Extract new method from the publicly used interface for compatibility

Note that we can't just use ``@JvmDefault` annotation as the main change
 is in the `core` module which targets Java 6

 #KT-42259 Fixed

compiler/frontend.java/src/org/jetbrains/kotlin/load/kotlin/incremental/IncrementalPackageFragmentProvider.kt

@@ -18,7 +18,7 @@ package org.jetbrains.kotlin.load.kotlin.incremental
 
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
-import org.jetbrains.kotlin.descriptors.PackageFragmentProvider
+import org.jetbrains.kotlin.descriptors.PackageFragmentProviderOptimized
 import org.jetbrains.kotlin.descriptors.impl.PackageFragmentDescriptorImpl
 import org.jetbrains.kotlin.load.kotlin.JvmPackagePartSource
 import org.jetbrains.kotlin.load.kotlin.KotlinClassFinder
@@ -49,7 +49,7 @@ class IncrementalPackageFragmentProvider(
     val incrementalCache: IncrementalCache,
     val target: TargetId,
     private val kotlinClassFinder: KotlinClassFinder
-) : PackageFragmentProvider {
+) : PackageFragmentProviderOptimized {
     private val fqNameToPackageFragment =
         PackagePartClassUtils.getFilesWithCallables(sourceFiles)
             .mapTo(hashSetOf()) { it.packageFqName }

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/multiplatform/OptionalAnnotationPackageFragmentProvider.kt

@@ -33,7 +33,7 @@ class OptionalAnnotationPackageFragmentProvider(
     notFoundClasses: NotFoundClasses,
     languageVersionSettings: LanguageVersionSettings,
     packagePartProvider: PackagePartProvider,
-) : PackageFragmentProvider {
+) : PackageFragmentProviderOptimized {
     val packages: Map<FqName, PackageFragmentDescriptor> by storageManager.createLazyValue p@{
         // We call getAllOptionalAnnotationClasses under lazy value only because IncrementalPackagePartProvider requires
         // deserializationConfiguration to be injected.

compiler/frontend/src/org/jetbrains/kotlin/analyzer/AbstractResolverForProject.kt

@@ -8,9 +8,7 @@ package org.jetbrains.kotlin.analyzer
 import com.intellij.openapi.util.ModificationTracker
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.context.ProjectContext
-import org.jetbrains.kotlin.descriptors.ModuleDescriptor
+import org.jetbrains.kotlin.descriptors.*
-import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
-import org.jetbrains.kotlin.descriptors.PackageFragmentProvider
 import org.jetbrains.kotlin.descriptors.impl.ModuleDescriptorImpl
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
@@ -238,7 +236,7 @@ private class DelegatingPackageFragmentProvider<M : ModuleInfo>(
     private val module: ModuleDescriptor,
     moduleContent: ModuleContent<M>,
     private val packageOracle: PackageOracle
-) : PackageFragmentProvider {
+) : PackageFragmentProviderOptimized {
     private val syntheticFilePackages = moduleContent.syntheticFiles.map { it.packageFqName }.toSet()
 
     override fun getPackageFragments(fqName: FqName): List<PackageFragmentDescriptor> {
@@ -250,7 +248,7 @@ private class DelegatingPackageFragmentProvider<M : ModuleInfo>(
     override fun collectPackageFragments(fqName: FqName, packageFragments: MutableCollection<PackageFragmentDescriptor>) {
         if (certainlyDoesNotExist(fqName)) return
 
-        resolverForProject.resolverForModuleDescriptor(module).packageFragmentProvider.collectPackageFragments(fqName, packageFragments)
+        resolverForProject.resolverForModuleDescriptor(module).packageFragmentProvider.collectPackageFragmentsOptimizedIfPossible(fqName, packageFragments)
     }
 
     override fun getSubPackagesOf(fqName: FqName, nameFilter: (Name) -> Boolean): Collection<FqName> {

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/ResolveSession.java

@@ -179,7 +179,7 @@ public class ResolveSession implements KotlinCodeAnalyzer, LazyClassContext {
 
         this.declarationProviderFactory = declarationProviderFactory;
 
-        this.packageFragmentProvider = new PackageFragmentProvider() {
+        this.packageFragmentProvider = new PackageFragmentProviderOptimized() {
             @Override
             public void collectPackageFragments(
                     @NotNull FqName fqName, @NotNull Collection<PackageFragmentDescriptor> packageFragments

core/descriptors.jvm/src/org/jetbrains/kotlin/load/java/lazy/LazyJavaPackageFragmentProvider.kt

