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https://issues.apache.org/jira/browse/MRESOLVER-153?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17254913#comment-17254913
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Michael Osipov commented on MRESOLVER-153:
------------------------------------------
I do not fully agree that the tracking file manager requires synchronization.
It is required IF the default sync context is used which does not synchronize
at all. The tracking file manager is always called within a synchronized block.
Re-adding it by default would lead to the same non-sense I have described
before. If am wrong with my analysis, please explain.
What I did previously is that I left the synchronized tracking file manager
intact, but had a non-sync bundled with the Redis sync context to solve this.
Should we go that route again?
> resolver-status.properties file is corrupted due to concurrent writes
> ---------------------------------------------------------------------
>
> Key: MRESOLVER-153
> URL: https://issues.apache.org/jira/browse/MRESOLVER-153
> Project: Maven Resolver
> Issue Type: Bug
> Components: Resolver
> Affects Versions: 1.6.1
> Environment: OSX 11.1 on adoptopenjdk-11.0.8+10
> Reporter: Guy Brand
> Assignee: Michael Osipov
> Priority: Major
> Attachments: screenshot-1.png
>
>
> In our integration tests which run with Maven {{4.0.0-alpha-1-SNAPSHOT}}
> after [this
> commit|https://github.com/apache/maven/commit/7c7de41562a8d83635e8fa21c3a3340298b508a1],
> we face the following error:
> {code:java}
> [main] [INFO]
> ------------------------------------------------------------------------
> [main] [INFO] BUILD FAILURE
> [main] [INFO]
> ------------------------------------------------------------------------
> [main] [INFO] Total time: 0.243 s
> [main] [INFO] Finished at: 2020-12-23T13:48:59+01:00
> [main] [INFO]
> ------------------------------------------------------------------------
> [main] [ERROR] Malformed \uxxxx encoding.
> java.lang.IllegalArgumentException: Malformed \uxxxx encoding.
> at java.util.Properties.loadConvert (Properties.java:675)
> at java.util.Properties.load0 (Properties.java:451)
> at java.util.Properties.load (Properties.java:404)
> at org.eclipse.aether.internal.impl.TrackingFileManager.read
> (TrackingFileManager.java:56)
> at org.eclipse.aether.internal.impl.DefaultUpdateCheckManager.read
> (DefaultUpdateCheckManager.java:511)
> at org.eclipse.aether.internal.impl.DefaultUpdateCheckManager.checkMetadata
> (DefaultUpdateCheckManager.java:250)
> at org.eclipse.aether.internal.impl.DefaultMetadataResolver.resolve
> (DefaultMetadataResolver.java:302)
> at org.eclipse.aether.internal.impl.DefaultMetadataResolver.resolveMetadata
> (DefaultMetadataResolver.java:181)
> at org.eclipse.aether.internal.impl.DefaultRepositorySystem.resolveMetadata
> (DefaultRepositorySystem.java:277)
> at
> org.apache.maven.plugin.version.internal.DefaultPluginVersionResolver.resolveFromRepository
> (DefaultPluginVersionResolver.java:134)
> at
> org.apache.maven.plugin.version.internal.DefaultPluginVersionResolver.resolve
> (DefaultPluginVersionResolver.java:97)
> at
> org.apache.maven.lifecycle.internal.LifecyclePluginResolver.resolveMissingPluginVersions
> (LifecyclePluginResolver.java:67)
> at
> org.apache.maven.lifecycle.internal.DefaultLifecycleTaskSegmentCalculator.calculateTaskSegments
> (DefaultLifecycleTaskSegmentCalculator.java:104)
> at
> org.apache.maven.lifecycle.internal.DefaultLifecycleTaskSegmentCalculator.calculateTaskSegments
> (DefaultLifecycleTaskSegmentCalculator.java:86)
> at org.apache.maven.lifecycle.internal.LifecycleStarter.execute
> (LifecycleStarter.java:92)
> at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:321)
> at org.apache.maven.DefaultMaven.doExecute (DefaultMaven.java:206)
> at org.apache.maven.DefaultMaven.execute (DefaultMaven.java:119)
