Internal visibility between common source sets in Gradle (KT-37264)

In KotlinCompileCommon, pass the friendPaths and refinesPaths arguments

In KotlinNativeCompilation, add both friend and refined dependencies as
friends for now.

In getVisibleSourceSetsFromAssociateCompilations, exclude the metadata
compilations to avoid incorrect results (those compilations don't have
proper kotlin

Issue #KT-37264 Fixed

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/common-klib-lib-and-app/src/commonMain/kotlin/LibCommonMain.kt

@@ -11,6 +11,8 @@ fun libCommonMainTopLevelFun(): Int {
     return 2
 }
 
+fun libCommonMainInternalFun() = Unit
+
 fun main() {
     
 }

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/common-klib-lib-and-app/src/jvmAndJsMain/kotlin/LibJvmAndJsMain.kt

@@ -4,6 +4,7 @@ actual class LibCommonMainExpect : LibCommonMainIface {
     actual fun libCommonMainExpectFun(): Unit {
         println("actualized in jvmAndJsMain")
         libCommonMainTopLevelFun()
+        libCommonMainInternalFun()
     }
 
     fun additionalFunInJvmAndJsActual() {

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/common-klib-lib-and-app/src/jvmMain/kotlin/LibJvmMain.kt

@@ -2,4 +2,5 @@ package com.h0tk3y.hmpp.klib.demo
 
 fun main() {
     libCommonMainTopLevelFun()
+    libCommonMainInternalFun()
 }

libraries/tools/kotlin-gradle-plugin-integration-tests/src/test/resources/testProject/common-klib-lib-and-app/src/linuxMain/kotlin/LibLinuxMain.kt

@@ -12,6 +12,7 @@ actual class LibCommonMainExpect : LibCommonMainIface {
         println("actualized in iosMain")
         libCommonMainTopLevelFun()
         println(CArrayPointer::class)
+        libCommonMainInternalFun()
     }
 
     fun additionalFunInLinuxActual() {

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/mpp/KotlinCommonCompilation.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.gradle.plugin.mpp
 
+import org.gradle.api.file.FileCollection
 import org.jetbrains.kotlin.gradle.dsl.KotlinCommonOptions
 import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformCommonOptions
 import org.jetbrains.kotlin.gradle.dsl.kotlinExtension
@@ -12,6 +13,7 @@ import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation
 import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSet
 import org.jetbrains.kotlin.gradle.plugin.KotlinTarget
 import org.jetbrains.kotlin.gradle.plugin.PropertiesProvider
+import org.jetbrains.kotlin.gradle.plugin.sources.getVisibleSourceSetsFromAssociateCompilations
 import org.jetbrains.kotlin.gradle.tasks.KotlinCompileCommon
 
 interface KotlinMetadataCompilation<T : KotlinCommonOptions> : KotlinCompilation<T>
@@ -27,4 +29,11 @@ class KotlinCommonCompilation(
         get() = PropertiesProvider(target.project).enableGranularSourceSetsMetadata == true && !forceCompilationToKotlinMetadata
 
     internal var forceCompilationToKotlinMetadata: Boolean = false
+
+    override val friendArtifacts: FileCollection
+        get() = super.friendArtifacts.plus(run {
+            val project = target.project
+            val friendSourceSets = getVisibleSourceSetsFromAssociateCompilations(target.project, defaultSourceSet)
+            project.files(friendSourceSets.mapNotNull { target.compilations.findByName(it.name)?.output?.classesDirs })
+        })
 }

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/native/KotlinNativeCompilation.kt

@@ -11,6 +11,7 @@ import org.gradle.api.Action
 import org.gradle.api.NamedDomainObjectContainer
 import org.gradle.api.Project
 import org.gradle.api.file.ConfigurableFileCollection
+import org.gradle.api.file.FileCollection
 import org.gradle.api.file.SourceDirectorySet
 import org.gradle.util.ConfigureUtil
 import org.jetbrains.kotlin.gradle.dsl.KotlinCommonOptions
@@ -18,6 +19,8 @@ import org.jetbrains.kotlin.gradle.plugin.KotlinCompilation
 import org.jetbrains.kotlin.gradle.plugin.KotlinCompilationWithResources
 import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSet
 import org.jetbrains.kotlin.gradle.plugin.KotlinTarget
+import org.jetbrains.kotlin.gradle.plugin.sources.getSourceSetHierarchy
+import org.jetbrains.kotlin.gradle.plugin.sources.getVisibleSourceSetsFromAssociateCompilations
 import org.jetbrains.kotlin.gradle.tasks.KotlinNativeCompile
 import org.jetbrains.kotlin.gradle.utils.SingleWarningPerBuild
 import org.jetbrains.kotlin.gradle.utils.lowerCamelCaseName
@@ -96,4 +99,17 @@ class KotlinNativeCompilation(
 
