o Fixed project realm handling to be more embedder friendly

git-svn-id: https://svn.apache.org/repos/asf/maven/components/trunk@795206 13f79535-47bb-0310-9956-ffa450edef68

maven-core/src/main/java/org/apache/maven/project/DefaultModelBuildingListener.java

@@ -97,12 +97,15 @@ class DefaultModelBuildingListener
                 projectBuildingHelper.createProjectRealm( model, projectBuildingRequest.getLocalRepository(),
                                                           pluginRepositories );
 
-            /*
+            if ( projectRealm != null )
-             * Update the context class loader so that the container will search the project realm when the model
+            {
-             * builder injects the lifecycle bindings from the packaging next. The class loader is reset by the project
+                /*
-             * builder when the project is fully assembled.
+                 * Update the context class loader such that the container will search the project realm when the model
-             */
+                 * builder injects the lifecycle bindings from the packaging in the next step. The context class loader
-            Thread.currentThread().setContextClassLoader( projectRealm );
+                 * will be reset by the project builder when the project is fully assembled.
+                 */
+                Thread.currentThread().setContextClassLoader( projectRealm );
+            }
         }
     }
 

maven-core/src/main/java/org/apache/maven/project/DefaultProjectBuilder.java

@@ -302,7 +302,23 @@ public class DefaultProjectBuilder
             .setRemoteRepostories( project.getRemoteArtifactRepositories() )
             .setManagedVersionMap( project.getManagedVersionMap() );
 
-        ArtifactResolutionResult result = repositorySystem.resolve( artifactRequest );
+        ArtifactResolutionResult result;
+
+        ClassLoader oldContextClassLoader = Thread.currentThread().getContextClassLoader();
+
+        try
+        {
+            if ( project.getClassRealm() != null )
+            {
+                Thread.currentThread().setContextClassLoader( project.getClassRealm() );
+            }
+
+            result = repositorySystem.resolve( artifactRequest );
+        }
+        finally
+        {
+            Thread.currentThread().setContextClassLoader( oldContextClassLoader );
+        }
 
         if ( result.hasExceptions() )
         {

maven-core/src/main/java/org/apache/maven/project/DefaultProjectBuildingHelper.java

@@ -98,7 +98,7 @@ public class DefaultProjectBuildingHelper
                                           List<ArtifactRepository> remoteRepositories )
         throws ArtifactResolutionException
     {
-        ClassRealm projectRealm = container.getContainerRealm();
+        ClassRealm projectRealm = null;
 
         Build build = model.getBuild();
 

maven-core/src/main/java/org/apache/maven/project/ProjectBuildingHelper.java

@@ -55,7 +55,7 @@ public interface ProjectBuildingHelper
      * @param model The model to create the project realm for, must not be {@code null}
      * @param localRepository The local repository to use for artifact resolution, must not be {@code null}.
      * @param remoteRepositories The remote repositories to use for artifact resolution, must not be {@code null}.
-     * @return The project realm, never {@code null}.
+     * @return The project realm or {@code null} if the project uses no extensions.
      * @throws ArtifactResolutionException If any build extension could not be resolved.
      */
     ClassRealm createProjectRealm( Model model, ArtifactRepository localRepository,