HADOOP-18821. LdapGroupsMapping crashes with NullPointerException while going up the group hierarchy

[teamconfx]

Description of PR

https://issues.apache.org/jira/browse/HADOOP-18821
This PR provides a fix by checking the groupResults is not Null before it is accessed, similar to what's done in org.apache.hadoop.security.LdapGroupsMapping#lookupGroup

How was this patch tested?

Unit test

For code changes:

• Does the title or this PR starts with the corresponding JIRA issue id (e.g. 'HADOOP-17799. Your PR title ...')?
• Object storage: have the integration tests been executed and the endpoint declared according to the connector-specific documentation?
• If adding new dependencies to the code, are these dependencies licensed in a way that is compatible for inclusion under ASF 2.0?
• If applicable, have you updated the LICENSE, LICENSE-binary, NOTICE-binary files?

[hadoop-yetus]

💔 -1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 45s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 0s		codespell was not available.
+0 🆗	detsecrets	0m 0s		detect-secrets was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
-1 ❌	test4tests	0m 0s		The patch doesn't appear to include any new or modified tests. Please justify why no new tests are needed for this patch. Also please list what manual steps were performed to verify this patch.
			_ trunk Compile Tests _
+1 💚	mvninstall	44m 58s		trunk passed
+1 💚	compile	17m 18s		trunk passed with JDK Ubuntu-11.0.20+8-post-Ubuntu-1ubuntu120.04
+1 💚	compile	16m 6s		trunk passed with JDK Private Build-1.8.0_382-8u382-ga-1~20.04.1-b05
+1 💚	checkstyle	1m 24s		trunk passed
+1 💚	mvnsite	1m 47s		trunk passed
+1 💚	javadoc	1m 24s		trunk passed with JDK Ubuntu-11.0.20+8-post-Ubuntu-1ubuntu120.04
+1 💚	javadoc	0m 59s		trunk passed with JDK Private Build-1.8.0_382-8u382-ga-1~20.04.1-b05
+1 💚	spotbugs	2m 42s		trunk passed
+1 💚	shadedclient	35m 43s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+1 💚	mvninstall	0m 56s		the patch passed
+1 💚	compile	16m 32s		the patch passed with JDK Ubuntu-11.0.20+8-post-Ubuntu-1ubuntu120.04
+1 💚	javac	16m 33s		the patch passed
+1 💚	compile	16m 10s		the patch passed with JDK Private Build-1.8.0_382-8u382-ga-1~20.04.1-b05
+1 💚	javac	16m 10s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	1m 20s		the patch passed
+1 💚	mvnsite	1m 45s		the patch passed
+1 💚	javadoc	1m 18s		the patch passed with JDK Ubuntu-11.0.20+8-post-Ubuntu-1ubuntu120.04
+1 💚	javadoc	0m 59s		the patch passed with JDK Private Build-1.8.0_382-8u382-ga-1~20.04.1-b05
+1 💚	spotbugs	2m 49s		the patch passed
+1 💚	shadedclient	35m 46s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
+1 💚	unit	19m 14s		hadoop-common in the patch passed.
+1 💚	asflicense	1m 11s		The patch does not generate ASF License warnings.
		226m 8s

Subsystem	Report/Notes
Docker	ClientAPI=1.43 ServerAPI=1.43 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-6066/1/artifact/out/Dockerfile
GITHUB PR	#6066
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell detsecrets
uname	Linux c220fdf3fb47 4.15.0-212-generic #223-Ubuntu SMP Tue May 23 13:09:22 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	trunk / c8b6207
Default Java	Private Build-1.8.0_382-8u382-ga-1~20.04.1-b05
Multi-JDK versions	/usr/lib/jvm/java-11-openjdk-amd64:Ubuntu-11.0.20+8-post-Ubuntu-1ubuntu120.04 /usr/lib/jvm/java-8-openjdk-amd64:Private Build-1.8.0_382-8u382-ga-1~20.04.1-b05
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-6066/1/testReport/
Max. process+thread count	2650 (vs. ulimit of 5500)
modules	C: hadoop-common-project/hadoop-common U: hadoop-common-project/hadoop-common
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-6066/1/console
versions	git=2.25.1 maven=3.6.3 spotbugs=4.2.2
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[github-actions]

We're closing this stale PR because it has been open for 100 days with no activity. This isn't a judgement on the merit of the PR in any way. It's just a way of keeping the PR queue manageable.
If you feel like this was a mistake, or you would like to continue working on it, please feel free to re-open it and ask for a committer to remove the stale tag and review again.
Thanks all for your contribution.