MNG-5775 Make the project graph building code pluggable to allow for new/different implementations.

Author: Jason van Zyl

maven-aether-provider/src/main/java/org/apache/maven/repository/internal/DefaultArtifactDescriptorReader.java

@@ -52,6 +52,7 @@
 import org.eclipse.aether.impl.RepositoryEventDispatcher;
 import org.eclipse.aether.impl.VersionRangeResolver;
 import org.eclipse.aether.impl.VersionResolver;
+import org.eclipse.aether.repository.WorkspaceReader;
 import org.eclipse.aether.repository.WorkspaceRepository;
 import org.eclipse.aether.resolution.ArtifactDescriptorException;
 import org.eclipse.aether.resolution.ArtifactDescriptorPolicy;
@@ -215,7 +216,6 @@ public ArtifactDescriptorResult readArtifactDescriptor( RepositorySystemSession
         ArtifactDescriptorResult result = new ArtifactDescriptorResult( request );
 
         Model model = loadPom( session, request, result );
-
         if ( model != null )
         {
             Map<String, Object> config = session.getConfigProperties();
@@ -303,6 +303,18 @@ private Model loadPom( RepositorySystemSession session, ArtifactDescriptorReques
             }
 
             Model model;
+
+            // hack: don't rebuild model if it was already loaded during reactor resolution
+            final WorkspaceReader workspace = session.getWorkspaceReader();
+            if ( workspace instanceof MavenWorkspaceReader )
+            {
+                model = ( (MavenWorkspaceReader) workspace ).findModel( pomArtifact );
+                if ( model != null )
+                {
+                    return model;
+                }
+            }
+
             try
             {
                 ModelBuildingRequest modelRequest = new DefaultModelBuildingRequest();

maven-aether-provider/src/main/java/org/apache/maven/repository/internal/MavenWorkspaceReader.java

@@ -0,0 +1,32 @@
+package org.apache.maven.repository.internal;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import org.apache.maven.model.Model;
+import org.eclipse.aether.artifact.Artifact;
+import org.eclipse.aether.repository.WorkspaceReader;
+
+public interface MavenWorkspaceReader
+    extends WorkspaceReader
+{
+
+    Model findModel( Artifact artifact );
+
+}