Issue #217: Check out submodules in maven-release-plugin

pom.xml

@@ -439,6 +439,11 @@
           <artifactId>kover-maven-plugin</artifactId>
           <version>${version.io.github.martinvisser}</version>
         </plugin>
+        <plugin>
+          <groupId>org.codehaus.mojo</groupId>
+          <artifactId>exec-maven-plugin</artifactId>
+          <version>3.2.0</version>
+        </plugin>
         <plugin>
           <groupId>org.jetbrains.kotlin</groupId>
           <artifactId>kotlin-maven-plugin</artifactId>
@@ -510,6 +515,35 @@
           </dependency>
         </dependencies>
       </plugin>
+      <!--
+      This is needed because the maven-release-plugin does not check out
+      submodules, needed for Web5 Test Vectors
+
+      Idea from: https://sumit-jha.medium.com/how-to-make-maven-release-plugin-work-with-git-submodules-917825a253f2
+      -->
+      <plugin>
+        <groupId>org.codehaus.mojo</groupId>
+        <artifactId>exec-maven-plugin</artifactId>
+        <inherited>false</inherited>
+        <executions>
+          <execution>
+            <id>clone git submodule</id>
+            <phase>initialize</phase>
+            <configuration>
+              <executable>git</executable>
+              <arguments>
+                <argument>submodule</argument>
+                <argument>update</argument>
+                <argument>--init</argument>
+                <argument>--recursive</argument>
+              </arguments>
+            </configuration>
+            <goals>
+              <goal>exec</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
       <plugin>
         <groupId>org.jetbrains.kotlin</groupId>
         <artifactId>kotlin-maven-plugin</artifactId>