devinmorgan / shadow-plugin-for-aar

This represents an example Gradle Plugin that uses the Shadow Plugin to relocate the JAR within an AAR to an arbitrary package namepsace to avoid collisions with library consumers

Motivation

The Gradle Shadow Plugin is a very useful plugin for allowing Java library authors to relocate packages from their original namespace to a new package namespace to avoid collisions between a library’s dependencies and a host application’s dependencies. Android library authors face the same concerns as Java library authors. However, the Gradle Shadow Plugin does not work out of the box for Android Artifacts (AARs) - the artifact format of Android Libraries - as the Gradle Shadow Plugin is only designed to work with Java Artifacts (JARs) out of the box. This repo defines an example Gradle Plugin called the ShadowAarDependenciesPlugin that provides Android library authors with an easy way for declaring Android Artifact dependencies in need of namespace relocations.

Getting started

Step 1

In your app/build.gradle.kts, make sure to import the ShadowAarDependenciesPlugin plugin and the ShadowAarDependenciesPluginExtension extension.

import com.example.ShadowAarDependenciesPlugin
import com.example.ShadowAarDependenciesPluginExtension

Step 2

You’ll then need apply the ShadowAarDependenciesPlugin plugin

apply<ShadowAarDependenciesPlugin>()

Step 3

Next, declare all of the package namespace relocations you are looking to perform in the extension

extensions.getByType(ShadowAarDependenciesPluginExtension::class.java).apply {
    relocations.set(mutableListOf(
        listOf("com.original.namespaceA", "com.new.namespaceA"),
        listOf("com.original.namespaceB", "com.new.namespaceB"),
    ))
}

Step 4

Finally, declare all of the Android Artifact dependencies that require namespace relocation in the aarImplementation configuration. The aarImplementation configuration will put the relocated packages on both the compile time classpath and the runtime classpath.

dependencies {
    add("aarImplementation", "com.datadoghq:dd-sdk-android-logs:2.2.0")
}

How does it work?

As we’ve already established, The Gradle Shadow Plugin operates out of the box on Java Artifacts (JARs) and is not capable of operating on Android Artifacts (AARs). However, Android Artifacts are typically just zip files that contain a classes.jar, which is the library’s compiled JVM code. This plugin bridges the gap by creating a special Gradle configuration for declaring AAR dependencies (there’s no need to do this for JAR libraries as you can just use the Gradle Shadow Plugin’s ShadowJar task directly), fetches the AAR artifacts from the remote repository, unzips the AARs, extracts the classes.jar, passes these extracted JARs to a ShadowJar task to perform namespace relocation, and finally puts these relocated JARs back into the standard implementation configuration.

graph TB
    A[Start: Declare AAR Dependencies in Special Configuration] --> B[Fetch AAR Artifacts]
    B --> C[Unzip AARs]
    C --> D[Extract classes.jar]
    D --> E[Pass JARs to ShadowJar Task]
    E --> F[Perform Namespace Relocation]
    F --> G[Put Relocated JARs into implementation Configuration]
    J[Declare JAR Dependencies] -.-> E

    style A fill:#f9d6d2
    style B fill:#f9e5d2
    style C fill:#f9f3d2
    style D fill:#eaf9d2
    style E fill:#d2f9d7

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shadow-plugin-for-aar's Issues

Issue with duplicate .properties file

Having some issue using this solution on a library that contain .properties file. I have the impression that using mergeServiceFiles() would solve the issue.

Plugin is worked?

I tried to use your plugin, but I had problems losing annotations, duplicating classes using the example of the Room library

Example

Duplicate class ru.analytics.test.room.TypeConverters found in modules jetified-analytics (analytics.jar) and jetified-app (app.jar) Duplicate class ru.analytics.test.room.Update found in modules jetified-analytics (analytics.jar) and jetified-app (app.jar) Duplicate class ru.analytics.test.room.Upsert found in modules jetified-analytics (analytics.jar) and jetified-app (app.jar) Duplicate class ru.analytics.test.room.migration.AutoMigrationSpec found in modules jetified-analytics (analytics.jar) and jetified-app (app.jar) Duplicate class ru.analytics.test.room.migration.Migration found in modules jetified-analytics (analytics.jar) and jetified-app (app.jar) Duplicate class ru.analytics.test.room.migration.MigrationImpl found in modules jetified-analytics (analytics.jar) and jetified-app (app.jar) Duplicate class ru.analytics.test.room.migration.MigrationKt found in modules jetified-analytics (analytics.jar) and jetified-app (app.jar) Duplicate class ru.analytics.test.room.paging.LimitOffsetDataSource found in modules jetified-analytics (analytics.jar) and jetified-app (app.jar) Duplicate class ru.analytics.test.room.paging.LimitOffsetDataSource$1 found in modules jetified-analytics (analytics.jar) and jetified-app (app.jar) Duplicate class ru.analytics.test.room.util.CursorUtil found in modules jetified-analytics (analytics.jar) and jetified-app (app.jar)

Annotations also disappear in generated files.
C:\Project\analytics-sdk\analytics\build\tmp\kapt3\stubs\googleDebug\ru\analytics\sdk\session\data\dao\SessionWithRemovedEventDao.java:23: error: incompatible types: NonExistentClass cannot be converted to Annotation @error.NonExistentClass ^
For method
@org.jetbrains.annotations.Nullable @error.NonExistentClass public abstract java.lang.Object insert(@org.jetbrains.annotations.NotNull ru.analytics.sdk.session.data.entities.SessionWithRemovedEventEntity session, @org.jetbrains.annotations.NotNull kotlin.coroutines.Continuation<? super kotlin.Unit> continuation);

how I use it

`shadowAarPlugin {
relocations.value(
        [["androidx", "ru.analytics.test"]]
)

}
`

It seems to me that your solution is not working