From 6d6da7c66175d30bb3edc7c7762c281693ee1880 Mon Sep 17 00:00:00 2001
From: James Baiera <james.baiera@gmail.com>
Date: Wed, 2 May 2018 14:40:57 -0400
Subject: [PATCH] Fix merging logic of Suggester Options (#29514)

Suggester Options have a collate match field that is returned when the prune
option is set to true. These values should be merged together in the query
reduce phase, otherwise good suggestions that result in rare hits in shards with
results that do not arrive first may be incorrectly marked as not matching the
collate query.
---
 .../elasticsearch/search/suggest/Suggest.java |  7 ++++++
 .../search/suggest/SuggestTests.java          | 24 ++++++++++++++++++-
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/server/src/main/java/org/elasticsearch/search/suggest/Suggest.java b/server/src/main/java/org/elasticsearch/search/suggest/Suggest.java
index a54f1193df0..e4099193359 100644
--- a/server/src/main/java/org/elasticsearch/search/suggest/Suggest.java
+++ b/server/src/main/java/org/elasticsearch/search/suggest/Suggest.java
@@ -742,6 +742,13 @@ public class Suggest implements Iterable<Suggest.Suggestion<? extends Entry<? ex
 
                 protected void mergeInto(Option otherOption) {
                     score = Math.max(score, otherOption.score);
+                    if (otherOption.collateMatch != null) {
+                        if (collateMatch == null) {
+                            collateMatch = otherOption.collateMatch;
+                        } else {
+                            collateMatch |= otherOption.collateMatch;
+                        }
+                    }
                 }
 
                 @Override
diff --git a/server/src/test/java/org/elasticsearch/search/suggest/SuggestTests.java b/server/src/test/java/org/elasticsearch/search/suggest/SuggestTests.java
index d54fa0f705f..412dd3c6a20 100644
--- a/server/src/test/java/org/elasticsearch/search/suggest/SuggestTests.java
+++ b/server/src/test/java/org/elasticsearch/search/suggest/SuggestTests.java
@@ -191,5 +191,27 @@ public class SuggestTests extends ESTestCase {
         }
     }
 
-
+    public void testMergingSuggestionOptions() {
+        String suggestedWord = randomAlphaOfLength(10);
+        String secondWord = randomAlphaOfLength(10);
+        Text suggestionText = new Text(suggestedWord + " " + secondWord);
+        Text highlighted = new Text("<em>" + suggestedWord + "</em> " + secondWord);
+        PhraseSuggestion.Entry.Option option1 = new Option(suggestionText, highlighted, 0.7f, false);
+        PhraseSuggestion.Entry.Option option2 = new Option(suggestionText, highlighted, 0.8f, true);
+        PhraseSuggestion.Entry.Option option3 = new Option(suggestionText, highlighted, 0.6f);
+        assertEquals(suggestionText, option1.getText());
+        assertEquals(highlighted, option1.getHighlighted());
+        assertFalse(option1.collateMatch());
+        assertTrue(option1.getScore() > 0.6f);
+        option1.mergeInto(option2);
+        assertEquals(suggestionText, option1.getText());
+        assertEquals(highlighted, option1.getHighlighted());
+        assertTrue(option1.collateMatch());
+        assertTrue(option1.getScore() > 0.7f);
+        option1.mergeInto(option3);
+        assertEquals(suggestionText, option1.getText());
+        assertEquals(highlighted, option1.getHighlighted());
+        assertTrue(option1.getScore() > 0.7f);
+        assertTrue(option1.collateMatch());
+    }
 }