Building a p2 repository with tycho

1. Use packing type
     <packaging>eclipse-repository</packaging>
2. Use plugin
     <build>
       <plugins>
         <plugin>
           <groupId>org.eclipse.tycho</groupId>
           <artifactId>tycho-p2-publisher-plugin</artifactId>
           <version>${tycho-version}</version>
           <configuration>
             <publishArtifacts>true</publishArtifacts>
           </configuration>
         </plugin>
       </plugins>
     </build>
3. What's included in the repository depends on which files are present in the project. The plugin executes 2 commands tycho-p2-publisher-plugin:publish-products and tycho-p2-publisher-plugin:publish-categories. It seems that publish-products looks a a *.product file in the project and adds all features referenced in this file to the repository. The publish-categories command searches for a categories.xml and adds the features referenced here to the repository. To limit the repository content to only the new plugins without any dependencies it is best to create a separate project with just a categories.xml file for the repository and use a different project for the product build. This way the product can contain additional eclipse features that need not be part of the repository.