From 0f9b3127030f596c8c187e22b1badd88e4bf9662 Mon Sep 17 00:00:00 2001
From: Jared Harley <jared@jaredharley.com>
Date: Mon, 4 Aug 2025 22:22:54 -0600
Subject: [PATCH] KAFKA-19576 Fix typo in state-change log filename after
 rotate (#20269)

The `state-change.log` file is being incorrectly rotated to
`stage-change.log.[date]`. This change fixes the typo to have the log
file correctly rotated to `state-change.log.[date]`

_No functional changes._

Reviewers: Mickael Maison <mickael.maison@gmail.com>, Christo Lolov
 <lolovc@amazon.com>, Luke Chen <showuon@gmail.com>, Ken Huang
 <s7133700@gmail.com>, TengYao Chi <kitingiao@gmail.com>, Chia-Ping Tsai
 <chia7712@gmail.com>
---
 config/log4j2.yaml |  2 +-
 docs/upgrade.html  | 20 +++++++++++++++-----
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/config/log4j2.yaml b/config/log4j2.yaml
index 7ee6f001e18..891a5c71cde 100644
--- a/config/log4j2.yaml
+++ b/config/log4j2.yaml
@@ -44,7 +44,7 @@ Configuration:
       # State Change appender
       - name: StateChangeAppender
         fileName: "${sys:kafka.logs.dir}/state-change.log"
-        filePattern: "${sys:kafka.logs.dir}/stage-change.log.%d{yyyy-MM-dd-HH}"
+        filePattern: "${sys:kafka.logs.dir}/state-change.log.%d{yyyy-MM-dd-HH}"
         PatternLayout:
           pattern: "${logPattern}"
         TimeBasedTriggeringPolicy:
diff --git a/docs/upgrade.html b/docs/upgrade.html
index 4e24c149320..cb6f4cdc666 100644
--- a/docs/upgrade.html
+++ b/docs/upgrade.html
@@ -19,9 +19,9 @@
 
 <script id="upgrade-template" type="text/x-handlebars-template">
 
-<h4><a id="upgrade_4_0_0" href="#upgrade_4_0_0">Upgrading to 4.0.0</a></h4>
+<h4><a id="upgrade_4_0_1" href="#upgrade_4_0_1">Upgrading to 4.0.1</a></h4>
 
-<h5><a id="upgrade_clients_4_0_0" href="#upgrade_clients_4_0_0">Upgrading Clients to 4.0.0</a></h5>
+<h5><a id="upgrade_clients_4_0_1" href="#upgrade_clients_4_0_1">Upgrading Clients to 4.0.1</a></h5>
 
 <p><b>For a rolling upgrade:</b></p>
 
@@ -32,7 +32,7 @@
         or <a href="https://cwiki.apache.org/confluence/x/y4kgF">KIP-1124</a>.</li>
 </ol>
 
-<h5><a id="upgrade_servers_4_0_0" href="#upgrade_servers_4_0_0">Upgrading Servers to 4.0.0 from any version 3.3.x through 3.9.x</a></h5>
+<h5><a id="upgrade_servers_4_0_1" href="#upgrade_servers_4_0_1">Upgrading Servers to 4.0.1 from any version 3.3.x through 3.9.x</a></h5>
 
 <p>Note: Apache Kafka 4.0 only supports KRaft mode - ZooKeeper mode has been removed. As such, <b>broker upgrades to 4.0.0 (and higher) require KRaft mode and
     the software and metadata versions must be at least 3.3.x</b> (the first version when KRaft mode was deemed production ready). For clusters in KRaft mode
@@ -56,7 +56,13 @@
         has a boolean parameter that indicates if there are metadata changes (i.e. <code>IBP_4_0_IV1(23, "4.0", "IV1", true)</code> means this version has metadata changes).
         Given your current and target versions, a downgrade is only possible if there are no metadata changes in the versions between.</li>
 </ol>
-
+    <h5><a id="upgrade_servers_401_notable" href="#upgrade_servers_401_notable">Notable changes in 4.0.1</a></h5>
+    <ul>
+        <li>
+            The filename for rotated <code>state-change.log</code> files has been updated from <code>stage-change.log.[date]</code> to <code>state-change.log.[date]</code> in the log4j2.yaml configuration file.
+            See <a href="https://issues.apache.org/jira/browse/KAFKA-19576">KAFKA-19576</a> for details.
+        </li>
+    </ul>
     <h5><a id="upgrade_servers_400_notable" href="#upgrade_servers_400_notable">Notable changes in 4.0.0</a></h5>
     <ul>
         <li>
@@ -68,7 +74,7 @@
         </li>
         <li>
             Apache Kafka 4.0 only supports KRaft mode - ZooKeeper mode has been removed. About version upgrade,
-            check <a href="/{{version}}/documentation.html#upgrade_4_0_0">Upgrading to 4.0.0 from any version 3.3.x through 3.9.x</a> for more info.
+            check <a href="/{{version}}/documentation.html#upgrade_4_0_1">Upgrading to 4.0.1 from any version 3.3.x through 3.9.x</a> for more info.
         </li>
         <li>
             Apache Kafka 4.0 ships with a brand-new group coordinator implementation (See <a href="https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=217387038#KIP848:TheNextGenerationoftheConsumerRebalanceProtocol-GroupCoordinator">here</a>).
@@ -411,6 +417,10 @@
                     <li> See <a href="https://cwiki.apache.org/confluence/display/KAFKA/KIP-890%3A+Transactions+Server-Side+Defense">KIP-890</a> and
                     <a href="https://cwiki.apache.org/confluence/display/KAFKA/KIP-1050%3A+Consistent+error+handling+for+Transactions">KIP-1050</a> for more details </li>
                 </ul>
+                <li>
+                    The filename for rotated <code>state-change.log</code> files incorrectly rotates to <code>stage-change.log.[date]</code> (changing state to stage). This issue is corrected in 4.0.1.
+                    See <a href="https://issues.apache.org/jira/browse/KAFKA-19576">KAFKA-19576</a> for details.
+                </li>
             </ul>
         </li>
     </ul>