From 9d1575e849283922b216c82b461ba65a5410dcb5 Mon Sep 17 00:00:00 2001
From: Guillaume Nodet <gnodet@gmail.com>
Date: Tue, 12 Apr 2022 14:04:33 +0200
Subject: [PATCH 1/2] Attempt to use a single session

---
 .../org/apache/maven/execution/MavenSession.java   | 13 +++++++------
 .../lifecycle/internal/BuildListCalculator.java    |  4 +---
 .../lifecycle/internal/LifecycleModuleBuilder.java | 14 +++-----------
 3 files changed, 11 insertions(+), 20 deletions(-)

diff --git a/maven-core/src/main/java/org/apache/maven/execution/MavenSession.java b/maven-core/src/main/java/org/apache/maven/execution/MavenSession.java
index 5b56df36d003..aa2ae50a6537 100644
--- a/maven-core/src/main/java/org/apache/maven/execution/MavenSession.java
+++ b/maven-core/src/main/java/org/apache/maven/execution/MavenSession.java
@@ -54,7 +54,7 @@ public class MavenSession
 
     private Properties executionProperties;
 
-    private MavenProject currentProject;
+    private InheritableThreadLocal<MavenProject> currentProject = new InheritableThreadLocal<>();
 
     /**
      * These projects have already been topologically sorted in the {@link org.apache.maven.Maven} component before
@@ -83,8 +83,9 @@ public void setProjects( List<MavenProject> projects )
     {
         if ( !projects.isEmpty() )
         {
-            this.currentProject = projects.get( 0 );
-            this.topLevelProject = currentProject;
+            MavenProject prj = projects.get( 0 );
+            this.currentProject.set( prj );
+            this.topLevelProject = prj;
             for ( MavenProject project : projects )
             {
                 if ( project.isExecutionRoot() )
@@ -96,7 +97,7 @@ public void setProjects( List<MavenProject> projects )
         }
         else
         {
-            this.currentProject = null;
+            this.currentProject.set( null );
             this.topLevelProject = null;
         }
         this.projects = projects;
@@ -157,12 +158,12 @@ public MavenExecutionRequest getRequest()
 
     public void setCurrentProject( MavenProject currentProject )
     {
-        this.currentProject = currentProject;
+        this.currentProject.set( currentProject );
     }
 
     public MavenProject getCurrentProject()
     {
-        return currentProject;
+        return currentProject.get();
     }
 
     public ProjectBuildingRequest getProjectBuildingRequest()
diff --git a/maven-core/src/main/java/org/apache/maven/lifecycle/internal/BuildListCalculator.java b/maven-core/src/main/java/org/apache/maven/lifecycle/internal/BuildListCalculator.java
index 4fef69b4a9c7..0e0262779c0f 100644
--- a/maven-core/src/main/java/org/apache/maven/lifecycle/internal/BuildListCalculator.java
+++ b/maven-core/src/main/java/org/apache/maven/lifecycle/internal/BuildListCalculator.java
@@ -61,9 +61,7 @@ public ProjectBuildList calculateProjectBuilds( MavenSession session, List<TaskS
                 try
                 {
                     BuilderCommon.attachToThread( project ); // Not totally sure if this is needed for anything
-                    MavenSession copiedSession = session.clone();
-                    copiedSession.setCurrentProject( project );
-                    projectBuilds.add( new ProjectSegment( project, taskSegment, copiedSession ) );
+                    projectBuilds.add( new ProjectSegment( project, taskSegment, session ) );
                 }
                 finally
                 {
diff --git a/maven-core/src/main/java/org/apache/maven/lifecycle/internal/LifecycleModuleBuilder.java b/maven-core/src/main/java/org/apache/maven/lifecycle/internal/LifecycleModuleBuilder.java
index 1cbaf5334606..97acde3f3472 100644
--- a/maven-core/src/main/java/org/apache/maven/lifecycle/internal/LifecycleModuleBuilder.java
+++ b/maven-core/src/main/java/org/apache/maven/lifecycle/internal/LifecycleModuleBuilder.java
@@ -88,13 +88,10 @@ public void buildProject( MavenSession session, MavenSession rootSession, Reacto
 
         long buildStartTime = System.currentTimeMillis();
 
-        // session may be different from rootSession seeded in DefaultMaven
-        // explicitly seed the right session here to make sure it is used by Guice
-        final boolean scoped = session != rootSession;
-        if ( scoped )
+        if ( session != rootSession )
         {
-            sessionScope.enter();
-            sessionScope.seed( MavenSession.class, session );
+            // a single session is reused during the whole build
+            throw new UnsupportedOperationException();
         }
         try
         {
@@ -149,11 +146,6 @@ public void buildProject( MavenSession session, MavenSession rootSession, Reacto
         }
         finally
         {
-            if ( scoped )
-            {
-                sessionScope.exit();
-            }
-
             session.setCurrentProject( null );
 
             Thread.currentThread().setContextClassLoader( reactorContext.getOriginalContextClassLoader() );

From 7103d192a647df7be5b0440352f5e8c16c1f8bc5 Mon Sep 17 00:00:00 2001
From: Guillaume Nodet <gnodet@gmail.com>
Date: Tue, 12 Apr 2022 15:38:49 +0200
Subject: [PATCH 2/2] Make MavenSession#getExecutionProperties() thread safe

---
 .../org/apache/maven/execution/MavenSession.java   | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/maven-core/src/main/java/org/apache/maven/execution/MavenSession.java b/maven-core/src/main/java/org/apache/maven/execution/MavenSession.java
index aa2ae50a6537..2f4322b89b19 100644
--- a/maven-core/src/main/java/org/apache/maven/execution/MavenSession.java
+++ b/maven-core/src/main/java/org/apache/maven/execution/MavenSession.java
@@ -52,7 +52,7 @@ public class MavenSession
 
     private RepositorySystemSession repositorySession;
 
-    private Properties executionProperties;
+    private volatile Properties executionProperties;
 
     private InheritableThreadLocal<MavenProject> currentProject = new InheritableThreadLocal<>();
 
@@ -397,9 +397,15 @@ public Properties getExecutionProperties()
     {
         if ( executionProperties == null )
         {
-            executionProperties = new Properties();
-            executionProperties.putAll( request.getSystemProperties() );
-            executionProperties.putAll( request.getUserProperties() );
+            synchronized ( this )
+            {
+                if ( executionProperties == null )
+                {
+                    executionProperties = new Properties();
+                    executionProperties.putAll( request.getSystemProperties() );
+                    executionProperties.putAll( request.getUserProperties() );
+                }
+            }
         }
 
         return executionProperties;