Provide error message regarding extensions for the gallery (#2864)

appinventor/appengine/src/com/google/appinventor/client/OdeMessages.java

@@ -97,6 +97,10 @@ public interface OdeMessages extends Messages, AutogeneratedOdeMessages {
   @Description("Error given if login fails for some reason")
   String GalleryLoginError();
 
+  @DefaultMessage("Projects with extensions cannot be published to the gallery.")
+  @Description("Error given if project contains extensions")
+  String HasExtensionError();
+
   @DefaultMessage("Show Warnings")
   @Description("Text on Toggle Warning Button")
   String showWarnings();

appinventor/appengine/src/com/google/appinventor/client/actions/SendToGalleryAction.java

@@ -32,6 +32,10 @@ public class SendToGalleryAction implements Command {
         ErrorReporter.reportInfo(MESSAGES.selectOnlyOneProject());
       } else {
         if (!lockPublishButton) {
+          if (Ode.getInstance().getCurrentYoungAndroidProjectRootNode().hasExtensions()) {
+            ErrorReporter.reportError(MESSAGES.HasExtensionError());
+            return;
+          }
           lockPublishButton = true;
           Project project = selectedProjects.get(0);
           Ode.getInstance().getProjectService().sendToGallery(project.getProjectId(),

appinventor/appengine/src/com/google/appinventor/client/editor/youngandroid/actions/SendToGalleryAction.java

@@ -35,6 +35,10 @@ public class SendToGalleryAction implements Command {
           + "Ignoring SendToGalleryAction.execute().");
       return;
     }
+    if (Ode.getInstance().getCurrentYoungAndroidProjectRootNode().hasExtensions()) {
+      ErrorReporter.reportError(MESSAGES.HasExtensionError());
+      return;
+    }
     boolean shouldRun;
     try {
       shouldRun = before.call();

appinventor/appengine/src/com/google/appinventor/shared/rpc/project/ProjectNode.java

@@ -175,7 +175,7 @@ public abstract class ProjectNode implements Serializable, IsSerializable {
    *
    * @return iterable
    */
-  public Iterable<ProjectNode> getChildren() {
+  public List<ProjectNode> getChildren() {
     List<ProjectNode> result = children;
     if (result == null) {
       result = Collections.emptyList();
@@ -264,4 +264,13 @@ public abstract class ProjectNode implements Serializable, IsSerializable {
   public void setName(String newName) {
     name = newName;
   }
+  
+  /**
+   * Checks if project has extension or not.
+   *
+   * @return boolean;
+   */
+  public boolean hasExtensions() {
+    return false;
+  }
 }

appinventor/appengine/src/com/google/appinventor/shared/rpc/project/youngandroid/YoungAndroidProjectNode.java

@@ -101,4 +101,11 @@ public final class YoungAndroidProjectNode extends ProjectRootNode
     throw new IllegalStateException("Couldn't find component folder");
   }
   
+  @Override
+  public boolean hasExtensions() {
+    if (getComponentsFolder().getChildren().size() > 0) {
+      return true;
+    }
+    return false;
+  }
 }