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[3.8.x] [MNG-7476] Display a warning when an aggregator mojo locks other mojos executions #736

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merged 2 commits into from May 30, 2022
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[3.8.x] [MNG-7476] Display a warning when an aggregator mojo locks other mojos executions #736

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67426e9
[MNG-7487] Fix deadlock during forked lifecycle executions
gnodet May 12, 2022
393a5fa
[MNG-7476] Display a warning when an aggregator mojo is locking other…
gnodet May 16, 2022
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110 changes: 86 additions & 24 deletions maven-core/src/main/java/org/apache/maven/lifecycle/internal/MojoExecutor.java
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Expand Up @@ -24,6 +24,7 @@
import org.apache.maven.artifact.resolver.filter.CumulativeScopeArtifactFilter;
import org.apache.maven.execution.ExecutionEvent;
import org.apache.maven.execution.MavenSession;
import org.apache.maven.internal.MultilineMessageHelper;
import org.apache.maven.lifecycle.LifecycleExecutionException;
import org.apache.maven.lifecycle.MissingProjectException;
import org.apache.maven.plugin.BuildPluginManager;
Expand All @@ -40,6 +41,8 @@
import org.codehaus.plexus.component.annotations.Requirement;
import org.codehaus.plexus.util.StringUtils;
import org.eclipse.aether.SessionData;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.ArrayList;
import java.util.Arrays;
Expand All @@ -52,7 +55,6 @@
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

Expand All @@ -71,6 +73,8 @@
public class MojoExecutor
{

private static final Logger LOGGER = LoggerFactory.getLogger( MojoExecutor.class );

@Requirement
private BuildPluginManager pluginManager;

Expand All @@ -83,7 +87,9 @@ public class MojoExecutor
@Requirement
private ExecutionEventCatapult eventCatapult;

private final ReadWriteLock aggregatorLock = new ReentrantReadWriteLock();
private final OwnerReentrantReadWriteLock aggregatorLock = new OwnerReentrantReadWriteLock();

private final Map<Thread, MojoDescriptor> mojos = new ConcurrentHashMap<>();

public MojoExecutor()
{
Expand Down Expand Up @@ -206,10 +212,7 @@ private void execute( MavenSession session, MojoExecution mojoExecution, Project
}
}

try ( ProjectLock lock = new ProjectLock( session, mojoDescriptor, aggregatorLock ) )
{
doExecute( session, mojoExecution, projectIndex, dependencyContext );
}
doExecute( session, mojoExecution, projectIndex, dependencyContext );
}

/**
Expand All @@ -220,20 +223,44 @@ private void execute( MavenSession session, MojoExecution mojoExecution, Project
* TODO: ideally, the builder should take care of the ordering in a smarter way
* TODO: and concurrency issues fixed with MNG-7157
*/
private static class ProjectLock implements AutoCloseable
private class ProjectLock implements AutoCloseable
{
final Lock acquiredAggregatorLock;
final Lock acquiredProjectLock;
final OwnerReentrantLock acquiredProjectLock;

ProjectLock( MavenSession session, MojoDescriptor mojoDescriptor, ReadWriteLock aggregatorLock )
ProjectLock( MavenSession session, MojoDescriptor mojoDescriptor )
{
mojos.put( Thread.currentThread(), mojoDescriptor );
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if ( session.getRequest().getDegreeOfConcurrency() > 1 )
{
boolean aggregator = mojoDescriptor.isAggregator();
acquiredAggregatorLock = aggregator ? aggregatorLock.writeLock() : aggregatorLock.readLock();
acquiredProjectLock = getProjectLock( session );
acquiredAggregatorLock.lock();
acquiredProjectLock.lock();
if ( !acquiredAggregatorLock.tryLock() )
{
Thread owner = aggregatorLock.getOwner();
MojoDescriptor ownerMojo = owner != null ? mojos.get( owner ) : null;
String str = ownerMojo != null ? " The " + ownerMojo.getId() : "An";
String msg = str + " aggregator mojo is already being executed "
+ "in this parallel build, those kind of mojos require exclusive access to "
+ "reactor to prevent race conditions. This mojo execution will be blocked "
+ "until the aggregator mojo is done.";
warn( msg );
acquiredAggregatorLock.lock();
}
if ( !acquiredProjectLock.tryLock() )
{
Thread owner = acquiredProjectLock.getOwner();
MojoDescriptor ownerMojo = owner != null ? mojos.get( owner ) : null;
String str = ownerMojo != null ? " The " + ownerMojo.getId() : "A";
String msg = str + " mojo is already being executed "
+ "on the project " + session.getCurrentProject().getGroupId()
+ ":" + session.getCurrentProject().getArtifactId() + ". "
+ "This mojo execution will be blocked "
+ "until the mojo is done.";
warn( msg );
acquiredProjectLock.lock();
}
}
else
{
Expand All @@ -254,25 +281,26 @@ public void close()
{
acquiredAggregatorLock.unlock();
}
mojos.remove( Thread.currentThread() );
}

