Added a test that reproduces the plugin order problem.

Fixes #384

integration-testing/examples/plugin-order-bug/build.gradle

@@ -0,0 +1,52 @@
+buildscript {
+    repositories {
+        mavenLocal()
+        mavenCentral()
+    }
+
+    dependencies {
+        // If the order of adding atomicfu-gradle-plugin and kotlin-gradle-pluin to the classpath is changed, 
+        // then atomicfu dependency is not added to the classpath
+        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:${libs.versions.kotlinVersion.get()}")
+        classpath("org.jetbrains.kotlinx:atomicfu-gradle-plugin:${libs.versions.atomicfuVersion.get()}")
+        classpath("org.jetbrains.kotlin:atomicfu:${libs.versions.kotlinVersion.get()}")
+    }
+}
+
+apply plugin: 'org.jetbrains.kotlin.multiplatform'
+// The issue is described in #384. Application of kotlin-gradle-plugin by id fixes the compilation error.
+//plugins {
+//    id 'org.jetbrains.kotlin.multiplatform' version '1.9.21'
+//}
+apply plugin: 'kotlinx-atomicfu'
+
+repositories {
+    mavenCentral()
+    maven{ url = "https://maven.pkg.jetbrains.space/kotlin/p/kotlin/dev" }
+    mavenLocal()
+}
+
+kotlin {
+    jvm()
+
+    js()
+
+    wasmJs {}
+    wasmWasi {}
+
+    macosArm64()
+    macosX64()
+    linuxArm64()
+    linuxX64()
+    mingwX64()
+
+    sourceSets {
+        commonMain {
+            dependencies {
+                implementation(kotlin("stdlib"))
+                implementation(kotlin("test-junit"))
+            }
+        }
+        commonTest {}
+    }
+}

integration-testing/examples/plugin-order-bug/gradle.properties

@@ -0,0 +1,5 @@
+##
+## Copyright 2016-2023 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+##
+kotlin_version=1.9.21
+atomicfu_version=0.23.1-SNAPSHOT

integration-testing/examples/plugin-order-bug/settings.gradle.kts

@@ -0,0 +1,19 @@
+pluginManagement {
+    repositories {
+        mavenLocal()
+        mavenCentral()
+        maven("https://maven.pkg.jetbrains.space/kotlin/p/kotlin/dev")
+        gradlePluginPortal()
+    }
+}
+
+dependencyResolutionManagement {
+    versionCatalogs {
+        create("libs") {
+            version("atomicfuVersion", providers.gradleProperty("atomicfu_version").orNull)
+            version("kotlinVersion", providers.gradleProperty("kotlin_version").orNull)
+        }
+    }
+}
+
+rootProject.name = "plugin-order-bug"

integration-testing/examples/plugin-order-bug/src/commonMain/kotlin/AtomicSampleClass.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2016-2023 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package examples.mpp_sample
+
+import kotlinx.atomicfu.*
+import kotlinx.atomicfu.locks.*
+import kotlin.test.*
+
+public class AtomicSampleClass {
+    private val _x = atomic(0)
+    val x get() = _x.value
+
+    public fun doWork(finalValue: Int) {
+        assertEquals(0, x)
+        assertEquals(0, _x.getAndSet(3))
+        assertEquals(3, x)
+        assertTrue(_x.compareAndSet(3, finalValue))
+    }
+
+    private val lock = reentrantLock()
+
+    public fun synchronizedFoo(value: Int): Int {
+        return lock.withLock { value }
+    }
+}

integration-testing/examples/plugin-order-bug/src/commonTest/kotlin/AtomicSampleTest.kt

@@ -0,0 +1,17 @@
+/*
+ * Copyright 2016-2023 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+import kotlin.test.*
+import examples.mpp_sample.*
+
+class AtomicSampleTest {
+
+    @Test
+    fun testInt() {
+        val a = AtomicSampleClass()
+        a.doWork(1234)
+        assertEquals(1234, a.x)
+        assertEquals(42, a.synchronizedFoo(42))
+    }
+}

integration-testing/src/functionalTest/kotlin/kotlinx.atomicfu.gradle.plugin.test/cases/PluginOrderBugTest.kt

@@ -0,0 +1,21 @@
+package kotlinx.atomicfu.gradle.plugin.test.cases
+
+import kotlinx.atomicfu.gradle.plugin.test.framework.runner.*
+import kotlinx.atomicfu.gradle.plugin.test.framework.runner.GradleBuild
+import kotlinx.atomicfu.gradle.plugin.test.framework.runner.cleanAndBuild
+import kotlinx.atomicfu.gradle.plugin.test.framework.runner.createGradleBuildFromSources
+import kotlin.test.*
+
+/**
+ * This test reproduces and tracks the issue #384.
+ */
+class PluginOrderBugTest {
+    private val pluginOrderBugProject: GradleBuild = createGradleBuildFromSources("plugin-order-bug")
+
+    @Test
+    fun testUserProjectBuild() {
+        val buildResult = pluginOrderBugProject.cleanAndBuild()
+        assertFalse(buildResult.isSuccessful)
+        assertTrue(buildResult.output.contains("unresolved reference: kotlinx"), buildResult.output)
+    }
+}

integration-testing/src/functionalTest/kotlin/kotlinx.atomicfu.gradle.plugin.test/framework/runner/BuildRunner.kt

@@ -25,10 +25,7 @@ internal class GradleBuild(val projectName: String, val targetDir: File) {
 
     private var runCount = 0
 
-    fun runGradle(commands: List<String>): BuildResult =
-        buildGradleByShell(runCount++, commands, properties).also {
-            require(it.isSuccessful) { "Running $commands on project $projectName FAILED with error:\n" + it.output }
-        }
+    fun runGradle(commands: List<String>): BuildResult = buildGradleByShell(runCount++, commands, properties)
 }
 
 internal class BuildResult(exitCode: Int, private val logFile: File) {

integration-testing/src/functionalTest/kotlin/kotlinx.atomicfu.gradle.plugin.test/framework/runner/Commands.kt

@@ -6,7 +6,12 @@ package kotlinx.atomicfu.gradle.plugin.test.framework.runner
 
 internal fun GradleBuild.cleanAndBuild(): BuildResult = runGradle(listOf("clean", "build"))
 
-internal fun GradleBuild.dependencies(): BuildResult = runGradle(listOf("dependencies"))
+internal fun GradleBuild.dependencies(): BuildResult = 
+    runGradle(listOf("dependencies")).also { 
+        require(it.isSuccessful) { "${this.projectName}:dependencies task FAILED: ${it.output} " }
+    }
 
 internal fun GradleBuild.publishToLocalRepository(): BuildResult =
-    runGradle(listOf("clean", "publish"))
+    runGradle(listOf("clean", "publish")).also {
+        require(it.isSuccessful) { "${this.projectName}:publish task FAILED: ${it.output} " }
+    }