The problem of maven multi-layer dependency transfer

Multiple internal packages are merged and exported to the customer and contain dependencies;

For example, there is the following dependency tree:

internal.lib1
    -> internal.lib2
        -> dependency-A
        -> dependency-B
        -> dependency-C
    -> internal.lib3
        -> dependency-D
        -> dependency-E
        -> dependency-F

Only one jar package is delivered to the customer, namely: internal.lib1.jar

• Since lib2/lib3 is inconvenient to deploy to the central repository.
• Nor want to deliver three separate jar packages each time(internal.lib1.jar，internal.lib2.jar，internal.lib3.jar).

So, when I packed lib1, I unpacked lib2 and lib3 into the classes directory of lib1.
And in the pom of lib1, set lib2/lib3 to provided.
At this point, I can deliver a single jar(internal.lib1.jar) that includes both lib2 and lib3.

However, the dependencies of lib2 and lib3 are not perceived by the client because lib2 and lib3 are provided. Causes dependencies not to be passed.

Having said that, my core needs are: Based on the dependency tree above, I need to deliver only one jar (containing only the internal classes) and pass external dependencies.

Finally, when a client references the lib I provide, it should have a dependency tree like this:

customer-service
    ->internal.lib1(internal.lib2&internal.lib3)
        -> dependency-A
        -> dependency-B
        -> dependency-C
        -> dependency-D
        -> dependency-E
        -> dependency-F

Since I couldn't find a suitable existing solution, I wrote a maven plugin to do just that, which has been released to the central repository: gpom-maven-plugin
Use as follows:

<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>

    <version>1.0</version>
    <groupId>com.example</groupId>
    <artifactId>internal.lib3</artifactId>

    <dependencies>
        <dependency>
            <version>1.0</version>
            <groupId>com.example</groupId>
            <artifactId>internal.lib2</artifactId>
        </dependency>
        <dependency>
            <version>1.0</version>
            <groupId>com.example</groupId>
            <artifactId>internal.lib3</artifactId>
        </dependency>
        <dependency>
            <version>1.0</version>
            <groupId>com.external</groupId>
            <artifactId>dependency-C</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <executions>
                    <!--unpack lib1, and lib2 to lib3 classes-->
                    <execution>
                        <id>unpack-internal-dependencies</id>
                        <phase>prepare-package</phase>
                        <goals>
                            <goal>unpack-dependencies</goal>
                        </goals>
                        <configuration>
                            <includeGroupIds>com.example</includeGroupIds>
                            <excludes>**/META-INF/maven/**</excludes>
                            <outputDirectory>${project.build.outputDirectory}</outputDirectory>
                        </configuration>
                    </execution>
                    <!--output all dependencies of lib3 (including the dependency list of lib1 and lib2, but excluding lib1 and lib2 themselves) to the specified file-->
                    <execution>
                        <id>list-dependencies</id>
                        <phase>prepare-package</phase>
                        <goals>
                            <goal>list</goal>
                        </goals>
                        <configuration>
                            <excludeGroupIds>com.example</excludeGroupIds>
                            <outputFile>${project.build.directory}/dependencies</outputFile>
                            <silent>true</silent>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>io.github.kerwin612</groupId>
                <artifactId>gpom-maven-plugin</artifactId>
                <version>0.0.1</version>
                <executions>
                    <!--generate a new pom file based on the dependency file-->
                    <execution>
                        <phase>prepare-package</phase>
                        <goals>
                            <goal>generate</goal>
                        </goals>
                        <configuration>
                            <dependenciesPath>${project.build.directory}/dependencies</dependenciesPath>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <artifactId>maven-jar-plugin</artifactId>
                <executions>
                    <execution>
                        <id>default-jar</id>
                        <phase>none</phase>
                    </execution>
                    <execution>
                        <id>package-jar</id>
                        <goals>
                            <goal>jar</goal>
                        </goals>
                        <phase>package</phase>
                        <configuration>
                            <archive>
                                <!--use a specific pom file instead of the original pom file-->
                                <addMavenDescriptor>false</addMavenDescriptor>
                            </archive>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

For more information please see: https://github.com/kerwin612/gpom-maven-plugin