> at org.apache.maven.cli.MavenCli.execute (MavenCli.java:982)
> at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:296)
> at org.apache.maven.cli.MavenCli.main (MavenCli.java:200)
> at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
> at jdk.internal.reflect.NativeMethodAccessorImpl.invoke
> (NativeMethodAccessorImpl.java:62)
> at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke
> (DelegatingMethodAccessorImpl.java:43)
> at java.lang.reflect.Method.invoke (Method.java:566)
> at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced
> (Launcher.java:282)
> at org.codehaus.plexus.classworlds.launcher.Launcher.launch
> (Launcher.java:225)
> at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode
> (Launcher.java:406)
> at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:347)
> {code}
> It's not consistently failing and OSX based CI agents fail more often than
> Linux or Windows ones. After some investigations we saw that as part of
> https://issues.apache.org/jira/browse/MRESOLVER-132 the synchronization has
> been removed on the {{TrackingFileManager}}
> ([https://github.com/apache/maven-resolver/pull/67]). This now leads to
> concurrent writes on the {{resolver-status.properties}} file in our tests and
> causes the error during the {{Properties#load()}} method wich then throws the
> above error. See this screenshot on how these files look like (cannot add the
> text here as {{null}} characters aren't shown):
> !screenshot-1.png!
> When enabling debug log we also see that the {{DefaultMetadataResolver}}
> threads try to write concurrently to this file:
> {code:java}
> [DefaultMetadataResolver-0-0] [INFO] Downloading from custom-repo2:
> https://repo.maven.apache.org/maven2/mng-xxxx-concurrent-writes-to-resolver-status-file/plugin/maven-metadata.xml
> [DefaultMetadataResolver-0-2] [INFO] Downloading from central-proxy:
> https://repo.maven.apache.org/maven2/mng-xxxx-concurrent-writes-to-resolver-status-file/plugin/maven-metadata.xml
> [DefaultMetadataResolver-0-1] [INFO] Downloading from custom-repo:
> https://repository.apache.org/snapshots/mng-xxxx-concurrent-writes-to-resolver-status-file/plugin/maven-metadata.xml
> [DefaultMetadataResolver-0-1] [DEBUG] Writing tracking file
> /.../core-it-suite/target/test-classes/mng-xxxx-concurrent-writes-to-resolver-status-file/repo/mng-xxxx-concurrent-writes-to-resolver-status-file/plugin/resolver-status.properties
> [DefaultMetadataResolver-0-2] [DEBUG] Writing tracking file
> /.../core-it-suite/target/test-classes/mng-xxxx-concurrent-writes-to-resolver-status-file/repo/mng-xxxx-concurrent-writes-to-resolver-status-file/plugin/resolver-status.properties
> [DefaultMetadataResolver-0-0] [DEBUG] Writing tracking file
> /.../core-it-suite/target/test-classes/mng-xxxx-concurrent-writes-to-resolver-status-file/repo/mng-xxxx-concurrent-writes-to-resolver-status-file/plugin/resolver-status.properties
> {code}
> We [created a Maven integration
> test|https://github.com/guylabs/maven-integration-testing/commit/56edeb28895a6704ad28e76655ee792d19797a8c]
> which reproduces the issue. The test is not always failing as in some runs
> the {{null}} characters are normalized to {{\u0000}} Strings and then written
> back to the {{resolver-status.properties}} file which then can be read
> properly by the {{Properties#load()}} method. You can monitor the
> {{core-it-suite/target/test-classes/mng-xxxx-concurrent-writes-to-resolver-status-file/repo/mng-xxxx-concurrent-writes-to-resolver-status-file/plugin/resolver-status.properties}}
> file while running the test as there you'll see the corrupted updates.
> Readding the thread synchronization to the {{TrackingFileManager}} would
> solve this race condition, as file locking is indeed not required as stated
> in MRESOLVER-132.
> Can we get this change into a new Maven {{4.0.0-alpha-1-SNAPSHOT}} version to
> be able to test the fix?
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