Soong-only

Generating the Android build graph includes a serial Kati stage. Kati processes Make build rules and generates the corresponding Ninja build rules.

LineageOS noted in its 23.2 release blog:

LineageOS is now nearly Android.mk free! Google announced their move from make to soong many years ago, pushing developers to migrate from Android.mk to Android.bp, and has started blocking Android.mk in many locations of the source tree.

However, some core build components still depend on Make, so Kati remains a required part of the build process.

uwuAOSP continues this migration by completing the final step, allowing modern devices to skip Kati's main build-graph generation stage. In our tests, this nearly halves build-graph generation time. Product configuration, such as BoardConfig, still uses Make; Soong-only does not mean that Makefiles cannot be used in the device tree.

Migrate a device

uwuAOSP has already handled most of the build components required for Soong-only on modern devices. Device bringup usually only requires migrating the following:

• uwu_kernel: replaces the legacy kernel build task;
• uwu_prebuilt_image: replaces $(call add-radio-file, ...) in the Make layer.

uwuCLI provides a migration script to simplify device bringup. After the script performs the mechanical conversion, review and validate the generated build rules.

To enable Soong-only temporarily, set the environment variable:

export SOONG_ONLY=true

You can also set it in the product configuration:

PRODUCT_SOONG_ONLY := true

NOTE

A-only devices depend on //bootable/deprecated-ota:updater, which has not yet been migrated. Soong-only cannot currently be used on these devices. If you need support for them, please open an issue in the issue tracker.

Validation

After migration, complete at least one full build and confirm that the device boots and its main functions work. Do not determine whether migration succeeded by checking against a fixed list of images.

The following devices have completed Soong-only build and boot validation:

• OnePlus 6T (fajita)
• OnePlus Ace 3 / 12R (aston(c))