Fix no duplicate strategy was set for compilation with 'withJava()'.

In such case Kotlin jvm compilation has additionally java resource dir
that points to the same location. So ProcessResources task copies same
file twice. Fixed by setting ignore duplicates strategy.

^KT-46978 Fixed

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/kotlin/org/jetbrains/kotlin/gradle/MultiplatformGradleIT.kt

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.gradle
 
 import com.intellij.testFramework.TestDataPath
+import org.gradle.api.logging.LogLevel
 import org.gradle.api.logging.configuration.WarningMode
 import org.jetbrains.kotlin.gradle.internals.KOTLIN_12X_MPP_DEPRECATION_WARNING
 import org.jetbrains.kotlin.gradle.plugin.EXPECTED_BY_CONFIG_NAME
@@ -310,4 +311,40 @@ class MultiplatformGradleIT : BaseGradleIT() {
             assertTasksExecuted(customSourceSetCompileTasks)
         }
     }
+
+    @Test
+    fun testWithJavaDuplicatedResourcesFail() = with(
+        Project(
+            projectName = "mpp-single-jvm-target",
+            gradleVersionRequirement = GradleVersionRequired.AtLeast("7.0"),
+            minLogLevel = LogLevel.WARN
+        )
+    ) {
+        setupWorkingDir()
+
+        gradleBuildScript().modify { buildFileContent ->
+            buildFileContent
+                .lines()
+                .joinToString(separator = "\n") {
+                    if (it.contains("jvm()")) {
+                        "jvm { withJava() }"
+                    } else {
+                        it
+                    }
+                }
+        }
+
+        val resDir = projectDir.resolve("src/jvmMain/resources").also { it.mkdirs() }
+        resDir.resolve("test.properties").writeText(
+            """
+            one=true
+            two=false
+            """.trimIndent()
+        )
+
+        build("assemble") {
+            assertSuccessful()
+            assertNotContains("no duplicate handling strategy has been set")
+        }
+    }
 }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/jvm/KotlinJvmTarget.kt

@@ -9,12 +9,14 @@ import org.gradle.api.InvalidUserCodeException
 import org.gradle.api.NamedDomainObjectContainer
 import org.gradle.api.Project
 import org.gradle.api.file.ConfigurableFileCollection
+import org.gradle.api.file.DuplicatesStrategy
 import org.gradle.api.plugins.JavaPlugin
 import org.gradle.api.plugins.JavaPluginConvention
 import org.gradle.api.tasks.SourceSet
 import org.gradle.api.tasks.compile.AbstractCompile
 import org.gradle.api.tasks.testing.Test
 import org.gradle.jvm.tasks.Jar
+import org.gradle.language.jvm.tasks.ProcessResources
 import org.gradle.util.GradleVersion
 import org.jetbrains.kotlin.gradle.dsl.multiplatformExtension
 import org.jetbrains.kotlin.gradle.plugin.*
@@ -101,11 +103,21 @@ open class KotlinJvmTarget @Inject constructor(
         // sources are placed (i.e. src/jvmMain/java, src/jvmTest/java):
         javaSourceSet.resources.setSrcDirs(compilation.defaultSourceSet.resources.sourceDirectories)
         compilation.defaultSourceSet.resources.srcDirs(javaSourceSet.resources.sourceDirectories)
+        project.tasks.named(
+            compilation.processResourcesTaskName,
+            ProcessResources::class.java
+        ).configure {
+            // Now 'compilation' has additional resources dir from java compilation which points to the initial
+            // resources location. Because of this, ProcessResources task will copy same files twice,
+            // so we are excluding duplicates.
+            it.duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+        }
 
         // Resources processing is done with the Kotlin resource processing task:
-        val processJavaResourcesTask = project.tasks.getByName(javaSourceSet.processResourcesTaskName)
-        processJavaResourcesTask.dependsOn(project.tasks.getByName(compilation.processResourcesTaskName))
-        processJavaResourcesTask.enabled = false
+        project.tasks.named(javaSourceSet.processResourcesTaskName).configure {
+            it.dependsOn(project.tasks.named(compilation.processResourcesTaskName))
+            it.enabled = false
+        }
     }
 
     private fun disableJavaPluginTasks(javaPluginConvention: JavaPluginConvention) {