From cbf160a4e6c6c13f63f2d0d2dd1adf006fc70d97 Mon Sep 17 00:00:00 2001
From: Julie Tibshirani <julie.tibshirani@elastic.co>
Date: Thu, 16 Aug 2018 17:36:58 -0700
Subject: [PATCH] For filters aggs, make sure that rewrites preserve
 other_bucket. (#32921)

---
 .../bucket/filter/FiltersAggregationBuilder.java   |  5 ++++-
 .../search/aggregations/bucket/FiltersTests.java   | 14 ++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/server/src/main/java/org/elasticsearch/search/aggregations/bucket/filter/FiltersAggregationBuilder.java b/server/src/main/java/org/elasticsearch/search/aggregations/bucket/filter/FiltersAggregationBuilder.java
index e35bf376aae..810126e8512 100644
--- a/server/src/main/java/org/elasticsearch/search/aggregations/bucket/filter/FiltersAggregationBuilder.java
+++ b/server/src/main/java/org/elasticsearch/search/aggregations/bucket/filter/FiltersAggregationBuilder.java
@@ -209,7 +209,10 @@ public class FiltersAggregationBuilder extends AbstractAggregationBuilder<Filter
             }
         }
         if (changed) {
-            return new FiltersAggregationBuilder(getName(), rewrittenFilters, this.keyed);
+            FiltersAggregationBuilder rewritten = new FiltersAggregationBuilder(getName(), rewrittenFilters, this.keyed);
+            rewritten.otherBucket(otherBucket);
+            rewritten.otherBucketKey(otherBucketKey);
+            return rewritten;
         } else {
             return this;
         }
diff --git a/server/src/test/java/org/elasticsearch/search/aggregations/bucket/FiltersTests.java b/server/src/test/java/org/elasticsearch/search/aggregations/bucket/FiltersTests.java
index 327a717f05c..bdfdd4d028f 100644
--- a/server/src/test/java/org/elasticsearch/search/aggregations/bucket/FiltersTests.java
+++ b/server/src/test/java/org/elasticsearch/search/aggregations/bucket/FiltersTests.java
@@ -178,4 +178,18 @@ public class FiltersTests extends BaseAggregationTestCase<FiltersAggregationBuil
         assertSame(rewritten,
             rewritten.rewrite(new QueryRewriteContext(xContentRegistry(), null, null, () -> 0L)));
     }
+
+    public void testRewritePreservesOtherBucket() throws IOException {
+        FiltersAggregationBuilder originalFilters = new FiltersAggregationBuilder("my-agg", new BoolQueryBuilder());
+        originalFilters.otherBucket(randomBoolean());
+        originalFilters.otherBucketKey(randomAlphaOfLength(10));
+
+        AggregationBuilder rewritten = originalFilters.rewrite(new QueryRewriteContext(xContentRegistry(),
+            null, null, () -> 0L));
+        assertThat(rewritten, instanceOf(FiltersAggregationBuilder.class));
+
+        FiltersAggregationBuilder rewrittenFilters = (FiltersAggregationBuilder) rewritten;
+        assertEquals(originalFilters.otherBucket(), rewrittenFilters.otherBucket());
+        assertEquals(originalFilters.otherBucketKey(), rewrittenFilters.otherBucketKey());
+    }
 }