o Added method to clone/fork model resolver which is a prerequisite for importing other POMs/mixins during the model building where the model builder basically recurses and we want the resolution processes for these sub POMs to be isolated

git-svn-id: https://svn.apache.org/repos/asf/maven/components/trunk@795227 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -82,6 +82,12 @@ class RepositoryModelResolver
         this.remoteRepositories = new ArrayList<ArtifactRepository>( remoteRepositories );
     }
 
+    public ModelResolver newCopy()
+    {
+        return new RepositoryModelResolver( repositorySystem, resolutionErrorHandler, localRepository,
+                                            remoteRepositories );
+    }
+
     public void addRepository( Repository repository )
         throws InvalidRepositoryException
     {

maven-model-builder/src/main/java/org/apache/maven/model/resolution/ModelResolver.java

@@ -55,4 +55,13 @@ public interface ModelResolver
     void addRepository( Repository repository )
         throws InvalidRepositoryException;
 
+    /**
+     * Clones this resolver for usage in a forked resolution process. In general, implementors need not provide a deep
+     * clone. The only requirement is that invocations of {@link #addRepository(Repository)} on the clone do not affect
+     * the state of the original resolver and vice versa.
+     * 
+     * @return The cloned resolver, never {@code null}.
+     */
+    ModelResolver newCopy();
+
 }