Added a new mojo that resolves plugins transitively.

pom.xml

@@ -166,6 +166,12 @@
       <artifactId>sezpoz</artifactId>
       <version>1.9</version>
     </dependency>
+    <!-- for copy-dependency-plugins -->
+    <dependency>
+      <groupId>org.apache.maven.plugins</groupId>
+      <artifactId>maven-dependency-plugin</artifactId>
+      <version>2.8</version>
+    </dependency>
     <!-- for the create goal -->
     <dependency>
       <groupId>org.apache.maven.plugins</groupId>

src/main/java/org/jenkinsci/maven/plugins/hpi/AbstractHpiMojo.java

@@ -258,15 +258,6 @@ public abstract class AbstractHpiMojo extends AbstractJenkinsMojo {
      */
     ScopeArtifactFilter scopeFilter = new ScopeArtifactFilter("runtime");
 
-    /**
-     * @component
-     */
-    protected MavenProjectBuilder projectBuilder;
-
-    /**
-     * @parameter expression="${localRepository}"
-     */
-    protected ArtifactRepository localRepository;
 
     private static final String[] EMPTY_STRING_ARRAY = {};
 

src/main/java/org/jenkinsci/maven/plugins/hpi/AbstractJenkinsMojo.java

@@ -1,9 +1,14 @@
 package org.jenkinsci.maven.plugins.hpi;
 
+import org.apache.maven.artifact.Artifact;
+import org.apache.maven.artifact.factory.ArtifactFactory;
+import org.apache.maven.artifact.metadata.ArtifactMetadataSource;
+import org.apache.maven.artifact.repository.ArtifactRepository;
 import org.apache.maven.model.Dependency;
 import org.apache.maven.plugin.AbstractMojo;
 import org.apache.maven.plugin.MojoExecutionException;
 import org.apache.maven.project.MavenProject;
+import org.apache.maven.project.MavenProjectBuilder;
 
 import java.util.List;
 
@@ -32,6 +37,37 @@ public abstract class AbstractJenkinsMojo extends AbstractMojo {
      */
     protected String jenkinsCoreId;
 
+
+    /**
+     * List of Remote Repositories used by the resolver
+     *
+     * @parameter expression="${project.remoteArtifactRepositories}"
+     * @required
+     */
+    protected List<ArtifactRepository> remoteRepos;
+
+    /**
+     * @parameter expression="${localRepository}"
+     * @required
+     */
+    protected ArtifactRepository localRepository;
+
+    /**
+     * @component
+     */
+    protected ArtifactMetadataSource artifactMetadataSource;
+
+    /**
+     * @component
+     */
+    protected ArtifactFactory artifactFactory;
+
+    /**
+     * @component
+     */
+    protected MavenProjectBuilder projectBuilder;
+
+
     protected String findJenkinsVersion() throws MojoExecutionException {
         for(Dependency a : (List<Dependency>)project.getDependencies()) {
             boolean match;
@@ -46,4 +82,8 @@ protected String findJenkinsVersion() throws MojoExecutionException {
         }
         throw new MojoExecutionException("Failed to determine Jenkins version this plugin depends on.");
     }
+
+    protected MavenArtifact wrap(Artifact a) {
+        return new MavenArtifact(a,projectBuilder,remoteRepos,localRepository);
+    }
 }

src/main/java/org/jenkinsci/maven/plugins/hpi/CopyPluginsWithDependenciesMojo.java

@@ -0,0 +1,93 @@
+package org.jenkinsci.maven.plugins.hpi;
+
+import org.apache.maven.artifact.Artifact;
+import org.apache.maven.artifact.resolver.ArtifactCollector;
+import org.apache.maven.artifact.resolver.ArtifactNotFoundException;
+import org.apache.maven.artifact.resolver.ArtifactResolutionException;
+import org.apache.maven.artifact.resolver.ArtifactResolutionResult;
+import org.apache.maven.artifact.resolver.ArtifactResolver;
+import org.apache.maven.artifact.versioning.InvalidVersionSpecificationException;
+import org.apache.maven.artifact.versioning.VersionRange;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugin.dependency.fromConfiguration.ArtifactItem;
+import org.codehaus.plexus.util.FileUtils;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import static org.apache.maven.artifact.Artifact.*;
+
+/**
+ * Resolve plugin dependencies transitively and copy them all into a specific directory.
+ *
+ * @author Kohsuke Kawaguchi
+ * @goal copy-plugins-with-dependencies
+ */
+public class CopyPluginsWithDependenciesMojo extends AbstractJenkinsMojo {
+    /**
+     * Collection of plugins to copy from
+     *
+     * @parameter
+     */
+    private List<ArtifactItem> artifactItems;
+
+    /**
+     * Where to copy plugins into.
+     *
+     * @parameter
+     */
+    private File outputDirectory;
+
+    /**
+     * @component
+     */
+    protected ArtifactResolver resolver;
+
+    /**
+     * @component
+     */
+    protected ArtifactCollector artifactCollector;
+
+
+    public void execute() throws MojoExecutionException, MojoFailureException {
+        try {
+            Set<Artifact> all = new HashSet<Artifact>();
+
+            for (ArtifactItem ai : artifactItems) {
+                all.add(toArtifact(ai));
+            }
+
+            ArtifactResolutionResult r = resolver.resolveTransitively(all, project.getArtifact(), remoteRepos, localRepository, artifactMetadataSource);
+            for (Artifact o : (Set<Artifact>)r.getArtifacts()) {
+                if (wrap(o).isPlugin()) {
+                    getLog().debug("Copying "+o.getFile());
+
+                    Artifact hpi = artifactFactory.createArtifact(o.getGroupId(),o.getArtifactId(),o.getVersion(),SCOPE_COMPILE,"hpi");
+                    resolver.resolve(hpi,remoteRepos,localRepository);
+
+                    FileUtils.copyFile(hpi.getFile(), new File(outputDirectory,hpi.getArtifactId()+".hpi"));
+                }
+            }
+
+        } catch (InvalidVersionSpecificationException e) {
+            throw new MojoExecutionException("Failed to resolve plugin dependencies",e);
+        } catch (ArtifactResolutionException e) {
+            throw new MojoExecutionException("Failed to resolve plugin dependencies",e);
+        } catch (ArtifactNotFoundException e) {
+            throw new MojoExecutionException("Failed to resolve plugin dependencies",e);
+        } catch (IOException e) {
+            throw new MojoExecutionException("Failed to resolve plugin dependencies",e);
+        }
+    }
+
+    private Artifact toArtifact(ArtifactItem ai) throws InvalidVersionSpecificationException {
+        VersionRange vr = VersionRange.createFromVersionSpec(ai.getVersion());
+
+        return artifactFactory.createDependencyArtifact(ai.getGroupId(), ai.getArtifactId(), vr,
+                "hpi", ai.getClassifier(), SCOPE_COMPILE);
+    }
+}