[FIR] Unregister java element finders from previous sessions

The problem here is that for common session we register `FirJavaElementFinder`
  which provides light classes based on expect classes. And then
  at the start of analysis of jvm module we register one another
  `FirJavaElementFinder`, which sees actual classes and uses them to
  build light classes

But, because class ids of expect and actual class pair are the same and
  element finders are ordered by creation order, when java resolve tries
  to resolve some class, it founds light class based on expect class,
  even if we are already in platform session

To fix this problem, it was decided to unregister all previous element
  finders on creation of each new session, so old finders won't interfere
  with analysis

^KT-63612 Fixed
^KT-64296

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirBlackBoxCodegenBasedTestGenerated.java

@@ -35247,6 +35247,12 @@ public class LLFirBlackBoxCodegenBasedTestGenerated extends AbstractLLFirBlackBo
                 runTest("compiler/testData/codegen/box/multiplatform/k2/internalOverride2.kt");
             }
 
+            @Test
+            @TestMetadata("javaClassReferencedActualType.kt")
+            public void testJavaClassReferencedActualType() throws Exception {
+                runTest("compiler/testData/codegen/box/multiplatform/k2/javaClassReferencedActualType.kt");
+            }
+
             @Test
             @TestMetadata("javaMethodWithTypeParameter.kt")
             public void testJavaMethodWithTypeParameter() throws Exception {

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirReversedBlackBoxCodegenBasedTestGenerated.java

@@ -35247,6 +35247,12 @@ public class LLFirReversedBlackBoxCodegenBasedTestGenerated extends AbstractLLFi
                 runTest("compiler/testData/codegen/box/multiplatform/k2/internalOverride2.kt");
             }
 
+            @Test
+            @TestMetadata("javaClassReferencedActualType.kt")
+            public void testJavaClassReferencedActualType() throws Exception {
+                runTest("compiler/testData/codegen/box/multiplatform/k2/javaClassReferencedActualType.kt");
+            }
+
             @Test
             @TestMetadata("javaMethodWithTypeParameter.kt")
             public void testJavaMethodWithTypeParameter() throws Exception {

compiler/cli/cli-base/src/org/jetbrains/kotlin/cli/jvm/compiler/KotlinCoreEnvironment.kt

@@ -799,7 +799,7 @@ class KotlinCoreEnvironment private constructor(
                 // exception from `ExtensionPointImpl.doRegisterExtension`, because the registered extension can no longer be found
                 // when the project is being disposed.
                 // For example, see the `unregisterExtension` call in `GenerationUtils.compileFilesUsingFrontendIR`.
-                // TODO: refactor this to avoid registering unneeded extensions in the first place, and avoid using deprecated API.
+                // TODO: refactor this to avoid registering unneeded extensions in the first place, and avoid using deprecated API. (KT-64296)
                 @Suppress("DEPRECATION")
                 PsiElementFinder.EP.getPoint(project).registerExtension(JavaElementFinder(this))
                 @Suppress("DEPRECATION")

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/VfsBasedProjectEnvironment.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.cli.jvm.compiler
 
+import com.intellij.openapi.extensions.ExtensionPoint
 import com.intellij.openapi.project.Project
 import com.intellij.openapi.vfs.StandardFileSystems
 import com.intellij.openapi.vfs.VirtualFile
@@ -66,13 +67,14 @@ open class VfsBasedProjectEnvironment(
     @OptIn(SessionConfiguration::class)
     override fun registerAsJavaElementFinder(firSession: FirSession) {
         val psiFinderExtensionPoint = PsiElementFinder.EP.getPoint(project)
-        if (psiFinderExtensionPoint.extensionList.any { it is JavaElementFinder }) {
-            psiFinderExtensionPoint.unregisterExtension(JavaElementFinder::class.java)
-        }
+        psiFinderExtensionPoint.unregisterFinders<JavaElementFinder>()
+        psiFinderExtensionPoint.unregisterFinders<FirJavaElementFinder>()
 
         val firJavaElementFinder = FirJavaElementFinder(firSession, project)
         firSession.register(FirJavaElementFinder::class, firJavaElementFinder)
-        psiFinderExtensionPoint.registerExtension(firJavaElementFinder, project)
+        // see comment and TODO in KotlinCoreEnvironment.registerKotlinLightClassSupport (KT-64296)
+        @Suppress("DEPRECATION")
+        PsiElementFinder.EP.getPoint(project).registerExtension(firJavaElementFinder)
     }
 
     private fun List<VirtualFile>.toSearchScope(allowOutOfProjectRoots: Boolean) =
@@ -152,3 +154,9 @@ fun KotlinCoreEnvironment.toAbstractProjectEnvironment(): AbstractProjectEnviron
 
 fun GlobalSearchScope.toAbstractProjectFileSearchScope(): AbstractProjectFileSearchScope =
     PsiBasedProjectFileSearchScope(this)
+
+inline fun <reified T : PsiElementFinder> ExtensionPoint<PsiElementFinder>.unregisterFinders() {
+    if (extensionList.any { it is T }) {
+        unregisterExtension(T::class.java)
+    }
+}

