HBASE-29804: NullPointerException in WorkerAssigner.serverAdded during Master Shutdown and Restart

[teamconfx]

Fix for HBASE-29804.

Summary of Changes

WorkerAssigner.java:

• Added null checks in serverAdded() to prevent NPE
• Added stop() method to unregister from ServerManager

SnapshotManager.java

The stop() method is called via mpmHost.stop("server shutting down.") in HMaster.stopServiceThreads(). Added:

if (verifyWorkerAssigner != null) {
  verifyWorkerAssigner.stop();
}

SplitWALManager.java (end of file)

Added new stop() method:

public void stop() {
  splitWorkerAssigner.stop();
}

HMaster.java

Added explicit call before stopProcedureExecutor():

if (this.splitWALManager != null) {
  this.splitWALManager.stop();
}

Call Hierarchy During Shutdown

HMaster.stopServiceThreads()
├── splitWALManager.stop() // HBASE-29804: Added before stopProcedureExecutor
│ └── splitWorkerAssigner.stop() // Unregisters from ServerManager
├── stopProcedureExecutor() // Sets procedureExecutor = null
│ ...
└── mpmHost.stop()
└── SnapshotManager.stop()
└── verifyWorkerAssigner.stop() // HBASE-29804: Unregisters from ServerManager

The null check in serverAdded() is the primary safety mechanism since there's a window between stopProcedureExecutor() and mpmHost.stop() where SnapshotManager's WorkerAssigner is still registered. The stop() calls ensure proper cleanup.

[Apache-HBase]

🎊 +1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 29s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 1s		codespell was not available.
+0 🆗	detsecrets	0m 1s		detect-secrets was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
+1 💚	hbaseanti	0m 0s		Patch does not have any anti-patterns.
			_ master Compile Tests _
+1 💚	mvninstall	3m 29s		master passed
+1 💚	compile	3m 37s		master passed
+1 💚	checkstyle	1m 2s		master passed
+1 💚	spotbugs	1m 41s		master passed
+1 💚	spotless	0m 51s		branch has no errors when running spotless:check.
			_ Patch Compile Tests _
+1 💚	mvninstall	3m 5s		the patch passed
+1 💚	compile	3m 25s		the patch passed
+1 💚	javac	3m 25s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	1m 1s		the patch passed
+1 💚	spotbugs	1m 46s		the patch passed
+1 💚	hadoopcheck	12m 12s		Patch does not cause any errors with Hadoop 3.3.6 3.4.1.
+1 💚	spotless	0m 46s		patch has no errors when running spotless:check.
			_ Other Tests _
+1 💚	asflicense	0m 12s		The patch does not generate ASF License warnings.
		42m 24s

Subsystem	Report/Notes
Docker	ClientAPI=1.43 ServerAPI=1.43 base: https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-7666/1/artifact/yetus-general-check/output/Dockerfile
GITHUB PR	#7666
Optional Tests	dupname asflicense javac spotbugs checkstyle codespell detsecrets compile hadoopcheck hbaseanti spotless
uname	Linux 9a624144d9f8 5.4.0-1103-aws #111~18.04.1-Ubuntu SMP Tue May 23 20:04:10 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/hbase-personality.sh
git revision	master / 7b44627
Default Java	Eclipse Adoptium-17.0.11+9
Max. process+thread count	85 (vs. ulimit of 30000)
modules	C: hbase-server U: hbase-server
Console output	https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-7666/1/console
versions	git=2.34.1 maven=3.9.8 spotbugs=4.7.3
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[Apache-HBase]

💔 -1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 29s		Docker mode activated.
-0 ⚠️	yetus	0m 3s		Unprocessed flag(s): --brief-report-file --spotbugs-strict-precheck --author-ignore-list --blanks-eol-ignore-file --blanks-tabs-ignore-file --quick-hadoopcheck
			_ Prechecks _
			_ master Compile Tests _
+1 💚	mvninstall	3m 22s		master passed
+1 💚	compile	0m 58s		master passed
+1 💚	javadoc	0m 30s		master passed
+1 💚	shadedjars	5m 45s		branch has no errors when building our shaded downstream artifacts.
			_ Patch Compile Tests _
+1 💚	mvninstall	2m 56s		the patch passed
+1 💚	compile	0m 57s		the patch passed
+1 💚	javac	0m 57s		the patch passed
+1 💚	javadoc	0m 29s		the patch passed
+1 💚	shadedjars	5m 40s		patch has no errors when building our shaded downstream artifacts.
			_ Other Tests _
-1 ❌	unit	235m 4s	/patch-unit-hbase-server.txt	hbase-server in the patch failed.
		261m 32s

Subsystem	Report/Notes
Docker	ClientAPI=1.43 ServerAPI=1.43 base: https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-7666/1/artifact/yetus-jdk17-hadoop3-check/output/Dockerfile
GITHUB PR	#7666
Optional Tests	javac javadoc unit compile shadedjars
uname	Linux 22f5bdc7c1c0 5.4.0-1103-aws #111~18.04.1-Ubuntu SMP Tue May 23 20:04:10 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/hbase-personality.sh
git revision	master / 7b44627
Default Java	Eclipse Adoptium-17.0.11+9
Test Results	https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-7666/1/testReport/
Max. process+thread count	4818 (vs. ulimit of 30000)
modules	C: hbase-server U: hbase-server
Console output	https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-7666/1/console
versions	git=2.34.1 maven=3.9.8
Powered by	Apache Yetus 0.15.0 https://yetus.apache.org

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