Create and install de-lomboked source jar in maven

Question

Disclaimer: I have solved this problem and am documenting the solution for the world to know.

How do I create and install a *-sources.jar containing "delomboked" source code in maven?

By default, The maven-source-plugin creates a sources jar without delomboking the source files, which causes projects that depend on the library binaries to complain about mismatching source files.

Answer 1

TL;DR (explained beneath)

Add the following plugins configuration to your plugins configuration in the project.build element of your pom.xml

<project>
    ...
<build>
<plugins>
    ...
<plugin>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok-maven-plugin</artifactId>
    <version>1.18.0.0</version>
    <executions>
        <execution>
            <phase>generate-sources</phase>
            <goals>
                <goal>delombok</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <sourceDirectory>src/main/java</sourceDirectory>
        <outputDirectory>${project.build.directory}/delombok</outputDirectory>
        <addOutputDirectory>false</addOutputDirectory>
        <encoding>UTF-8</encoding>
    </configuration>
</plugin>
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-resources-plugin</artifactId>
    <version>3.1.0</version>
    <executions>
        <execution>
            <id>copy-to-lombok-build</id>
            <phase>process-resources</phase>
            <goals>
                <goal>copy-resources</goal>
            </goals>
            <configuration>
                <resources>
                    <resource>
                        <directory>${project.basedir}/src/main/resources</directory>
                    </resource>
                </resources>
                <outputDirectory>${project.build.directory}/delombok</outputDirectory>
            </configuration>
        </execution>
    </executions>
</plugin>
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-antrun-plugin</artifactId>
    <version>1.8</version>
    <executions>
        <execution>
            <id>generate-delomboked-sources-jar</id>
            <phase>package</phase>
            <goals>
                <goal>run</goal>
            </goals>
            <configuration>
                <target>
                    <jar destfile="${project.build.directory}/${project.build.finalName}-sources.jar"
                         basedir="${project.build.directory}/delombok"/>
                </target>
            </configuration>
        </execution>
    </executions>
</plugin>
<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-install-plugin</artifactId>
    <version>2.5.2</version>
    <executions>
        <execution>
            <id>install-source-jar</id>
            <goals>
                <goal>install-file</goal>
            </goals>
            <phase>install</phase>
            <configuration>
                <file>${project.build.directory}/${project.build.finalName}-sources.jar</file>
                <groupId>${project.groupId}</groupId>
                <artifactId>${project.artifactId}</artifactId>
                <version>${project.version}</version>
                <classifier>sources</classifier>
                <generatePom>true</generatePom>
                <pomFile>${project.basedir}/pom.xml</pomFile>
            </configuration>
        </execution>
    </executions>
</plugin>
</plugins>
</build>
</project>

Explanation

lombok-maven-plugin will enable you to delombok the source code (${project.basedir}/src/main/java) and place it in the target directory (${project.build.directory}/delombok). Usually this will place the code in the ${project.build.directory}/generated-sources/delombok folder, but because Intellij automatically considers this additional source-code, duplicate code errors will occur when developing your library, in order to stop this, just specify a non-default target directory (in this case just outside of the generated-sources dir).

maven-resources-plugin is necessary in order to also copy resources from the standard ${project.basedir}/src/main/resources directory. If there are any other non-standard resource directories in your project, you should configure them in the resources section for this plugin.

maven-antrun-plugin is used instead of the maven-source-plugin because you cannot specify a custom source directory in the latter. The jar task points to our custom "generated-sources" and produces the standard-named sources jar.

maven-install-plugin install-file goal is used because you cannot attach jars using the install goal. We can hack a solution by manually installing a file using the install-file goal with a classifier of sources.

I hope this helps others who are on struggle street like I was with this problem.