Android on Nix

This repo summarizes my several attempts at packaging android applications as nix flakes:

• sphinx-style: replicating the androsphinx nix flake, that uses a fork of gradle2nix
• statsim-style: replicating the nix workflow at status-im
• tadfisher-style: replicating this gist by tadfisher

All attempts were unsuccessful with semi-complex application configurations that use any of the following:

• subprojects
• gradle build configurations
• buildscript dependencies
• custom maven repositories (tend to lack a maven-metadata.xml)

Conversations.im specific nits

The Conversations application vendors in libwebrtc because it is not provided as a consumable library via a maven repository. Build instructions suggest downloading the .aar file and placing it inside /libs. To side step this, make use of the following patch that fetches libwebrtc from an unofficial maven repo:

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>     maven {
>         url 'https://raw.github.com/abdularis/libwebrtc-android/repo/'
>     }
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>     implementation 'com.aar.app:google-webrtc:M83'
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<     implementation fileTree(include: ['libwebrtc-m90.aar'], dir: 'libs')
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< 

Entering a nix-shell with the android sdk and gradle should now allow you to build the application with:

./gradlew assembleConversationsFreeSystemDebug

General notes

• all project sources are loaded from local directories, a local copy of build.gradle is required to run any form of gradle locking + SHA calculation
• gradle v7 has an internal lock mechanism but unlike tools like cargo or yarn, lock files aren't as useful because gradle further resolves these dependencies into "artifacts". Additionally, gradle gives projects the ability to modify this resolution process (resolution strategies, dependency substitution, module replacement), making it pretty complex to replicate in nix
• there exists a androidenv.buildApp in nixpkgs, this works only for ANT based android projects. The utility to convert gradle projects to ANT android projects has been deprecated by google