SOLR-18181: ValueSourceAugmenter NPE when rows exceed 1000 and scores requested (#4314)

Fixed an NPE caused by queries using ValueSourceAugmenter and querying for > 1000 rows with score. Moved to overriding non-deprecated transform method and correctly referencing DocIterationInfo for score.

Author: mlbiscoc

changelog/unreleased/SOLR-18181-ValueSourceAugmenter-npe.yml

@@ -0,0 +1,7 @@
+title: Fix NPE in ValueSourceAugmenter when rows exceed prefetch limit with scores requested
+type: fixed
+authors:
+  - name: Matthew Biscocho
+links:
+  - name: SOLR-18181
+    url: https://issues.apache.org/jira/browse/SOLR-18181

solr/core/src/java/org/apache/solr/response/transform/ValueSourceAugmenter.java

@@ -30,6 +30,7 @@
 import org.apache.solr.common.SolrDocument;
 import org.apache.solr.common.SolrException;
 import org.apache.solr.response.ResultContext;
+import org.apache.solr.search.DocIterationInfo;
 import org.apache.solr.search.QParser;
 import org.apache.solr.search.SolrIndexSearcher;
 
@@ -142,7 +143,7 @@ public float score() throws IOException {
   IntObjectHashMap<Object> cachedValuesById;
 
   @Override
-  public void transform(SolrDocument doc, int docid) {
+  public void transform(SolrDocument doc, int docid, DocIterationInfo docIterationInfo) {
     Object cacheValue = (cachedValuesById != null) ? cachedValuesById.get(docid) : null;
     if (cacheValue != null) {
       setValue(doc, cacheValue != NULL_SENTINEL ? cacheValue : null);
@@ -153,8 +154,8 @@ public void transform(SolrDocument doc, int docid) {
         LeafReaderContext rcontext = readerContexts.get(idx);
         int localId = docid - rcontext.docBase;
 
-        if (context.wantsScores()) {
-          fcontext.put("scorer", new ScoreAndDoc(localId, (float) doc.get("score")));
+        if (context.wantsScores() && docIterationInfo != null) {
+          fcontext.put("scorer", new ScoreAndDoc(localId, docIterationInfo.score()));
         }
 
         FunctionValues values = valueSource.getValues(fcontext, rcontext);
@@ -168,6 +169,11 @@ public void transform(SolrDocument doc, int docid) {
     }
   }
 
+  @Override
+  public void transform(SolrDocument doc, int docid) {
+    transform(doc, docid, null);
+  }
+
   private abstract static class MutableScorable extends Scorable {
 
     int docBase;

solr/core/src/test/org/apache/solr/response/transform/TestValueSourceAugmenterPrefetchLimit.java

@@ -0,0 +1,71 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.solr.response.transform;
+
+import org.apache.solr.SolrTestCaseJ4;
+import org.junit.BeforeClass;
+
+public class TestValueSourceAugmenterPrefetchLimit extends SolrTestCaseJ4 {
+
+  private static final int MAX_PREFETCH_SIZE = 1000;
+
+  @BeforeClass
+  public static void beforeTests() throws Exception {
+    initCore("solrconfig.xml", "schema.xml");
+
+    // Index enough documents to exceed the prefetch limit
+    final int numDocs = MAX_PREFETCH_SIZE + 10;
+    for (int i = 0; i < numDocs; i++) {
+      assertU(adoc("id", Integer.toString(i)));
+    }
+    assertU(commit());
+  }
+
+  public void testWithScoreBelowPrefetchLimit() {
+    assertQ(
+        "fl=foo:field(id),score with rows within prefetch limit",
+        req(
+            "q", "*:*",
+            "fl", "foo:field(id),score",
+            "rows", String.valueOf(MAX_PREFETCH_SIZE)),
+        "//result[@numFound='" + (MAX_PREFETCH_SIZE + 10) + "']",
+        "//result/doc/float[@name='score']");
+  }
+
+  public void testWithScoreAbovePrefetchLimit() {
+    assertQ(
+        "fl=foo:field(id),score with rows exceeding prefetch limit",
+        req(
+            "q", "*:*",
+            "fl", "foo:field(id),score",
+            "rows", String.valueOf(MAX_PREFETCH_SIZE + 10)),
+        "//result[@numFound='" + (MAX_PREFETCH_SIZE + 10) + "']",
+        "//result/doc/float[@name='score']");
+  }
+
+  public void testWithScoreAbovePrefetchLimitUsingPreFetchDocsParam() {
+    assertQ(
+        "fl=foo:field(id),score with custom preFetchDocs",
+        req(
+            "q", "*:*",
+            "fl", "foo:field(id),score",
+            "rows", String.valueOf(MAX_PREFETCH_SIZE + 10),
+            "preFetchDocs", "2000"), // Set to 2000
+        "//result[@numFound='" + (MAX_PREFETCH_SIZE + 10) + "']",
+        "//result/doc/float[@name='score']");
+  }
+}