@@ -17,7 +17,7 @@
 package org.jetbrains.kotlin.load.java.lazy
 
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
-import org.jetbrains.kotlin.descriptors.PackageFragmentProvider
+import org.jetbrains.kotlin.descriptors.PackageFragmentProviderOptimized
 import org.jetbrains.kotlin.load.java.lazy.descriptors.LazyJavaPackageFragment
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
@@ -26,7 +26,7 @@ import org.jetbrains.kotlin.utils.addIfNotNull
 
 class LazyJavaPackageFragmentProvider(
     components: JavaResolverComponents
-) : PackageFragmentProvider {
+) : PackageFragmentProviderOptimized {
 
     private val c = LazyJavaResolverContext(components, TypeParameterResolver.EMPTY, lazyOf(null))
 

core/descriptors/src/org/jetbrains/kotlin/descriptors/PackageFragmentProvider.kt

@@ -20,27 +20,35 @@ import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 
 interface PackageFragmentProvider {
-    fun collectPackageFragments(fqName: FqName, packageFragments: MutableCollection<PackageFragmentDescriptor>) {
-        // default implementation is provided only for BWC
-        packageFragments.addAll(getPackageFragments(fqName))
-    }
-
     @Deprecated("for usages use #packageFragments(FqName) at final point, for impl use #collectPackageFragments(FqName, MutableCollection<PackageFragmentDescriptor>)")
     fun getPackageFragments(fqName: FqName): List<PackageFragmentDescriptor>
 
     fun getSubPackagesOf(fqName: FqName, nameFilter: (Name) -> Boolean): Collection<FqName>
 
     object Empty : PackageFragmentProvider {
-        override fun collectPackageFragments(fqName: FqName, packageFragments: MutableCollection<PackageFragmentDescriptor>) {}
-
         override fun getPackageFragments(fqName: FqName) = emptyList<PackageFragmentDescriptor>()
 
         override fun getSubPackagesOf(fqName: FqName, nameFilter: (Name) -> Boolean) = emptySet<FqName>()
     }
 }
 
+interface PackageFragmentProviderOptimized : PackageFragmentProvider {
+    fun collectPackageFragments(fqName: FqName, packageFragments: MutableCollection<PackageFragmentDescriptor>)
+}
+
 fun PackageFragmentProvider.packageFragments(fqName: FqName): List<PackageFragmentDescriptor> {
     val packageFragments = mutableListOf<PackageFragmentDescriptor>()
-    collectPackageFragments(fqName, packageFragments)
+    collectPackageFragmentsOptimizedIfPossible(fqName, packageFragments)
     return packageFragments
 }
+
+fun PackageFragmentProvider.collectPackageFragmentsOptimizedIfPossible(
+    fqName: FqName,
+    packageFragments: MutableCollection<PackageFragmentDescriptor>
+) {
+    when (this) {
+        is PackageFragmentProviderOptimized -> collectPackageFragments(fqName, packageFragments)
+        else -> packageFragments.addAll(getPackageFragments(fqName))
+    }
+}
+

core/descriptors/src/org/jetbrains/kotlin/descriptors/PackageFragmentProviderImpl.kt

@@ -21,7 +21,7 @@ import org.jetbrains.kotlin.name.Name
 
 class PackageFragmentProviderImpl(
     private val packageFragments: Collection<PackageFragmentDescriptor>
-) : PackageFragmentProvider {
+) : PackageFragmentProviderOptimized {
     override fun collectPackageFragments(fqName: FqName, packageFragments: MutableCollection<PackageFragmentDescriptor>) {
         this.packageFragments.filterTo(packageFragments) { it.fqName == fqName }
     }

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/CompositePackageFragmentProvider.kt

@@ -18,13 +18,15 @@ package org.jetbrains.kotlin.descriptors.impl
 
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentProvider
+import org.jetbrains.kotlin.descriptors.PackageFragmentProviderOptimized
+import org.jetbrains.kotlin.descriptors.collectPackageFragmentsOptimizedIfPossible
 import org.jetbrains.kotlin.name.FqName
 import java.util.*
 import org.jetbrains.kotlin.name.Name
 
 class CompositePackageFragmentProvider(// can be modified from outside
     private val providers: List<PackageFragmentProvider>
-) : PackageFragmentProvider {
+) : PackageFragmentProviderOptimized {
 
