Light classes: fix multifile facades for mpp modules with jvm part

When creating multifile facades respect that facade files can be both
    in common and jvm parts

 #KT-23942 Fixed

idea/idea-analysis/src/org/jetbrains/kotlin/idea/caches/project/IdeaModuleInfos.kt

@@ -400,9 +400,9 @@ interface SourceForBinaryModuleInfo : IdeaModuleInfo {
         get() = ModuleOrigin.OTHER
 }
 
-class PlatformModuleInfo(
+data class PlatformModuleInfo(
     internal val platformModule: ModuleSourceInfo,
-    private val commonModules: List<ModuleSourceInfo>
+    private val commonModules: List<ModuleSourceInfo> // NOTE: usually contains a single element for current implementation
 ) : IdeaModuleInfo, CombinedModuleInfo, TrackableModuleInfo {
     override val capabilities: Map<ModuleDescriptor.Capability<*>, Any?>
         get() = platformModule.capabilities

idea/idea-analysis/src/org/jetbrains/kotlin/idea/caches/project/multiplatformUtil.kt

@@ -11,12 +11,14 @@ import com.intellij.openapi.externalSystem.service.project.IdeModelsProviderImpl
 import com.intellij.openapi.module.Module
 import com.intellij.openapi.module.ModuleManager
 import com.intellij.openapi.roots.ProjectRootModificationTracker
+import com.intellij.psi.PsiElement
 import com.intellij.psi.util.CachedValueProvider
 import org.jetbrains.kotlin.analyzer.ModuleInfo
 import org.jetbrains.kotlin.caches.resolve.KotlinCacheService
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.idea.facet.KotlinFacetType
 import org.jetbrains.kotlin.idea.facet.KotlinFacetType.Companion.ID
+import org.jetbrains.kotlin.resolve.TargetPlatform
 
 val Module.implementingModules: List<Module>
     get() = cached(CachedValueProvider {
@@ -72,3 +74,20 @@ val ModuleDescriptor.implementedDescriptors: List<ModuleDescriptor>
 
 private fun ModuleSourceInfo.toDescriptor() = KotlinCacheService.getInstance(module.project)
     .getResolutionFacadeByModuleInfo(this, platform)?.moduleDescriptor
+
+fun PsiElement.getPlatformModuleInfo(desiredPlatform: TargetPlatform): PlatformModuleInfo? {
+    assert(desiredPlatform != TargetPlatform.Common) { "Platform module cannot have Common platform" }
+    val moduleInfo = getModuleInfo() as? ModuleSourceInfo ?: return null
+    return when (moduleInfo.platform) {
+        TargetPlatform.Common -> {
+            val correspondingImplementingModule = moduleInfo.module.implementingModules.map { it.toInfo(moduleInfo.isTests()) }
+                .firstOrNull { it?.platform == desiredPlatform } ?: return null
+            PlatformModuleInfo(correspondingImplementingModule, correspondingImplementingModule.expectedBy)
+        }
+        desiredPlatform -> {
+            val expectedBy = moduleInfo.expectedBy.takeIf { it.isNotEmpty() } ?: return null
+            PlatformModuleInfo(moduleInfo, expectedBy)
+        }
+        else -> null
+    }
+}

idea/idea-analysis/src/org/jetbrains/kotlin/idea/caches/resolve/IDEKotlinAsJavaSupport.kt

@@ -19,16 +19,17 @@ import org.jetbrains.kotlin.fileClasses.javaFileFacadeFqName
 import org.jetbrains.kotlin.idea.caches.lightClasses.ClsJavaStubByVirtualFileCache
 import org.jetbrains.kotlin.idea.caches.lightClasses.KtLightClassForDecompiledDeclaration
 import org.jetbrains.kotlin.idea.caches.lightClasses.platformMutabilityWrapper
+import org.jetbrains.kotlin.idea.caches.project.*
 import org.jetbrains.kotlin.idea.caches.project.IdeaModuleInfo
-import org.jetbrains.kotlin.idea.caches.project.ModuleSourceInfo
-import org.jetbrains.kotlin.idea.caches.project.getModuleInfo
 import org.jetbrains.kotlin.idea.decompiler.classFile.KtClsFile
 import org.jetbrains.kotlin.idea.decompiler.navigation.SourceNavigationHelper
+import org.jetbrains.kotlin.idea.project.platform
 import org.jetbrains.kotlin.idea.stubindex.*
 import org.jetbrains.kotlin.idea.util.ProjectRootsUtil
 import org.jetbrains.kotlin.idea.util.application.runReadAction
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.resolve.jvm.platform.JvmPlatform
 import org.jetbrains.kotlin.resolve.scopes.MemberScope
 import org.jetbrains.kotlin.utils.sure
 import java.util.*
@@ -47,10 +48,10 @@ class IDEKotlinAsJavaSupport(private val project: Project): KotlinAsJavaSupport(
     override fun getFacadeClassesInPackage(packageFqName: FqName, scope: GlobalSearchScope): Collection<PsiClass> {
         val facadeFilesInPackage = runReadAction {
             KotlinFileFacadeClassByPackageIndex.getInstance()
-                .get(packageFqName.asString(), project, scope)
+                .get(packageFqName.asString(), project, scope).platformSourcesFirst()
         }
         val groupedByFqNameAndModuleInfo = facadeFilesInPackage.groupBy {
-            Pair(it.javaFileFacadeFqName, it.getModuleInfo())
+            Pair(it.javaFileFacadeFqName, it.getModuleInfoPreferringJvmPlatform())
         }
 
