From b7c7ca8f0946c73a1226855d2e8953069f6387d2 Mon Sep 17 00:00:00 2001
From: Jim Ferenczi <jimczi@apache.org>
Date: Thu, 9 May 2019 14:25:07 +0200
Subject: [PATCH] Fix IAE on cross_fields query introduced in 7.0.1 (#41938)

If the max doc in the index is greater than the minimum total term frequency
among the requested fields we need to adjust max doc to be equal to the min ttf.
This was removed by mistake when fixing #41125.

Closes #41934
---
 .../lucene/queries/BlendedTermQuery.java      |  4 ++-
 .../lucene/queries/BlendedTermQueryTests.java | 30 +++++++++++++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/server/src/main/java/org/apache/lucene/queries/BlendedTermQuery.java b/server/src/main/java/org/apache/lucene/queries/BlendedTermQuery.java
index 1700979c32d..c696d476bbb 100644
--- a/server/src/main/java/org/apache/lucene/queries/BlendedTermQuery.java
+++ b/server/src/main/java/org/apache/lucene/queries/BlendedTermQuery.java
@@ -118,7 +118,9 @@ public abstract class BlendedTermQuery extends Query {
                 // otherwise the statistics don't match
                 minSumTTF = Math.min(minSumTTF, reader.getSumTotalTermFreq(terms[i].field()));
             }
-
+        }
+        if (maxDoc > minSumTTF) {
+            maxDoc = (int)minSumTTF;
         }
         if (max == 0) {
             return; // we are done that term doesn't exist at all
diff --git a/server/src/test/java/org/apache/lucene/queries/BlendedTermQueryTests.java b/server/src/test/java/org/apache/lucene/queries/BlendedTermQueryTests.java
index ce33c247a33..9d05e119cbb 100644
--- a/server/src/test/java/org/apache/lucene/queries/BlendedTermQueryTests.java
+++ b/server/src/test/java/org/apache/lucene/queries/BlendedTermQueryTests.java
@@ -227,4 +227,34 @@ public class BlendedTermQueryTests extends ESTestCase {
         assertThat(extracted.size(), equalTo(terms.size()));
         assertThat(extracted, containsInAnyOrder(terms.toArray(new Term[0])));
     }
+
+    public void testMinTTF() throws IOException {
+        Directory dir = newDirectory();
+        IndexWriter w = new IndexWriter(dir, newIndexWriterConfig(new MockAnalyzer(random())));
+        FieldType ft = new FieldType(TextField.TYPE_NOT_STORED);
+        ft.freeze();
+
+        for (int i = 0; i < 10; i++) {
+            Document d = new Document();
+            d.add(new TextField("id", Integer.toString(i), Field.Store.YES));
+            d.add(new Field("dense", "foo foo foo", ft));
+            if (i % 10 == 0) {
+                d.add(new Field("sparse", "foo", ft));
+            }
+            w.addDocument(d);
+        }
+        w.commit();
+        DirectoryReader reader = DirectoryReader.open(w);
+        IndexSearcher searcher = setSimilarity(newSearcher(reader));
+        {
+            String[] fields = new String[]{"dense", "sparse"};
+            Query query = BlendedTermQuery.dismaxBlendedQuery(toTerms(fields, "foo"), 0.1f);
+            TopDocs search = searcher.search(query, 10);
+            ScoreDoc[] scoreDocs = search.scoreDocs;
+            assertEquals(Integer.toString(0), reader.document(scoreDocs[0].doc).getField("id").stringValue());
+        }
+        reader.close();
+        w.close();
+        dir.close();
+    }
 }