The Android Gradle Plugin

This page describes how to build the Android Gradle plugin, and to test it.

Get the Source Code

Follow the instructions here to checkout the source code.

Once you have checked out the source code, the Gradle Plugin code can be found under tools/base

Building and editing the Android Gradle plugin

To edit the plugin import the Gradle project rooted in the tools directory in to the most recent Intellij IDEA EAP.

You can run unit and integration tests directly from within Intellij IDEA. You can also run them with Gradle from the command line

To build AGP for use in other projects, use the “Execute Gradle Task” action to run :publishAndroidGradleLocal (or :publishLocal if you also need the databinding libraries)

The above command publishes the plugin to a local Maven repository located in ../out/repo/, and it is also done as part of running the integration tests.

Debugging the Android Gradle plugin

To debug unit tests simply use the debug action in Intellij IDEA.

To debug the Android Gradle Plugin being run from integration tests:

1. Add the environment variable DEBUG_INNER_TEST=1 to the run configuration
2. Run the test in IDEA (Run, not debug, unless you want to debug both the test and the plugin at the same time)
3. Connect the Intellij remote debugger to port 5006

Using locally built plugin in a project

To test your own Gradle projects using your modified Android Gradle plugin, modify the settings.gradle{.kts} file to point to your local repository (where the above :publishLocal task installed your build). For example, if you ran the repo init command above in /my/aosp/work then the repository will be in /my/aosp/work/out/repo.

You will also need to change the AGP version referenced. You can find the version number of your locally built AGP by looking at the directory that was created in /my/aosp/work/out/repo/com/android/tools/build/gradle/ when you ran the :publishLocal task. The version number will end in -dev (e.g. 8.4.0-dev), unless you run gradle with -Prelease=true, in which case it will use the release suffix (e.g. 8.4.0-alpha01).

// settings.gradle (Groovy DSL)
pluginManagement {
    repositories {
        // Begin change: Add local Maven repo.
        maven { url '/my/aosp/work/out/repo' }
        // End change.
        gradlePluginPortal()
        google()
        mavenCentral()
    }
    dependencies {
        // Begin change: update AGP version.
        classpath 'com.android.tools.build:gradle:8.4.0-dev'
        // End change.
    }
}

dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
        // Begin change: Add local Maven repo.
        maven { url '/my/aosp/work/out/repo' }
        // End change.
        google()
        mavenCentral()
    }
}

If your project does not have a pluginManagement or dependencyResolutionManagement block in settings.gradle, look in build.gradle for a buildscript or allProjects block, respectively, and make the changes there instead.

// settings.gradle.kts (Kotlin DSL)
pluginManagement {
    repositories {
        // Begin change: Add local Maven repo.
        maven(url = "/my/aosp/work/out/repo")
        // End change.
        google()
        mavenCentral()
        gradlePluginPortal()
    }
}
dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
        // Begin change: Add local Maven repo.
        maven(url = "/my/aosp/work/out/repo")
        // End change.
        google()
        mavenCentral()
    }
}

In recent projects, the AGP version will usually be in gradle/libs.versions.toml, but it could also be in the root build.gradle.kts.

Debugging

To debug a project like this simply run

$ ./gradlew --no-daemon -Dorg.gradle.debug=true someTask

and connect a remote debugger to port 5005.

Preparing your changes for submission

If you‘ve made changes, make sure you run the tests to ensure you haven’t broken anything:

cd base/build-system && ../../gradlew test

Presubmit runs all the tests, so another strategy is to guess which tests may be affected by your change and run them locally but rely on the presubmit tests to run all the integration tests.