Move binding coroutine implementation to separate subproject

README.md

@@ -136,6 +136,36 @@ resources on the topic of monad comprehensions.
 - [Monad comprehensions - Bow (Swift)][bow-monad-comprehension]
 - [For comprehensions - Scala][scala-for-comprehension]
 
+#### Coroutine Support
+
+Use of coroutines within a `binding` block requires an additional dependency:
+
+```kotlin
+dependencies {
+    implementation("com.michael-bull.kotlin-result:kotlin-result:1.1.8")
+    implementation("com.michael-bull.kotlin-result:kotlin-result-coroutines:1.1.8")
+}
+```
+
+This allows for asynchronous binds to operate so that if a bind were to fail,
+the binding block will return with the first failing async result:
+
+```kotlin
+
+suspend fun failsIn5ms(): Result<Int, DomainErrorA> { ... }
+suspend fun failsIn1ms(): Result<Int, DomainErrorB> { ... }
+
+runBlocking{
+    val result = binding<Int, BindingError> {
+        val x = async { failsIn5ms().bind() }
+        val y = async { failsIn1ms().bind() }
+        x.await() + y.await()
+    }
+
+    // result will be Err(DomainErrorB)
+}
+```
+
 ## Inspiration
 
 Inspiration for this library has been drawn from other languages in which the

build.gradle.kts

@@ -1,5 +1,7 @@
 import com.github.benmanes.gradle.versions.updates.DependencyUpdatesTask
 import org.jetbrains.dokka.gradle.DokkaTask
+import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformExtension
+import org.jetbrains.kotlin.gradle.plugin.KotlinMultiplatformPluginWrapper
 
 val ossrhUsername: String? by ext
 val ossrhPassword: String? by ext
@@ -7,14 +9,14 @@ val ossrhPassword: String? by ext
 description = "A Result monad for modelling success or failure operations."
 
 plugins {
-    `maven-publish`
-    signing
-    kotlin("multiplatform") version "1.3.72"
-    id("org.jetbrains.dokka") version "0.10.1"
+    base
     id("com.github.ben-manes.versions") version "0.28.0"
-    id("net.researchgate.release") version "2.8.1"
-    id("kotlinx.benchmark") version "0.2.0-dev-8"
-    id("org.jetbrains.kotlin.plugin.allopen") version "1.3.72"
+
+    kotlin("multiplatform") version "1.3.72" apply false
+    id("kotlinx.benchmark") version "0.2.0-dev-8" apply false
+    id("net.researchgate.release") version "2.8.1" apply false
+    id("org.jetbrains.dokka") version "0.10.1" apply false
+    id("org.jetbrains.kotlin.plugin.allopen") version "1.3.72" apply false
 }
 
 tasks.withType<DependencyUpdatesTask> {
@@ -25,6 +27,29 @@ tasks.withType<DependencyUpdatesTask> {
     }
 }
 
+allprojects {
+    repositories {
+        mavenCentral()
+        jcenter()
+        maven("https://dl.bintray.com/kotlin/kotlinx")
+    }
+}
+
+subprojects {
+    plugins.withType<MavenPublishPlugin> {
+        apply(plugin = "net.researchgate.release")
+        apply(plugin = "org.gradle.signing")
+
+        val afterReleaseBuild by tasks.existing(DefaultTask::class)
+        val publish by tasks.existing(Task::class)
+
+        afterReleaseBuild {
+            dependsOn(publish)
+        }
+
+        plugins.withType<KotlinMultiplatformPluginWrapper> {
+            apply(plugin = "org.jetbrains.dokka")
+
             val dokka by tasks.existing(DokkaTask::class) {
                 outputFormat = "javadoc"
                 outputDirectory = "$buildDir/docs/javadoc"
@@ -38,86 +63,16 @@ val javadocJar by tasks.registering(Jar::class) {
                 from(dokka.get().outputDirectory)
             }
 
