Maven release plugin fails : source artifacts getting deployed twice

Try running mvn -Prelease-profile help:effective-pom.
You will find that you have two execution sections for maven-source-plugin

The output will look something like this:

    <plugin>

      <artifactId>maven-source-plugin</artifactId>
      <version>2.0.4</version>
      <executions>
        <execution>
          <id>attach-sources</id>
          <goals>
            <goal>jar</goal>
          </goals>
        </execution>
        <execution>
          <goals>
            <goal>jar</goal>
          </goals>
        </execution>
      </executions>
    </plugin>

To fix this problem, find everywhere you have used maven-source-plugin and make sure that you use the “id” attach-sources so that it is the same as the release profile. Then these sections will be merged.

Best practice says that to get consistency you need to configure this in the root POM of your project in build > pluginManagement and NOT in your child poms. In the child pom you just specify in build > plugins that you want to use maven-source-plugin but you provide no executions.

In the root pom.xml:

<build>
  <pluginManagement>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-source-plugin</artifactId>
        <executions>
          <execution>
            <!-- This id must match the -Prelease-profile id value or else sources will be "uploaded" twice, which causes Nexus to fail -->
            <id>attach-sources</id>
            <goals>
              <goal>jar</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
    </plugins>    
  </pluginManagement>
</build>

In the child pom.xml:

<build>
  <plugins>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-source-plugin</artifactId>
    </plugin>
  </plugins>
</build>