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirLightTreeBlackBoxCodegenTestGenerated.java

@@ -34828,6 +34828,12 @@ public class FirLightTreeBlackBoxCodegenTestGenerated extends AbstractFirLightTr
                 runTest("compiler/testData/codegen/box/multiplatform/k2/internalOverride2.kt");
             }
 
+            @Test
+            @TestMetadata("javaClassReferencedActualType.kt")
+            public void testJavaClassReferencedActualType() throws Exception {
+                runTest("compiler/testData/codegen/box/multiplatform/k2/javaClassReferencedActualType.kt");
+            }
+
             @Test
             @TestMetadata("javaMethodWithTypeParameter.kt")
             public void testJavaMethodWithTypeParameter() throws Exception {

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirLightTreeBlackBoxCodegenWithIrFakeOverrideGeneratorTestGenerated.java

@@ -34828,6 +34828,12 @@ public class FirLightTreeBlackBoxCodegenWithIrFakeOverrideGeneratorTestGenerated
                 runTest("compiler/testData/codegen/box/multiplatform/k2/internalOverride2.kt");
             }
 
+            @Test
+            @TestMetadata("javaClassReferencedActualType.kt")
+            public void testJavaClassReferencedActualType() throws Exception {
+                runTest("compiler/testData/codegen/box/multiplatform/k2/javaClassReferencedActualType.kt");
+            }
+
             @Test
             @TestMetadata("javaMethodWithTypeParameter.kt")
             public void testJavaMethodWithTypeParameter() throws Exception {

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirPsiBlackBoxCodegenTestGenerated.java

@@ -34828,6 +34828,12 @@ public class FirPsiBlackBoxCodegenTestGenerated extends AbstractFirPsiBlackBoxCo
                 runTest("compiler/testData/codegen/box/multiplatform/k2/internalOverride2.kt");
             }
 
+            @Test
+            @TestMetadata("javaClassReferencedActualType.kt")
+            public void testJavaClassReferencedActualType() throws Exception {
+                runTest("compiler/testData/codegen/box/multiplatform/k2/javaClassReferencedActualType.kt");
+            }
+
             @Test
             @TestMetadata("javaMethodWithTypeParameter.kt")
             public void testJavaMethodWithTypeParameter() throws Exception {

compiler/testData/codegen/box/multiplatform/k2/javaClassReferencedActualType.kt

@@ -0,0 +1,37 @@
+// LANGUAGE: +MultiPlatformProjects
+// IGNORE_BACKEND_K1: ANY
+// TARGET_BACKEND: JVM_IR
+
+// MODULE: common
+// FILE: Base.kt
+expect interface Base
+
+// MODULE: jvm()()(common)
+// FILE: Property.kt
+public actual interface Base {
+    fun getValue(): PropType // /Base.PropType
+
+    interface PropType {
+        val name: String
+    }
+}
+
+// FILE: Derived.java
+public abstract class Derived implements Base {
+    @Override
+    public Base.PropType getValue() { // /Base/PropType
+        return new Base.PropType() {
+            @Override
+            public String getName() {
+                return "OK";
+            }
+        };
+    }
+}
+
+// FILE: main.kt
+class Impl : Derived()
+
+fun box(): String {
+    return Impl().value.name
+}

compiler/tests-common-new/tests/org/jetbrains/kotlin/test/frontend/fir/FirFrontendFacade.kt

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.asJava.finder.JavaElementFinder
 import org.jetbrains.kotlin.cli.jvm.compiler.PsiBasedProjectFileSearchScope
 import org.jetbrains.kotlin.cli.jvm.compiler.TopDownAnalyzerFacadeForJVM
 import org.jetbrains.kotlin.cli.jvm.compiler.VfsBasedProjectEnvironment
+import org.jetbrains.kotlin.cli.jvm.compiler.unregisterFinders
 import org.jetbrains.kotlin.cli.jvm.config.jvmClasspathRoots
 import org.jetbrains.kotlin.cli.jvm.config.jvmModularRoots
 import org.jetbrains.kotlin.config.CompilerConfiguration
@@ -278,7 +279,7 @@ open class FirFrontendFacade(
 
         val project = compilerConfigurationProvider.getProject(module)
 
-        PsiElementFinder.EP.getPoint(project).unregisterExtension(JavaElementFinder::class.java)
+        PsiElementFinder.EP.getPoint(project).unregisterFinders<JavaElementFinder>()
 
         val parser = module.directives.singleValue(FirDiagnosticsDirectives.FIR_PARSER)