HDFS-17803 : Compute correct checksum type when file is empty

[chayanikabhandary]

Description of PR

When the file is empty or the file size is 0, the checksum returned is always MD5MD5CRC type even when the selected checksum type is COMPOSITE_CRC.

This is misleading and can create confusion while debugging.

How was this patch tested?

Unit tests added

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	14m 59s		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 appears to include 1 new or modified test files.
			_ trunk Compile Tests _
+1 💚	mvninstall	36m 42s		trunk passed
+1 💚	compile	0m 58s		trunk passed with JDK Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04
+1 💚	compile	0m 52s		trunk passed with JDK Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
+1 💚	checkstyle	0m 34s		trunk passed
+1 💚	mvnsite	0m 56s		trunk passed
+1 💚	javadoc	0m 49s		trunk passed with JDK Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04
+1 💚	javadoc	0m 43s		trunk passed with JDK Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
+1 💚	spotbugs	2m 29s		trunk passed
+1 💚	shadedclient	36m 37s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+1 💚	mvninstall	0m 44s		the patch passed
+1 💚	compile	0m 48s		the patch passed with JDK Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04
+1 💚	javac	0m 48s		the patch passed
+1 💚	compile	0m 42s		the patch passed with JDK Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
+1 💚	javac	0m 42s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
-0 ⚠️	checkstyle	0m 21s	/results-checkstyle-hadoop-hdfs-project_hadoop-hdfs-client.txt	hadoop-hdfs-project/hadoop-hdfs-client: The patch generated 40 new + 0 unchanged - 0 fixed = 40 total (was 0)
+1 💚	mvnsite	0m 44s		the patch passed
+1 💚	javadoc	0m 36s		the patch passed with JDK Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04
+1 💚	javadoc	0m 33s		the patch passed with JDK Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
+1 💚	spotbugs	2m 24s		the patch passed
+1 💚	shadedclient	36m 38s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
+1 💚	unit	2m 48s		hadoop-hdfs-client in the patch passed.
-1 ❌	asflicense	0m 37s	/results-asflicense.txt	The patch generated 1 ASF License warnings.
		142m 42s

Subsystem	Report/Notes
Docker	ClientAPI=1.51 ServerAPI=1.51 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-7764/1/artifact/out/Dockerfile
GITHUB PR	#7764
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell detsecrets
uname	Linux ffa53ee2a00d 5.15.0-139-generic #149-Ubuntu SMP Fri Apr 11 22:06:13 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
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git revision	trunk / 0bee7e1
Default Java	Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
Multi-JDK versions	/usr/lib/jvm/java-11-openjdk-amd64:Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04 /usr/lib/jvm/java-8-openjdk-amd64:Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-7764/1/testReport/
Max. process+thread count	545 (vs. ulimit of 5500)
modules	C: hadoop-hdfs-project/hadoop-hdfs-client U: hadoop-hdfs-project/hadoop-hdfs-client
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-7764/1/console
versions	git=2.25.1 maven=3.6.3 spotbugs=4.2.2
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[hadoop-yetus]

🎊 +1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 34s		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 💚	test4tests	0m 0s		The patch appears to include 1 new or modified test files.
			_ trunk Compile Tests _
+1 💚	mvninstall	40m 24s		trunk passed
+1 💚	compile	1m 2s		trunk passed with JDK Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04
+1 💚	compile	0m 52s		trunk passed with JDK Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
+1 💚	checkstyle	0m 34s		trunk passed
+1 💚	mvnsite	0m 55s		trunk passed
+1 💚	javadoc	0m 48s		trunk passed with JDK Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04
+1 💚	javadoc	0m 40s		trunk passed with JDK Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
+1 💚	spotbugs	2m 34s		trunk passed
+1 💚	shadedclient	39m 38s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+1 💚	mvninstall	0m 45s		the patch passed
+1 💚	compile	0m 52s		the patch passed with JDK Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04
+1 💚	javac	0m 52s		the patch passed
+1 💚	compile	0m 44s		the patch passed with JDK Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
+1 💚	javac	0m 44s		the patch passed
+1 💚	blanks	0m 1s		The patch has no blanks issues.
-0 ⚠️	checkstyle	0m 21s	/results-checkstyle-hadoop-hdfs-project_hadoop-hdfs-client.txt	hadoop-hdfs-project/hadoop-hdfs-client: The patch generated 40 new + 0 unchanged - 0 fixed = 40 total (was 0)
+1 💚	mvnsite	0m 45s		the patch passed
+1 💚	javadoc	0m 38s		the patch passed with JDK Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04
+1 💚	javadoc	0m 32s		the patch passed with JDK Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
+1 💚	spotbugs	2m 35s		the patch passed
+1 💚	shadedclient	37m 35s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
+1 💚	unit	2m 50s		hadoop-hdfs-client in the patch passed.
+1 💚	asflicense	0m 37s		The patch does not generate ASF License warnings.
		136m 0s

Subsystem	Report/Notes
Docker	ClientAPI=1.51 ServerAPI=1.51 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-7764/2/artifact/out/Dockerfile
GITHUB PR	#7764
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell detsecrets
uname	Linux 250f96da6d10 5.15.0-139-generic #149-Ubuntu SMP Fri Apr 11 22:06:13 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	trunk / 1c94a94
Default Java	Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
Multi-JDK versions	/usr/lib/jvm/java-11-openjdk-amd64:Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04 /usr/lib/jvm/java-8-openjdk-amd64:Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-7764/2/testReport/
Max. process+thread count	560 (vs. ulimit of 5500)
modules	C: hadoop-hdfs-project/hadoop-hdfs-client U: hadoop-hdfs-project/hadoop-hdfs-client
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-7764/2/console
versions	git=2.25.1 maven=3.6.3 spotbugs=4.2.2
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[chayanikabhandary]

Hey, can I please get a review on this one?

[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.