copy aggregate compare only on last (#188)

Author: hboutemy

src/main/java/org/apache/maven/plugins/artifact/buildinfo/AbstractBuildinfoMojo.java

@@ -377,7 +377,7 @@ protected Map<Artifact, String> generateBuildinfo(boolean mono) throws MojoExecu
         }
     }
 
-    private MavenProject getLastProject() {
+    protected MavenProject getLastProject() {
         int i = session.getProjects().size();
         while (i > 0) {
             MavenProject project = session.getProjects().get(--i);

src/main/java/org/apache/maven/plugins/artifact/buildinfo/CompareMojo.java

@@ -248,7 +248,12 @@ private void compareWithReference(Map<Artifact, String> artifacts, File referenc
         } else {
             getLog().info(saved);
         }
-        buildcompare = copyAggregateToRoot(buildcompare);
+        if (session.getProjects().size() > 1) {
+            MavenProject last = getLastProject();
+            if (project == last) {
+                buildcompare = copyAggregateToRoot(buildcompare);
+            }
+        }
 
         if (ko + missing > 0) {
             getLog().error("[Reproducible Builds] to analyze the differences, see diffoscope instructions in "