[lucene-solr] branch master updated: LUCENE-9661: Fix deadlock in TermsEnum.EMPTY

[na...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

namgyu pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/lucene-solr.git


The following commit(s) were added to refs/heads/master by this push:
     new eb24e95  LUCENE-9661: Fix deadlock in TermsEnum.EMPTY
eb24e95 is described below

commit eb24e95731b9f865b95b821c1745264fdc58119d
Author: Namgyu Kim <na...@apache.org>
AuthorDate: Sat Jan 16 06:49:23 2021 +0900

    LUCENE-9661: Fix deadlock in TermsEnum.EMPTY
---
 lucene/CHANGES.txt                                        |  3 +++
 .../core/src/java/org/apache/lucene/index/TermsEnum.java  | 15 +++++++++++++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/lucene/CHANGES.txt b/lucene/CHANGES.txt
index dfb4efa..7affde9 100644
--- a/lucene/CHANGES.txt
+++ b/lucene/CHANGES.txt
@@ -298,6 +298,9 @@ Bug Fixes
 * LUCENE-9642: When encoding triangles in ShapeField, make sure generated triangles are CCW by rotating 
   triangle points before checking triangle orientation. (Ignacio Vera)  
 
+* LUCENE-9661: Fix deadlock in TermsEnum.EMPTY that occurs when trying to initialize TermsEnum and BaseTermsEnum
+  at the same time (Namgyu Kim)
+
 Other
 ---------------------
 
diff --git a/lucene/core/src/java/org/apache/lucene/index/TermsEnum.java b/lucene/core/src/java/org/apache/lucene/index/TermsEnum.java
index 0f03c94..de0234b 100644
--- a/lucene/core/src/java/org/apache/lucene/index/TermsEnum.java
+++ b/lucene/core/src/java/org/apache/lucene/index/TermsEnum.java
@@ -180,7 +180,10 @@ public abstract class TermsEnum implements BytesRefIterator {
    * of unused Attributes does not matter.
    */
   public static final TermsEnum EMPTY =
-      new BaseTermsEnum() {
+      new TermsEnum() {
+
+        private AttributeSource atts = null;
+
         @Override
         public SeekStatus seekCeil(BytesRef term) {
           return SeekStatus.END;
@@ -226,7 +229,15 @@ public abstract class TermsEnum implements BytesRefIterator {
 
         @Override // make it synchronized here, to prevent double lazy init
         public synchronized AttributeSource attributes() {
-          return super.attributes();
+          if (atts == null) {
+            atts = new AttributeSource();
+          }
+          return atts;
+        }
+
+        @Override
+        public boolean seekExact(BytesRef text) throws IOException {
+          return seekCeil(text) == SeekStatus.FOUND;
         }
 
         @Override