/contrib/ltr/src/test/org/apache/solr/ltr/feature/TestFeature.java

@@ -30,6 +30,9 @@ public void testFilterFeatureScorerOverridesScorerMethods() {
     for (final Method scorerClassMethod : Scorer.class.getDeclaredMethods()) {
       try {
 
+        // the FilterFeatureScorer may simply inherit Scorer's default implementation
+        if (scorerClassMethod.getName().equals("twoPhaseIterator")) continue;
+
         // the FilterFeatureScorer's implementation does not influence its parent Weight
         if (scorerClassMethod.getName().equals("getWeight")) continue;