From e0cbf52d1be0c1e19012a1da66a6196241e59c04 Mon Sep 17 00:00:00 2001
From: PJ Fanning <pjfanning@users.noreply.github.com>
Date: Thu, 19 Sep 2024 14:44:53 +0100
Subject: [PATCH] ThreadPoolConfigCopyAdvice often sets null prereqs

---
 .../pekko/instrumentations/DispatcherInstrumentation.scala | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/instrumentation/kamon-pekko/src/main/scala/kamon/instrumentation/pekko/instrumentations/DispatcherInstrumentation.scala b/instrumentation/kamon-pekko/src/main/scala/kamon/instrumentation/pekko/instrumentations/DispatcherInstrumentation.scala
index b2c3a7454..ee8da0bd9 100644
--- a/instrumentation/kamon-pekko/src/main/scala/kamon/instrumentation/pekko/instrumentations/DispatcherInstrumentation.scala
+++ b/instrumentation/kamon-pekko/src/main/scala/kamon/instrumentation/pekko/instrumentations/DispatcherInstrumentation.scala
@@ -167,9 +167,10 @@ object ThreadPoolConfigCopyAdvice {
 
   @Advice.OnMethodExit
   @static def exit(@Advice.This original: Any, @Advice.Return copy: Any): Unit = {
-    copy.asInstanceOf[HasDispatcherPrerequisites].setDispatcherPrerequisites(
-      original.asInstanceOf[HasDispatcherPrerequisites].dispatcherPrerequisites
-    )
+    val prereqs = original.asInstanceOf[HasDispatcherPrerequisites].dispatcherPrerequisites
+    if (prereqs != null) {
+      copy.asInstanceOf[HasDispatcherPrerequisites].setDispatcherPrerequisites(prereqs)
+    }
     copy.asInstanceOf[HasDispatcherName].setDispatcherName(original.asInstanceOf[HasDispatcherName].dispatcherName)
   }
 }