From 399da799a66af60df3175808eae98d08c5fcae06 Mon Sep 17 00:00:00 2001
From: Siddarth Kumar <siddarthkay@gmail.com>
Date: Sat, 23 Mar 2024 15:12:05 +0530
Subject: [PATCH] speed up android debug builds (#19335)

fixes #19081

## Summary
This PR aims to improve android build step for debug variants by ensuring we do not rebuild the android derivation for any change made to `clojurescript` code.

We also do the following things :
-  enable `JVM` parallel garbage collector.
-  get rid of `dexOptions` which was deprecated in `gradle 8`.
-  add additional `parallel` flag to `gradle` to speed up builds.

## Review notes
- `make run-clojure`
- `make run-android`
- ctrl + C on android terminal and edit any `cljs` file
- `make run-android`  ( should build almost instantly )
---
 android/app/build.gradle     |  4 ----
 android/build.gradle         | 17 +++++++++++++++++
 android/gradle.properties    |  2 +-
 nix/mobile/android/build.nix |  6 +++++-
 4 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/android/app/build.gradle b/android/app/build.gradle
index 3e21fe6dc8..b7b7d05bb4 100644
--- a/android/app/build.gradle
+++ b/android/app/build.gradle
@@ -199,10 +199,6 @@ android {
         doNotStrip '*/mips/*.so'
         doNotStrip '*/mips64/*.so'
     }
-    dexOptions {
-        jumboMode true
-        javaMaxHeapSize "8g"
-    }
     splits {
         abi {
             reset()
diff --git a/android/build.gradle b/android/build.gradle
index 37b2240dc4..17890dface 100644
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -44,6 +44,23 @@ subprojects {
                 defaultConfig {
                     targetSdkVersion rootProject.ext.targetSdkVersion
                 }
+
+                // Speed up Tests Stage
+                tasks.withType(Test).configureEach {
+                    // https://docs.gradle.org/current/userguide/performance.html#execute_tests_in_parallel
+                    maxParallelForks = Runtime.runtime.availableProcessors().intdiv(2) ?: 1
+                    // https://docs.gradle.org/current/userguide/performance.html#fork_tests_into_multiple_processes
+                    forkEvery = 100
+                    // https://docs.gradle.org/current/userguide/performance.html#disable_reports
+                    reports.html.required = false
+                    reports.junitXml.required = false
+                }
+                // Speed up Java Compile Stage
+                // https://docs.gradle.org/current/userguide/performance.html#run_the_compiler_as_a_separate_process
+                tasks.withType(JavaCompile).configureEach {
+                    options.fork = true
+                }
+
             }
         }
     }
diff --git a/android/gradle.properties b/android/gradle.properties
index d8b5ad4e6d..5fd5209294 100644
--- a/android/gradle.properties
+++ b/android/gradle.properties
@@ -43,7 +43,7 @@ ANDROID_ABI_SPLIT=false
 # Some platforms are excluded though
 ANDROID_ABI_INCLUDE=armeabi-v7a;arm64-v8a;x86;x86_64
 
-org.gradle.jvmargs=-Xmx8704M
+org.gradle.jvmargs=-Xmx8704M -XX:+UseParallelGC
 
 versionCode=9999
 commitHash=unknown
diff --git a/nix/mobile/android/build.nix b/nix/mobile/android/build.nix
index a11dba4509..0a89e92fb3 100644
--- a/nix/mobile/android/build.nix
+++ b/nix/mobile/android/build.nix
@@ -26,9 +26,10 @@
 
 let
   inherit (lib) toLower optionalString stringLength makeLibraryPath elem;
+  notDebug = (buildType != "debug");
 
   # Pass secretsFile for POKT_TOKEN to jsbundle build
-  builtJsBundle = jsbundle { inherit secretsFile; };
+  builtJsBundle = lib.optionals notDebug jsbundle { inherit secretsFile; };
 
   # Map ANDROID_ABI_INCLUDE to status-go targets
   androidAbiIncludeSplit = lib.splitString ";" androidAbiInclude;
@@ -119,8 +120,10 @@ in stdenv.mkDerivation rec {
     # Export all vars from .env file
     export $(cut -d= -f1 .env)
 
+    ${lib.optionalString notDebug ''
     # Symlink React Native entrypoint.
     cp -Lr ${builtJsBundle} ./result
+    ''}
 
     # Copy android/ directory
     mkdir -p ./android/build
@@ -153,6 +156,7 @@ in stdenv.mkDerivation rec {
       --no-scan \
       --no-watch-fs \
       --no-build-cache \
+      --parallel \
       -Dmaven.repo.local='${deps.gradle}' \
       assemble${gradleBuildType}
     '';