Configuring the GMaven Plugin for Groovy Support in Maven 2 and 3

If you are using Clover-for-Maven 2 and 3 on Groovy code, you would typically need to define a plugin element for the GMaven Plugin in your pom.xml file.

As shown in the example definition below, the GMaven Plugin definition requires the Groovy dependency (groovy-all). However, within this dependency, you must define a version of Groovy that Clover supports inside a version sub-element. If you omit this version element, the GMaven Plugin will default to using Groovy version 1.6.0, which is not compatible with Clover.

<properties>
  <groovy.version>1.8.8</groovy.version>
  <gmaven.version>1.5</gmaven.version>
</properties>
...
<plugins>
  <plugin>
    <groupId>org.codehaus.gmaven</groupId>
    <artifactId>gmaven-plugin</artifactId>
    <version>${gmaven.version}</version>
    <configuration>
      <providerSelection>1.8</providerSelection>
    </configuration>
    <dependencies>
      <dependency>
        <groupId>org.codehaus.gmaven.runtime</groupId>
        <artifactId>gmaven-runtime-1.8</artifactId>
        <version>${gmaven.version}</version>
      </dependency>
      <dependency>
        <groupId>org.codehaus.groovy</groupId>
        <artifactId>groovy-all</artifactId>
        <version>${groovy.version}</version>
        </dependency>
    </dependencies>
    <executions>
      <execution>
        <goals>
          <goal>generateStubs</goal>
          <goal>compile</goal>
          <goal>generateTestStubs</goal>
          <goal>testCompile</goal>
        </goals>
      </execution>
    </executions>
  </plugin>
</plugins>

Tips

Cross-compilation

If you use cross-compilation with Groovy code, please refer to the Cross Compilation using Groovy on the Best Practices for Maven page.

Stub generation

Use the clover2:setup goal for Clover instrumentation in case you have generateStubs or generateTestStubs goal declared in GMaven plugin configuration.

In case you use clover2:instrument a build will fail with an error message like:

org.apache.maven.BuildFailureException: Compilation failure
... error: duplicate class: com.acme.MyClass

A reason is that GMaven will generate stubs twice and will add /generated-sources/groovy-stubs source root for both the default build life cycle (/target) and the Clover's forked build life cycle (/target/clover) resulting in duplicated source files passed to the Maven compiler.

Setting the providerSelection

Remember to configure a providerSelection parameter. Otherwise build might fail with the following error: "org.apache.maven.lifecycle.LifecycleExecutionException: Unexpected node: Node[7:1,64,ANNOTATIONS]" (see stackoverflow).

Code example

See https://bitbucket.org/atlassian/maven-clover2-plugin repository, src/it/groovy directory.