 class KotlinSharedNativeCompilation(override val target: KotlinMetadataTarget, name: String) :
     AbstractKotlinNativeCompilation(target, HostManager.host, name),
-    KotlinMetadataCompilation<KotlinCommonOptions>
+    KotlinMetadataCompilation<KotlinCommonOptions> {
+
+    override val friendArtifacts: FileCollection
+        get() = super.friendArtifacts.plus(run {
+            val project = target.project
+            val friendSourceSets = getVisibleSourceSetsFromAssociateCompilations(project, defaultSourceSet).toMutableSet().apply {
+                // TODO: implement proper dependsOn/refines compiler args for Kotlin/Native and pass the dependsOn klibs separately;
+                //       But for now, those dependencies don't have any special semantics, so passing all them as friends works, too
+                addAll(defaultSourceSet.getSourceSetHierarchy())
+                remove(defaultSourceSet)
+            }
+            project.files(friendSourceSets.mapNotNull { target.compilations.findByName(it.name)?.output?.classesDirs })
+        })
+}

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/tasks/KotlinCompileCommon.kt

@@ -18,6 +18,9 @@ package org.jetbrains.kotlin.gradle.tasks
 
 import org.gradle.api.Project
 import org.gradle.api.tasks.CacheableTask
+import org.gradle.api.tasks.InputFiles
+import org.gradle.api.tasks.PathSensitive
+import org.gradle.api.tasks.PathSensitivity
 import org.jetbrains.kotlin.cli.common.arguments.K2MetadataCompilerArguments
 import org.jetbrains.kotlin.compilerRunner.GradleCompilerEnvironment
 import org.jetbrains.kotlin.compilerRunner.OutputItemsCollectorImpl
@@ -27,8 +30,10 @@ import org.jetbrains.kotlin.gradle.dsl.KotlinMultiplatformCommonOptionsImpl
 import org.jetbrains.kotlin.gradle.dsl.fillDefaultValues
 import org.jetbrains.kotlin.gradle.internal.tasks.allOutputFiles
 import org.jetbrains.kotlin.gradle.logging.GradlePrintingMessageCollector
+import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSet
 import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinCommonCompilation
-import org.jetbrains.kotlin.gradle.plugin.mpp.KotlinMetadataCompilation
+import org.jetbrains.kotlin.gradle.utils.getValue
+import org.jetbrains.kotlin.gradle.plugin.sources.getSourceSetHierarchy
 import org.jetbrains.kotlin.incremental.ChangedFiles
 import java.io.File
 
@@ -65,11 +70,30 @@ open class KotlinCompileCommon : AbstractKotlinCompile<K2MetadataCompilerArgumen
         with(args) {
             classpath = classpathList.joinToString(File.pathSeparator)
             destination = destinationDir.canonicalPath
+
+            friendPaths = this@KotlinCompileCommon.friendPaths
+            refinesPaths = refinesMetadataPaths.map { it.absolutePath }.toTypedArray()
         }
 
         kotlinOptionsImpl.updateArguments(args)
     }
 
+    private fun outputPathsFromMetadataCompilationsOf(sourceSets: Iterable<KotlinSourceSet>): List<File> {
+        val target = taskData.compilation.target
+        return sourceSets
+            .mapNotNull { sourceSet -> target.compilations.findByName(sourceSet.name)?.output?.classesDirs }
+            .flatten()
+    }
+
+    private val defaultKotlinSourceSet: KotlinSourceSet
+        get() = taskData.compilation.defaultSourceSet
+
+    @get:PathSensitive(PathSensitivity.RELATIVE)
+    @get:InputFiles
+    internal val refinesMetadataPaths by project.provider {
+        outputPathsFromMetadataCompilationsOf(defaultKotlinSourceSet.getSourceSetHierarchy().minus(defaultKotlinSourceSet))
+    }
+
     override fun callCompilerAsync(args: K2MetadataCompilerArguments, sourceRoots: SourceRoots, changedFiles: ChangedFiles) {
         val messageCollector = GradlePrintingMessageCollector(logger)
         val outputItemCollector = OutputItemsCollectorImpl()