How to get Maven release to clone git submodules?

git, git-submodules, maven

Solution

I just added the following plugin:

<!-- This is a workaround to get submodules working with the maven release plugin -->
<plugin>
    <groupId>org.codehaus.mojo</groupId>
    <artifactId>exec-maven-plugin</artifactId>
    <version>1.1</version>
    <executions>
        <execution>
            <phase>initialize</phase>
            <id>invoke build</id>
            <goals>
                <goal>exec</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <executable>git</executable>
        <arguments>
           <argument>submodule</argument>
           <argument>update</argument>
           <argument>--init</argument>
           <argument>--recursive</argument>
        </arguments>
    </configuration>
</plugin>

Problem

I've got a Maven project with some git submodules linked. Everything works fine until I do a release:prepare or :perform, the clean checkout these targets perform does not contain the submodules (or in other words, git clone is not recursive). I could not find a proper way to configure Maven to call git clone with the --recursive option. I was thinking of using the scm provider configuration (http://maven.apache.org/scm/git.html) or simply to configure the release plugin directly in the pom.xml, but couldn't get it to work. Thanks.

Original source