         return groupedByFqNameAndModuleInfo.flatMap {
@@ -141,11 +142,9 @@ class IDEKotlinAsJavaSupport(private val project: Project): KotlinAsJavaSupport(
         KtLightClassForScript.create(script)
 
     private fun withFakeLightClasses(
-        lightClassForFacade: KtLightClassForFacade?,
+        lightClassForFacade: KtLightClassForFacade,
         facadeFiles: List<KtFile>
     ): List<PsiClass> {
-        if (lightClassForFacade == null) return emptyList()
-
         val lightClasses = ArrayList<PsiClass>()
         lightClasses.add(lightClassForFacade)
         if (facadeFiles.size > 1) {
@@ -157,7 +156,7 @@ class IDEKotlinAsJavaSupport(private val project: Project): KotlinAsJavaSupport(
     }
 
     override fun getFacadeClasses(facadeFqName: FqName, scope: GlobalSearchScope): Collection<PsiClass> {
-        val filesByModule = findFilesForFacade(facadeFqName, scope).groupBy(KtFile::getModuleInfo)
+        val filesByModule = findFilesForFacade(facadeFqName, scope).groupBy(PsiElement::getModuleInfoPreferringJvmPlatform)
 
         return filesByModule.flatMap {
             createLightClassForFileFacade(facadeFqName, it.value, it.key)
@@ -209,23 +208,40 @@ class IDEKotlinAsJavaSupport(private val project: Project): KotlinAsJavaSupport(
         moduleInfo: IdeaModuleInfo
     ): List<PsiClass> {
         val (clsFiles, sourceFiles) = facadeFiles.partition { it is KtClsFile }
-        val lightClassesForClsFacades = clsFiles.mapNotNull { createLightClassForDecompiledKotlinFile(it as KtClsFile) }
-        if (moduleInfo is ModuleSourceInfo && sourceFiles.isNotEmpty()) {
-            val lightClassForFacade = KtLightClassForFacade.createForFacade(
-                psiManager, facadeFqName, moduleInfo.contentScope(), sourceFiles
-            )
-            return withFakeLightClasses(lightClassForFacade, sourceFiles) + lightClassesForClsFacades
-        } else {
-            return lightClassesForClsFacades
-        }
+        val facadesFromCls = clsFiles.mapNotNull { createLightClassForDecompiledKotlinFile(it as KtClsFile) }
+        val facadesFromSources = createFacadesForSourceFiles(moduleInfo, sourceFiles, facadeFqName)
+        return facadesFromSources + facadesFromCls
+    }
+
+    private fun createFacadesForSourceFiles(
+        moduleInfo: IdeaModuleInfo,
+        sourceFiles: List<KtFile>,
+        facadeFqName: FqName
+    ): List<PsiClass> {
+        if (sourceFiles.isEmpty()) return listOf()
+        if (moduleInfo !is ModuleSourceInfo && moduleInfo !is PlatformModuleInfo) return listOf()
+
+        val lightClassForFacade = KtLightClassForFacade.createForFacade(
+            psiManager, facadeFqName, moduleInfo.contentScope(), sourceFiles
+        )
+        return withFakeLightClasses(lightClassForFacade, sourceFiles)
     }
 
     override fun findFilesForFacade(facadeFqName: FqName, scope: GlobalSearchScope): Collection<KtFile> {
         return runReadAction {
-            KotlinFileFacadeFqNameIndex.INSTANCE.get(facadeFqName.asString(), project, scope)
+            KotlinFileFacadeFqNameIndex.INSTANCE.get(facadeFqName.asString(), project, scope).platformSourcesFirst()
         }
     }
 
+
+    // NOTE: this is a hacky solution to the following problem:
+    // when building this light class resolver will be built by the first file in the list
+    // (we could assume that files are in the same module before)
+    // thus we need to ensure that resolver will be built by the file from platform part of the module
+    // (resolver built by a file from the common part will have no knowledge of the platform part)
+    // the actual of order of files that resolver receives is controlled by *findFilesForFacade* method
+    private fun Collection<KtFile>.platformSourcesFirst() = sortedByDescending { it.platform == JvmPlatform }
+
     private fun getLightClassForDecompiledClassOrObject(decompiledClassOrObject: KtClassOrObject): KtLightClassForDecompiledDeclaration? {
         if (decompiledClassOrObject is KtEnumEntry) {
             return null
@@ -307,4 +323,8 @@ class IDEKotlinAsJavaSupport(private val project: Project): KotlinAsJavaSupport(
         javaFileStub.psi = fakeFile
         return fakeFile.classes.single() as ClsClassImpl
     }
+}
+
+internal fun PsiElement.getModuleInfoPreferringJvmPlatform(): IdeaModuleInfo {
+    return getPlatformModuleInfo(JvmPlatform) ?: getModuleInfo()
 }

idea/idea-analysis/src/org/jetbrains/kotlin/idea/caches/resolve/KtFileClassProviderImpl.kt

@@ -29,7 +29,7 @@ class KtFileClassProviderImpl(val kotlinAsJavaSupport: KotlinAsJavaSupport) :
         val result = arrayListOf<PsiClass>()
         file.declarations.filterIsInstance<KtClassOrObject>().map { it.toLightClass() }.filterNotNullTo(result)
 
-        val moduleInfo = file.getModuleInfo()
+        val moduleInfo = file.getModuleInfoPreferringJvmPlatform()
         val jvmClassInfo = JvmFileClassUtil.getFileClassInfoNoResolve(file)
         val fileClassFqName = file.javaFileFacadeFqName