Don't show the DiscoveryWizard if nothing new was discovered

Currently we show a DiscoveryWizard after project import, even if no new
items are discovered. This is not really helpful for the user, as the
only thing one can do is to completely ignore an execution (what is
always possible from the pom afterwards) or cancel the dialog.

This changes the project import to not show the dialog if nothing was
found, but shows the full dialog if the user manually triggers the
discovery.

Author: laeubi

org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/project/MavenProjectConfigurator.java

@@ -65,7 +65,7 @@ public synchronized static CumulativeMappingDiscoveryJob getInstance() {
         }
 
         private CumulativeMappingDiscoveryJob() {
-            super(Collections.<IProject>emptyList());
+          super(Collections.<IProject> emptyList(), true);
             this.toProcess = Collections.synchronizedSet(new HashSet<IProject>());
         }
 

org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/wizards/ImportMavenProjectsJob.java

@@ -79,7 +79,7 @@ protected List<IProject> doCreateMavenProjects(IProgressMonitor progressMonitor)
     try {
       importOperation.run(monitor);
       List<IProject> createdProjects = importOperation.getCreatedProjects();
-      MappingDiscoveryJob discoveryJob = new MappingDiscoveryJob(createdProjects);
+      MappingDiscoveryJob discoveryJob = new MappingDiscoveryJob(createdProjects, true);
       discoveryJob.schedule();
     } catch(InvocationTargetException e) {
       return AbstractCreateMavenProjectsOperation.toStatus(e);

org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/wizards/MappingDiscoveryJob.java

@@ -15,6 +15,8 @@
 package org.eclipse.m2e.core.ui.internal.wizards;
 
 import java.util.Collection;
+import java.util.List;
+import java.util.Map;
 
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.runtime.CoreException;
@@ -27,6 +29,8 @@
 import org.eclipse.ui.PlatformUI;
 
 import org.eclipse.m2e.core.internal.jobs.MavenWorkspaceJob;
+import org.eclipse.m2e.core.internal.lifecyclemapping.discovery.ILifecycleMappingRequirement;
+import org.eclipse.m2e.core.internal.lifecyclemapping.discovery.IMavenDiscoveryProposal;
 
 
 /**
@@ -39,9 +43,24 @@ public class MappingDiscoveryJob extends MavenWorkspaceJob {
 
   private final Collection<IProject> projects;
 
+  private boolean skipOnEmpty;
+
+  @Deprecated
   public MappingDiscoveryJob(Collection<IProject> projects) {
+    this(projects, false);
+  }
+
+  /**
+   * Creates a new discovery job for the given set of projects
+   * 
+   * @param projects the projects to discover
+   * @param skipOnEmpty if <code>true</code> nothing will be done if no new proposals can be discovered, otherwise the
+   *          dialog is even shown if nothing new was discovered just showing possible unmatched items
+   */
+  public MappingDiscoveryJob(Collection<IProject> projects, boolean skipOnEmpty) {
     super("Discover lifecycle mappings");
     this.projects = projects;
+    this.skipOnEmpty = skipOnEmpty;
 
   }
 
@@ -55,7 +74,11 @@ public IStatus runInWorkspace(IProgressMonitor monitor) throws CoreException {
     }
     //Some errors were detected
     discoverProposals(discoveryRequest, monitor);
-
+    Map<ILifecycleMappingRequirement, List<IMavenDiscoveryProposal>> proposals = discoveryRequest.getAllProposals();
+    if(proposals.isEmpty() && skipOnEmpty) {
+      //if we can not propose anything, why open the dialog?
+      return Status.CANCEL_STATUS;
+    }
     openProposalWizard(projects, discoveryRequest);
 
     return Status.OK_STATUS;

org.eclipse.m2e.core.ui/src/org/eclipse/m2e/core/ui/internal/wizards/MavenProjectWizard.java

@@ -264,7 +264,7 @@ public void done(IJobChangeEvent event) {
               NLS.bind(Messages.wizardProjectJobFailed, projectName), result.getMessage()));
         }
 
-        MappingDiscoveryJob discoveryJob = new MappingDiscoveryJob(job.getCreatedProjects());
+        MappingDiscoveryJob discoveryJob = new MappingDiscoveryJob(job.getCreatedProjects(), true);
         discoveryJob.schedule();
 
       }

org.eclipse.m2e.discovery/src/org/eclipse/m2e/internal/discovery/markers/DiscoveryWizardResolution.java

@@ -68,7 +68,7 @@ public boolean canFix(IMarker marker) {
   public void fix(IMarker[] markers, IDocument document, IProgressMonitor monitor) {
     Set<IProject> projects = Stream.of(markers).map(m -> m.getResource().getProject()).collect(Collectors.toSet());
 
-    MappingDiscoveryJob discoveryJob = new MappingDiscoveryJob(projects);
+    MappingDiscoveryJob discoveryJob = new MappingDiscoveryJob(projects, false);
     discoveryJob.schedule();
   }
 }

org.eclipse.m2e.profiles.core/META-INF/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: M2E Maven Profiles Management
 Bundle-SymbolicName: org.eclipse.m2e.profiles.core;singleton:=true
-Bundle-Version: 2.1.0.qualifier
+Bundle-Version: 2.1.1.qualifier
 Require-Bundle: org.eclipse.core.runtime;bundle-version="3.7.0",
  org.eclipse.core.resources;bundle-version="3.6.0",
  org.eclipse.m2e.core;bundle-version="[2.0.0,3.0.0)",