How can I configure the moditect-maven-plugin to use the auto-value library in my modular application?

Question

I'm trying to build a modular application, and I'm attempting to use the moditect-maven-plugin in order to use the auto-value library (which is not modular).

Based on the instructions here, I came up with the following pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>org.example</groupId>
<artifactId>moditect-test</artifactId>
<version>1.0-SNAPSHOT</version>

<dependencies>
    <dependency>
        <groupId>com.google.auto.value</groupId>
        <artifactId>auto-value-annotations</artifactId>
        <version>${auto-value.version}</version>
    </dependency>
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
                <annotationProcessorPaths>
                    <path>
                        <groupId>com.google.auto.value</groupId>
                        <artifactId>auto-value</artifactId>
                        <version>${auto-value.version}</version>
                    </path>
                </annotationProcessorPaths>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.moditect</groupId>
            <artifactId>moditect-maven-plugin</artifactId>
            <version>1.0.0.Beta2</version>
            <executions>
                <execution>
                    <id>generate-module-info</id>
                    <phase>generate-sources</phase>
                    <goals>
                        <goal>generate-module-info</goal>
                    </goals>
                    <configuration>
                        <modules>
                            <module>
                                <artifact>
                                    <groupId>com.google.auto.value</groupId>
                                    <artifactId>auto-value-annotations</artifactId>
                                    <version>${auto-value.version}</version>
                                </artifact>
                                <moduleInfo>
                                    <name>com.google.auto.value.annotations</name>
                                    <exports>
                                        com.google.auto.value;
                                        *;
                                    </exports>
                                </moduleInfo>
                            </module>
                        </modules>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

<properties>
    <maven.compiler.source>13</maven.compiler.source>
    <maven.compiler.target>13</maven.compiler.target>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <auto-value.version>1.7</auto-value.version>
</properties>

The important portion is the moditect-maven-plugin configuration. Since I need the com.google.auto.value.AutoValue annotation, I export that package and then give a relevant name to the module.

Just for reference, here's the class I'm using the annotation in:

package com.example.moditect.test;

import com.google.auto.value.AutoValue;

@AutoValue
abstract class Animal {

    abstract String name();
    abstract int numberOfLegs();

    static Builder builder() {
        return new AutoValue_Animal.Builder();
    }

    @AutoValue.Builder
    abstract static class Builder {
        abstract Builder setName(String value);
        abstract Builder setNumberOfLegs(int value);
        abstract Animal build();
    }
}

...and here's the module-info.java file of my application:

module com.example.moditect.test {
    requires com.google.auto.value.annotations;
}

However, when I run mvn clean install, I get the module not found error:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.1:compile (default-compile) on project moditect-test: Compilation failure
[ERROR] /home/someuser/development/workspace/moditect-test/src/main/java/module-info.java:[2,35] module not found: com.google.auto.value.annotations

It does appear that the moditect-maven-plugin is working based on these logs that get outputted when I run mvn clean install:

[INFO] --- moditect-maven-plugin:1.0.0.Beta2:generate-module-info (generate-module-info) @ moditect-test ---
writing to /home/someuser/development/workspace/moditect-test/target/moditect/auto.value.annotations/module-info.java
[INFO] Created module descriptor at /home/someuser/development/workspace/moditect-test/target/generated-sources/modules/com.google.auto.value.annotations/module-info.java

And for what it's worth, here's the generated module-info of this auto-value library (from the location that's logged above):

module com.google.auto.value.annotations {
    exports com.google.auto.value;
    exports com.google.auto.value.extension.memoized;
}

So I need some help figuring out what I did wrong. I'm assuming I just messed up the configuration of the moditect-maven-plugin, but I'm not sure how.

Answer 1

I made the silly mistake of using the goal generate-module-info instead of add-module-info. Just switching the goal with the correct one solved this issue.