     init {
         assert(providers.size == providers.toSet().size) {
@@ -35,14 +37,14 @@ class CompositePackageFragmentProvider(// can be modified from outside
     override fun getPackageFragments(fqName: FqName): List<PackageFragmentDescriptor> {
         val result = ArrayList<PackageFragmentDescriptor>()
         for (provider in providers) {
-            provider.collectPackageFragments(fqName, result)
+            provider.collectPackageFragmentsOptimizedIfPossible(fqName, result)
         }
         return result.toList()
     }
 
     override fun collectPackageFragments(fqName: FqName, packageFragments: MutableCollection<PackageFragmentDescriptor>) {
         for (provider in providers) {
-            provider.collectPackageFragments(fqName, packageFragments)
+            provider.collectPackageFragmentsOptimizedIfPossible(fqName, packageFragments)
         }
     }
 

core/deserialization/src/org/jetbrains/kotlin/serialization/deserialization/AbstractDeserializedPackageFragmentProvider.kt

@@ -18,7 +18,7 @@ package org.jetbrains.kotlin.serialization.deserialization
 
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
-import org.jetbrains.kotlin.descriptors.PackageFragmentProvider
+import org.jetbrains.kotlin.descriptors.PackageFragmentProviderOptimized
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.storage.StorageManager
@@ -28,7 +28,7 @@ abstract class AbstractDeserializedPackageFragmentProvider(
     protected val storageManager: StorageManager,
     protected val finder: KotlinMetadataFinder,
     protected val moduleDescriptor: ModuleDescriptor
-) : PackageFragmentProvider {
+) : PackageFragmentProviderOptimized {
     protected lateinit var components: DeserializationComponents
 
     private val fragments = storageManager.createMemoizedFunctionWithNullableValues<FqName, PackageFragmentDescriptor> { fqName ->

idea/idea-analysis/src/org/jetbrains/kotlin/idea/decompiler/textBuilder/DeserializerForDecompilerBase.kt

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.idea.decompiler.textBuilder
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentProvider
+import org.jetbrains.kotlin.descriptors.PackageFragmentProviderOptimized
 import org.jetbrains.kotlin.descriptors.impl.ModuleDescriptorImpl
 import org.jetbrains.kotlin.descriptors.impl.MutablePackageFragmentDescriptor
 import org.jetbrains.kotlin.name.ClassId
@@ -28,7 +29,7 @@ abstract class DeserializerForDecompilerBase(val directoryPackageFqName: FqName)
 
     protected val moduleDescriptor: ModuleDescriptorImpl = createDummyModule("module for building decompiled sources")
 
-    protected val packageFragmentProvider: PackageFragmentProvider = object : PackageFragmentProvider {
+    protected val packageFragmentProvider: PackageFragmentProvider = object : PackageFragmentProviderOptimized {
         override fun collectPackageFragments(fqName: FqName, packageFragments: MutableCollection<PackageFragmentDescriptor>) {
             packageFragments.add(createDummyPackageFragment(fqName))
         }

native/commonizer/src/org/jetbrains/kotlin/descriptors/commonizer/builder/CommonizedPackageFragmentProvider.kt

@@ -7,10 +7,11 @@ package org.jetbrains.kotlin.descriptors.commonizer.builder
 
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentProvider
+import org.jetbrains.kotlin.descriptors.PackageFragmentProviderOptimized
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 
-internal class CommonizedPackageFragmentProvider : PackageFragmentProvider {
+internal class CommonizedPackageFragmentProvider : PackageFragmentProviderOptimized {
     private val packageFragments = ArrayList<PackageFragmentDescriptor>()
 
     operator fun plusAssign(packageFragment: PackageFragmentDescriptor) {

plugins/android-extensions/android-extensions-compiler/src/org/jetbrains/kotlin/android/synthetic/res/AndroidPackageFragmentProviderExtension.kt

@@ -28,6 +28,7 @@ import org.jetbrains.kotlin.android.synthetic.forEachUntilLast
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
 import org.jetbrains.kotlin.descriptors.PackageFragmentProvider
+import org.jetbrains.kotlin.descriptors.PackageFragmentProviderOptimized
 import org.jetbrains.kotlin.incremental.components.LookupTracker
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
@@ -132,7 +133,7 @@ abstract class AndroidPackageFragmentProviderExtension : PackageFragmentProvider
 
 class AndroidSyntheticPackageFragmentProvider(
     val packages: Map<FqName, () -> PackageFragmentDescriptor>
-) : PackageFragmentProvider {
+) : PackageFragmentProviderOptimized {
     override fun collectPackageFragments(fqName: FqName, packageFragments: MutableCollection<PackageFragmentDescriptor>) =
         packageFragments.addIfNotNull(packages[fqName]?.invoke())