-allprojects {
-    repositories {
-        mavenCentral()
-        jcenter()
-        maven("https://dl.bintray.com/kotlin/kotlinx")
-    }
-}
-
-allOpen {
-    annotation("org.openjdk.jmh.annotations.State")
-    annotation("org.openjdk.jmh.annotations.BenchmarkMode")
-}
-
-sourceSets.create("benchmark")
-
-benchmark {
-    targets {
-        register("jvmBenchmark")
-    }
-}
-
-kotlin {
+            configure<KotlinMultiplatformExtension> {
                 jvm {
-        withJava()
-
                     mavenPublication {
                         artifact(javadocJar.get())
                     }
-
-        compilations.all {
-            kotlinOptions {
-                jvmTarget = "1.8"
                 }
             }
         }
 
-    sourceSets {
-        all {
-            languageSettings.apply {
-                useExperimentalAnnotation("kotlin.contracts.ExperimentalContracts")
-            }
-        }
-
-        val commonMain by getting {
-            dependencies {
-                implementation(kotlin("stdlib-common"))
-            }
-        }
-
-        val commonTest by getting {
-            dependencies {
-                implementation(kotlin("test-common"))
-                implementation(kotlin("test-annotations-common"))
-                implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core-native:1.3.7")
-            }
-        }
-
-        val jvmMain by getting {
-            dependencies {
-                implementation(kotlin("stdlib-jdk8"))
-            }
-        }
-
-        val jvmTest by getting {
-            dependencies {
-                implementation(kotlin("test-junit"))
-                implementation(kotlin("test"))
-            }
-        }
-
-        val jvmBenchmark by getting {
-            dependsOn(jvmMain)
-            dependencies {
-                implementation("org.jetbrains.kotlinx:kotlinx.benchmark.runtime-jvm:0.2.0-dev-8")
-            }
-        }
-    }
-}
-
-publishing {
+        configure<PublishingExtension> {
             repositories {
                 maven {
                     if (project.version.toString().endsWith("SNAPSHOT")) {
@@ -188,13 +143,11 @@ publishing {
                     }
                 }
             }
-}
 
-signing {
+            configure<SigningExtension> {
                 useGpgCmd()
-    sign(publishing.publications)
+                sign(publications)
+            }
+        }
     }
-
-tasks.afterReleaseBuild {
-    dependsOn(tasks.publish)
 }

example/build.gradle.kts

@@ -17,7 +17,7 @@ repositories {
 dependencies {
     val ktorVersion = "1.3.2"
 
-    implementation(rootProject)
+    implementation(project(":kotlin-result"))
     implementation(kotlin("stdlib-jdk8"))
     implementation("ch.qos.logback:logback-classic:1.2.3")
     implementation("io.ktor:ktor-server-core:$ktorVersion")

kotlin-result-coroutines/build.gradle.kts

@@ -0,0 +1,41 @@
+description = "Extensions for using kotlin-result with kotlinx-coroutines."
+
+plugins {
+    `maven-publish`
+    kotlin("multiplatform")
+}
+
+kotlin {
+    sourceSets {
+        all {
+            languageSettings.apply {
+                useExperimentalAnnotation("kotlin.contracts.ExperimentalContracts")
+            }
+        }
+
+        val commonMain by getting {
+            dependencies {
+                implementation(kotlin("stdlib-common"))
+                implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core-native:1.3.8")
+                implementation(project(":kotlin-result"))
+            }
+        }
+
+        val commonTest by getting {
+            dependencies {
+                implementation(kotlin("test-common"))
+                implementation(kotlin("test-annotations-common"))
+                implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core-native:1.3.8")
+            }
+        }
+
+        val jvmTest by getting {
+            dependencies {
+                implementation(kotlin("test-junit"))
+                implementation(kotlin("test"))
+                implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.8")
+            }
+        }
+    }
+}
+

kotlin-result-coroutines/src/commonMain/kotlin/com/github/michaelbull/result/coroutines/binding/SuspendableBinding.kt

