From 1eae2382eed362484d8c2f22e7dc3c6e7e22c5dd Mon Sep 17 00:00:00 2001
From: Vsevolod Tolstopyatov <qwwdfsad@gmail.com>
Date: Fri, 6 Mar 2020 18:25:37 +0300
Subject: [PATCH] Make call to service loader in reactor integrations
 optimizable by R8 (#1847)

Fixes #1817
---
 reactive/kotlinx-coroutines-reactive/src/Await.kt      | 10 ----------
 .../kotlinx-coroutines-reactive/src/ReactiveFlow.kt    |  9 +++++----
 ui/kotlinx-coroutines-android/build.gradle             |  4 ++--
 .../test/R8ServiceLoaderOptimizationTest.kt            |  6 +++---
 4 files changed, 10 insertions(+), 19 deletions(-)

diff --git a/reactive/kotlinx-coroutines-reactive/src/Await.kt b/reactive/kotlinx-coroutines-reactive/src/Await.kt
index 317baab5f5..9ea2e3c50e 100644
--- a/reactive/kotlinx-coroutines-reactive/src/Await.kt
+++ b/reactive/kotlinx-coroutines-reactive/src/Await.kt
@@ -82,16 +82,6 @@ public suspend fun <T> Publisher<T>.awaitSingle(): T = awaitOne(Mode.SINGLE)
 
 // ------------------------ private ------------------------
 
-// ContextInjector service is implemented in `kotlinx-coroutines-reactor` module only.
-// If `kotlinx-coroutines-reactor` module is not included, the list is empty.
-private val contextInjectors: Array<ContextInjector> =
-    ServiceLoader.load(ContextInjector::class.java, ContextInjector::class.java.classLoader).iterator().asSequence().toList().toTypedArray() // R8 opto
-
-private fun <T> Publisher<T>.injectCoroutineContext(coroutineContext: CoroutineContext) =
-    contextInjectors.fold(this) { pub, contextInjector ->
-        contextInjector.injectCoroutineContext(pub, coroutineContext)
-    }
-
 private enum class Mode(val s: String) {
     FIRST("awaitFirst"),
     FIRST_OR_DEFAULT("awaitFirstOrDefault"),
diff --git a/reactive/kotlinx-coroutines-reactive/src/ReactiveFlow.kt b/reactive/kotlinx-coroutines-reactive/src/ReactiveFlow.kt
index 3a81c0696d..20e165e705 100644
--- a/reactive/kotlinx-coroutines-reactive/src/ReactiveFlow.kt
+++ b/reactive/kotlinx-coroutines-reactive/src/ReactiveFlow.kt
@@ -140,13 +140,14 @@ private class ReactiveSubscriber<T : Any>(
 
 // ContextInjector service is implemented in `kotlinx-coroutines-reactor` module only.
 // If `kotlinx-coroutines-reactor` module is not included, the list is empty.
-private val contextInjectors: List<ContextInjector> =
-    ServiceLoader.load(ContextInjector::class.java, ContextInjector::class.java.classLoader).toList()
+private val contextInjectors: Array<ContextInjector> =
+    ServiceLoader.load(ContextInjector::class.java, ContextInjector::class.java.classLoader)
+        .iterator().asSequence()
+        .toList().toTypedArray() // R8 opto
 
-private fun <T> Publisher<T>.injectCoroutineContext(coroutineContext: CoroutineContext) =
+internal fun <T> Publisher<T>.injectCoroutineContext(coroutineContext: CoroutineContext) =
     contextInjectors.fold(this) { pub, contextInjector -> contextInjector.injectCoroutineContext(pub, coroutineContext) }
 
-
 /**
  * Adapter that transforms [Flow] into TCK-complaint [Publisher].
  * [cancel] invocation cancels the original flow.
diff --git a/ui/kotlinx-coroutines-android/build.gradle b/ui/kotlinx-coroutines-android/build.gradle
index 68e2232cf2..51702cdbe3 100644
--- a/ui/kotlinx-coroutines-android/build.gradle
+++ b/ui/kotlinx-coroutines-android/build.gradle
@@ -77,7 +77,7 @@ task runR8(type: RunR8Task, dependsOn: 'jar'){
     inputConfig = file('testdata/r8-test-rules.pro')
 }
 
-task runR8NoOptim(type: RunR8Task, dependsOn: 'jar'){
+task runR8NoOptim(type: RunR8Task, dependsOn: 'jar') {
     outputDex = unOptimizedDexDir
     inputConfig = file('testdata/r8-test-rules-no-optim.pro')
 }
@@ -103,4 +103,4 @@ tasks.withType(dokka.getClass()) {
         url = new URL("https://developer.android.com/reference/")
         packageListUrl = projectDir.toPath().resolve("package.list").toUri().toURL()
     }
-}
\ No newline at end of file
+}
diff --git a/ui/kotlinx-coroutines-android/test/R8ServiceLoaderOptimizationTest.kt b/ui/kotlinx-coroutines-android/test/R8ServiceLoaderOptimizationTest.kt
index 7f03378d00..47beb85bbf 100644
--- a/ui/kotlinx-coroutines-android/test/R8ServiceLoaderOptimizationTest.kt
+++ b/ui/kotlinx-coroutines-android/test/R8ServiceLoaderOptimizationTest.kt
@@ -16,7 +16,7 @@ class R8ServiceLoaderOptimizationTest : TestBase() {
     private val r8DexNoOptim = File(System.getProperty("noOptimDexPath")!!).asDexFile()
 
     @Test
-    fun noServiceLoaderCalls() {
+    fun testNoServiceLoaderCalls() {
         val serviceLoaderInvocations = r8Dex.types.any {
             it.type == "Ljava/util/ServiceLoader;"
         }
@@ -28,7 +28,7 @@ class R8ServiceLoaderOptimizationTest : TestBase() {
     }
 
     @Test
-    fun androidDispatcherIsKept() {
+    fun testAndroidDispatcherIsKept() {
         val hasAndroidDispatcher = r8DexNoOptim.classes.any {
             it.type == "Lkotlinx/coroutines/android/AndroidDispatcherFactory;"
         }
@@ -38,7 +38,7 @@ class R8ServiceLoaderOptimizationTest : TestBase() {
 
     @Test
     @Ignore
-    fun noOptimRulesMatch() {
+    fun testNoOptimRulesMatch() {
         val paths = listOf(
                 "META-INF/com.android.tools/proguard/coroutines.pro",
                 "META-INF/proguard/coroutines.pro",