From 858e814816b2aaf49c003a4a5b1283637fa877a5 Mon Sep 17 00:00:00 2001
From: David Turner <david.turner@elastic.co>
Date: Thu, 13 Mar 2025 09:43:38 +0000
Subject: [PATCH] Fix stack trace in `ActionListener#assertOnce` (#124672)

In #112380 we changed this `assert` to yield a `String` on failure
rather than the original `ElasticsearchException`, which means we don't
see the original completion's stack trace any more. This commit
reinstates the lost stack trace.
---
 .../main/java/org/elasticsearch/action/ActionListener.java    | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/server/src/main/java/org/elasticsearch/action/ActionListener.java b/server/src/main/java/org/elasticsearch/action/ActionListener.java
index a158669d936fe..5b577eebcf6b0 100644
--- a/server/src/main/java/org/elasticsearch/action/ActionListener.java
+++ b/server/src/main/java/org/elasticsearch/action/ActionListener.java
@@ -390,7 +390,9 @@ static <Response> ActionListener<Response> assertOnce(ActionListener<Response> d
 
                 private void assertFirstRun() {
                     var previousRun = firstCompletion.compareAndExchange(null, new ElasticsearchException("executed already"));
-                    assert previousRun == null : "[" + delegate + "] " + previousRun; // reports the stack traces of both completions
+                    assert previousRun == null
+                        // reports the stack traces of both completions
+                        : new AssertionError("[" + delegate + "]", previousRun);
                 }
 
                 @Override