@@ -0,0 +1,54 @@
+package com.github.michaelbull.result.coroutines.binding
+
+import com.github.michaelbull.result.Err
+import com.github.michaelbull.result.Ok
+import com.github.michaelbull.result.Result
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import kotlin.contracts.InvocationKind
+import kotlin.contracts.contract
+
+/**
+ * Suspending variant of [binding][com.github.michaelbull.result.binding].
+ */
+suspend inline fun <V, E> binding(crossinline block: suspend SuspendableResultBinding<E>.() -> V): Result<V, E> {
+    contract {
+        callsInPlace(block, InvocationKind.EXACTLY_ONCE)
+    }
+
+    val receiver = SuspendableResultBindingImpl<E>()
+
+    return try {
+        with(receiver) { Ok(block()) }
+    } catch (ex: BindCancellationException) {
+        receiver.internalError
+    }
+}
+
+internal object BindCancellationException : CancellationException(null)
+
+interface SuspendableResultBinding<E> {
+    suspend fun <V> Result<V, E>.bind(): V
+}
+
+@PublishedApi
+internal class SuspendableResultBindingImpl<E> : SuspendableResultBinding<E> {
+
+    private val mutex = Mutex()
+    lateinit var internalError: Err<E>
+
+    override suspend fun <V> Result<V, E>.bind(): V {
+        return when (this) {
+            is Ok -> value
+            is Err -> {
+                mutex.withLock {
+                    if (::internalError.isInitialized.not()){
+                        internalError = this
+                    }
+                }
+                throw BindCancellationException
+            }
+        }
+    }
+}

kotlin-result-coroutines/src/commonTest/kotlin/com.github.michaelbull.result.coroutines/RunBlockingTest.kt

@@ -1,4 +1,4 @@
-package com.github.michaelbull.result
+package com.github.michaelbull.result.coroutines
 
 import kotlinx.coroutines.CoroutineScope
 

kotlin-result-coroutines/src/commonTest/kotlin/com.github.michaelbull.result.coroutines/binding/SuspendableBindingTest.kt

@@ -1,9 +1,9 @@
-package com.github.michaelbull.result.coroutines
+package com.github.michaelbull.result.coroutines.binding
 
 import com.github.michaelbull.result.Err
 import com.github.michaelbull.result.Ok
 import com.github.michaelbull.result.Result
-import com.github.michaelbull.result.runBlockingTest
+import com.github.michaelbull.result.coroutines.runBlockingTest
 import kotlinx.coroutines.delay
 import kotlin.test.Test
 import kotlin.test.assertEquals

kotlin-result-coroutines/src/jvmTest/kotlin/com/github/michaelbull/result/coroutines/RunBlockingTest.kt

@@ -1,4 +1,4 @@
-package com.github.michaelbull.result
+package com.github.michaelbull.result.coroutines
 
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.runBlocking

kotlin-result-coroutines/src/jvmTest/kotlin/com/github/michaelbull/result/coroutines/binding/AsyncSuspendableBindingTest.kt

