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https://issues.apache.org/jira/browse/MRESOLVER-153?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17255522#comment-17255522
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Guy Brand commented on MRESOLVER-153:
-------------------------------------
[~michael-o] Regarding
> Why do you pass {{-Daether.updateCheckManager.sessionState=false}}? What
> happens when you leave this out?
With this flag set, the problem is reproducible more often as it will check the
dependencies every time and doesn't store it in the session.
> Can you try {{-Daether.metadataResolver.threads=1}} for testing purposes?
I executed a run of all our integration tests and they passed. We'll then keep
this flag set until this is fixed in a future Maven nightly version.
Regarding the synchronization: There you already discussed on how to restore
it. My two cents on that topic are the following:
There is the concept of a {{SyncContext}} and components as the
{{TrackingFileManager}} rely on this to implement proper synchronization. Why
having a {{DefaultSyncContext}} in place that does no synchronization at all?
Having this noop {{SyncContext}} could produce other errors like the one I
reported. Therefore instead of checking if the {{DefaultSyncContext}} is used
in the {{TrackingFileManager}}, why not just implement basic synchronization in
the {{DefaultSyncContext, }}rely on it and on top prevent similar errors on the
other usages of {{SyncContext}}?
> 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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