(kafka) branch 4.2 updated: MINOR: Ensure proper visibility of attribute accesses across threads (#21014)

[dajac]

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dajac pushed a commit to branch 4.2
in repository https://gitbox.apache.org/repos/asf/kafka.git


The following commit(s) were added to refs/heads/4.2 by this push:
     new 358dc278fb0 MINOR: Ensure proper visibility of attribute accesses 
across threads (#21014)
358dc278fb0 is described below

commit 358dc278fb0f43435646baa7da16d38606ff2ce5
Author: David Jacot <david.ja...@gmail.com>
AuthorDate: Fri Nov 28 15:56:06 2025 +0100

    MINOR: Ensure proper visibility of attribute accesses across threads 
(#21014)
    
    I found those two cases while working in this area. In both cases, they
    are read by multiple threads so they must either be volatile or
    acquiring the appropriate lock. Using volatile is fine here.
    
    Reviewers: Lianet Magrans <lmagr...@confluent.io>
---
 .../org/apache/kafka/coordinator/common/runtime/CoordinatorRuntime.java | 2 +-
 .../org/apache/kafka/coordinator/group/GroupCoordinatorService.java     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git 
a/coordinator-common/src/main/java/org/apache/kafka/coordinator/common/runtime/CoordinatorRuntime.java
 
b/coordinator-common/src/main/java/org/apache/kafka/coordinator/common/runtime/CoordinatorRuntime.java
index 9d82e983c3e..1d3fb49ad30 100644
--- 
a/coordinator-common/src/main/java/org/apache/kafka/coordinator/common/runtime/CoordinatorRuntime.java
+++ 
b/coordinator-common/src/main/java/org/apache/kafka/coordinator/common/runtime/CoordinatorRuntime.java
@@ -578,7 +578,7 @@ public class CoordinatorRuntime<S extends 
CoordinatorShard<U>, U> implements Aut
         /**
          * The current state.
          */
-        CoordinatorState state;
+        volatile CoordinatorState state;
 
         /**
          * The current epoch of the coordinator. This represents
diff --git 
a/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupCoordinatorService.java
 
b/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupCoordinatorService.java
index 2817eba1798..7e96c126086 100644
--- 
a/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupCoordinatorService.java
+++ 
b/group-coordinator/src/main/java/org/apache/kafka/coordinator/group/GroupCoordinatorService.java
@@ -345,7 +345,7 @@ public class GroupCoordinatorService implements 
GroupCoordinator {
      * The metadata image to extract topic id to names map.
      * This is initialised when the {@link 
GroupCoordinator#onNewMetadataImage(CoordinatorMetadataImage, 
CoordinatorMetadataDelta)} is called
      */
-    private CoordinatorMetadataImage metadataImage = null;
+    private volatile CoordinatorMetadataImage metadataImage = null;
 
     /**
      *