@@ -0,0 +1,79 @@
+package com.github.michaelbull.result.coroutines.binding
+
+import com.github.michaelbull.result.Err
+import com.github.michaelbull.result.Ok
+import com.github.michaelbull.result.Result
+import kotlinx.coroutines.async
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.runBlocking
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class AsyncSuspendableBindingTest {
+
+    private sealed class BindingError {
+        object BindingErrorA : BindingError()
+        object BindingErrorB : BindingError()
+    }
+
+    @Test
+    fun returnsOkIfAllBindsSuccessful() {
+        suspend fun provideX(): Result<Int, BindingError> {
+            delay(100)
+            return Ok(1)
+        }
+
+        suspend fun provideY(): Result<Int, BindingError> {
+            delay(100)
+            return Ok(2)
+        }
+
+        runBlocking {
+            val result = binding<Int, BindingError> {
+                val x = async { provideX().bind() }
+                val y = async { provideY().bind() }
+                x.await() + y.await()
+            }
+
+            assertTrue(result is Ok)
+            assertEquals(
+                expected = 3,
+                actual = result.value
+            )
+        }
+    }
+
+    @Test
+    fun returnsFirstErrIfBindingFailed() {
+        suspend fun provideX(): Result<Int, BindingError> {
+            delay(1)
+            return Ok(1)
+        }
+
+        suspend fun provideY(): Result<Int, BindingError.BindingErrorA> {
+            delay(2)
+            return Err(BindingError.BindingErrorA)
+        }
+
+        suspend fun provideZ(): Result<Int, BindingError.BindingErrorB> {
+            delay(1)
+            return Err(BindingError.BindingErrorB)
+        }
+
+        runBlocking {
+            val result = binding<Int, BindingError> {
+                val x = async { provideX().bind() }
+                val y = async { provideY().bind() }
+                val z = async { provideZ().bind() }
+                x.await() + y.await() + z.await()
+            }
+
+            assertTrue(result is Err)
+            assertEquals(
+                expected = BindingError.BindingErrorB,
+                actual = result.error
+            )
+        }
+    }
+}

kotlin-result/build.gradle.kts

@@ -0,0 +1,75 @@
+description = "A Result monad for modelling success or failure operations."
+
+plugins {
+    `maven-publish`
+    kotlin("multiplatform")
+    id("org.jetbrains.kotlin.plugin.allopen")
+    id("kotlinx.benchmark")
+}
+
+allOpen {
+    annotation("org.openjdk.jmh.annotations.State")
+    annotation("org.openjdk.jmh.annotations.BenchmarkMode")
+}
+
+sourceSets.create("benchmark")
+
+benchmark {
+    targets {
+        register("jvmBenchmark")
+    }
+}
+
+kotlin {
+    jvm {
+        withJava()
+
+        compilations.all {
+            kotlinOptions {
+                jvmTarget = "1.8"
+            }
+        }
+    }
+
+    sourceSets {
+        all {
+            languageSettings.apply {
+                useExperimentalAnnotation("kotlin.contracts.ExperimentalContracts")
+            }
+        }
+
+        val commonMain by getting {
+            dependencies {
+                implementation(kotlin("stdlib-common"))
+            }
+        }
+
+        val commonTest by getting {
+            dependencies {
+                implementation(kotlin("test-common"))
+                implementation(kotlin("test-annotations-common"))
+            }
+        }
+
+        val jvmMain by getting {
+            dependencies {
+                implementation(kotlin("stdlib-jdk8"))
+            }
+        }
+
+        val jvmTest by getting {
+            dependencies {
+                implementation(kotlin("test-junit"))
+                implementation(kotlin("test"))
+            }
+        }
+
+        val jvmBenchmark by getting {
+            dependsOn(jvmMain)
+            dependencies {
+                implementation("org.jetbrains.kotlinx:kotlinx.benchmark.runtime-jvm:0.2.0-dev-8")
+            }
+        }
+    }
+}
+

kotlin-result/src/commonMain/kotlin/com/github/michaelbull/result/coroutines/SuspendableBinding.kt

@@ -11,6 +11,12 @@ import kotlin.contracts.contract
 /**
  * Suspending variant of [binding][com.github.michaelbull.result.binding].
  */
+@Deprecated(
+    message = "Will throw a runtime exception if used with async requests that fail to bind. " +
+        "See https://github.com/michaelbull/kotlin-result/pull/28 " +
+        "Please import the kotlin-result-coroutines library to continue using this feature.",
+    level = DeprecationLevel.WARNING
+)
 suspend inline fun <V, E> binding(crossinline block: suspend ResultBinding<E>.() -> V): Result<V, E> {
     contract {
         callsInPlace(block, InvocationKind.EXACTLY_ONCE)

settings.gradle.kts

@@ -1,6 +1,10 @@
 rootProject.name = "kotlin-result"
 
-include("example")
+include(
+    "example",
+    "kotlin-result",
+    "kotlin-result-coroutines"
+)
 
 pluginManagement {
     repositories {