@SuppressWarnings( { "unchecked", "rawtypes" } )
private Lock getProjectLock( MavenSession session )
private OwnerReentrantLock getProjectLock( MavenSession session )
{
SessionData data = session.getRepositorySession().getData();
ConcurrentMap<MavenProject, Lock> locks = ( ConcurrentMap ) data.get( ProjectLock.class );
ConcurrentMap<MavenProject, OwnerReentrantLock> locks = ( ConcurrentMap ) data.get( ProjectLock.class );
// initialize the value if not already done (in case of a concurrent access) to the method
if ( locks == null )
{
// the call to data.set(k, null, v) is effectively a call to data.putIfAbsent(k, v)
data.set( ProjectLock.class, null, new ConcurrentHashMap<>() );
locks = ( ConcurrentMap ) data.get( ProjectLock.class );
}
Lock acquiredProjectLock = locks.get( session.getCurrentProject() );
OwnerReentrantLock acquiredProjectLock = locks.get( session.getCurrentProject() );
if ( acquiredProjectLock == null )
{
acquiredProjectLock = new ReentrantLock();
Lock prev = locks.putIfAbsent( session.getCurrentProject(), acquiredProjectLock );
acquiredProjectLock = new OwnerReentrantLock();
OwnerReentrantLock prev = locks.putIfAbsent( session.getCurrentProject(), acquiredProjectLock );
if ( prev != null )
{
acquiredProjectLock = prev;
Expand All @@ -282,6 +310,32 @@ private Lock getProjectLock( MavenSession session )
}
}

static class OwnerReentrantLock extends ReentrantLock
{
@Override
public Thread getOwner()
{
return super.getOwner();
}
}

static class OwnerReentrantReadWriteLock extends ReentrantReadWriteLock
{
@Override
public Thread getOwner()
{
return super.getOwner();
}
}

private static void warn( String msg )
{
for ( String s : MultilineMessageHelper.format( msg ) )
{
LOGGER.warn( s );
}
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}

private void doExecute( MavenSession session, MojoExecution mojoExecution, ProjectIndex projectIndex,
DependencyContext dependencyContext )
throws LifecycleExecutionException
Expand All @@ -292,8 +346,23 @@ private void doExecute( MavenSession session, MojoExecution mojoExecution, Proje

ensureDependenciesAreResolved( mojoDescriptor, session, dependencyContext );

eventCatapult.fire( ExecutionEvent.Type.MojoStarted, session, mojoExecution );
try ( ProjectLock lock = new ProjectLock( session, mojoDescriptor ) )
{
doExecute2( session, mojoExecution );
}
finally
{
for ( MavenProject forkedProject : forkedProjects )
{
forkedProject.setExecutionProject( null );
}
}
}

private void doExecute2( MavenSession session, MojoExecution mojoExecution )
throws LifecycleExecutionException
{
eventCatapult.fire( ExecutionEvent.Type.MojoStarted, session, mojoExecution );
try
{
try
Expand All @@ -314,13 +383,6 @@ private void doExecute( MavenSession session, MojoExecution mojoExecution, Proje

throw e;
}
finally
{
for ( MavenProject forkedProject : forkedProjects )
{
forkedProject.setExecutionProject( null );
}
}
}

public void ensureDependenciesAreResolved( MojoDescriptor mojoDescriptor, MavenSession session,
Expand Down