JVM, JVM IR: report error if not all parts of multifile class are @JvmSynthetic

#KT-41884 Fixed

compiler/backend/src/org/jetbrains/kotlin/codegen/MultifileClassCodegen.kt

@@ -34,9 +34,13 @@ import org.jetbrains.kotlin.psi.KtClassOrObject
 import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi.KtTypeAlias
 import org.jetbrains.kotlin.resolve.BindingContext
+import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.MemberComparator
+import org.jetbrains.kotlin.resolve.descriptorUtil.annotationClass
 import org.jetbrains.kotlin.resolve.jvm.AsmTypes
 import org.jetbrains.kotlin.resolve.jvm.JvmClassName
+import org.jetbrains.kotlin.resolve.jvm.annotations.JVM_SYNTHETIC_ANNOTATION_FQ_NAME
+import org.jetbrains.kotlin.resolve.jvm.diagnostics.ErrorsJvm
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.MultifileClass
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.MultifileClassPart
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.OtherOrigin
@@ -125,8 +129,19 @@ class MultifileClassCodegenImpl(
         val superClassForFacade = if (shouldGeneratePartHierarchy) partInternalNamesSorted.last() else J_L_OBJECT
 
         state.factory.newVisitor(MultifileClass(files.firstOrNull(), actualPackageFragment), facadeClassType, files).apply {
+            var attributes = FACADE_CLASS_ATTRIBUTES
+
+            val nonJvmSyntheticParts = files.filterNot { it.isJvmSynthetic() }
+            if (nonJvmSyntheticParts.isEmpty()) {
+                attributes = attributes or Opcodes.ACC_SYNTHETIC
+            } else if (nonJvmSyntheticParts.size < files.size) {
+                for (part in nonJvmSyntheticParts) {
+                    state.diagnostics.report(ErrorsJvm.NOT_ALL_MULTIFILE_CLASS_PARTS_ARE_JVM_SYNTHETIC.on(part.packageDirective ?: part))
+                }
+            }
+
             defineClass(
-                singleSourceFile, state.classFileVersion, FACADE_CLASS_ATTRIBUTES,
+                singleSourceFile, state.classFileVersion, attributes,
                 facadeClassType.internalName, null, superClassForFacade, emptyArray()
             )
             if (singleSourceFile != null) {
@@ -146,6 +161,13 @@ class MultifileClassCodegenImpl(
         }
     }
 
+    private fun KtFile.isJvmSynthetic(): Boolean {
+        return annotationEntries.any { entry ->
+            val descriptor = state.bindingContext[BindingContext.ANNOTATION, entry]
+            descriptor?.annotationClass?.let(DescriptorUtils::getFqNameSafe) == JVM_SYNTHETIC_ANNOTATION_FQ_NAME
+        }
+    }
+
     override fun generate() {
         assert(delegateGenerationTasks.isEmpty()) { "generate() is called twice for facade class $facadeFqName" }
 

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/diagnostics/DefaultErrorMessagesJvm.java

@@ -78,6 +78,7 @@ public class DefaultErrorMessagesJvm implements DefaultErrorMessages.Extension {
         MAP.put(JVM_PACKAGE_NAME_NOT_SUPPORTED_IN_FILES_WITH_CLASSES, "''@JvmPackageName'' annotation is not supported for files with class declarations");
 
         MAP.put(STATE_IN_MULTIFILE_CLASS, "Non-const property with backing field or delegate is not allowed in a multi-file class if -Xmultifile-parts-inherit is enabled");
+        MAP.put(NOT_ALL_MULTIFILE_CLASS_PARTS_ARE_JVM_SYNTHETIC, "All of multi-file class parts should be annotated with @JvmSynthetic if at least one of them is");
 
         MAP.put(NO_REFLECTION_IN_CLASS_PATH, "Call uses reflection API which is not found in compilation classpath. " +
                                              "Make sure you have kotlin-reflect.jar in the classpath");

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/diagnostics/ErrorsJvm.java

@@ -74,6 +74,7 @@ public interface ErrorsJvm {
     DiagnosticFactory0<KtAnnotationEntry> JVM_PACKAGE_NAME_NOT_SUPPORTED_IN_FILES_WITH_CLASSES = DiagnosticFactory0.create(ERROR);
 
     DiagnosticFactory0<KtDeclaration> STATE_IN_MULTIFILE_CLASS = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory0<PsiElement> NOT_ALL_MULTIFILE_CLASS_PARTS_ARE_JVM_SYNTHETIC = DiagnosticFactory0.create(ERROR);
 
     DiagnosticFactory0<PsiElement> INTERFACE_CANT_CALL_DEFAULT_METHOD_VIA_SUPER = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<PsiElement> SUBCLASS_CANT_CALL_COMPANION_PROTECTED_NON_STATIC = DiagnosticFactory0.create(ERROR);

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/GenerateMultifileFacades.kt

@@ -17,6 +17,7 @@ import org.jetbrains.kotlin.backend.common.phaser.makeCustomPhase
 import org.jetbrains.kotlin.backend.jvm.JvmBackendContext
 import org.jetbrains.kotlin.backend.jvm.JvmLoweredDeclarationOrigin
 import org.jetbrains.kotlin.backend.jvm.codegen.fileParent
+import org.jetbrains.kotlin.backend.jvm.ir.getKtFile
 import org.jetbrains.kotlin.config.JvmAnalysisFlags
 import org.jetbrains.kotlin.descriptors.DescriptorVisibilities
 import org.jetbrains.kotlin.descriptors.Modality
@@ -42,6 +43,8 @@ import org.jetbrains.kotlin.ir.visitors.transformChildrenVoid
 import org.jetbrains.kotlin.load.java.JavaDescriptorVisibilities
 import org.jetbrains.kotlin.resolve.inline.INLINE_ONLY_ANNOTATION_FQ_NAME
 import org.jetbrains.kotlin.resolve.jvm.JvmClassName
+import org.jetbrains.kotlin.resolve.jvm.annotations.JVM_SYNTHETIC_ANNOTATION_FQ_NAME
+import org.jetbrains.kotlin.resolve.jvm.diagnostics.ErrorsJvm
 
 internal val generateMultifileFacadesPhase = makeCustomPhase<JvmBackendContext, IrModuleFragment>(
     name = "GenerateMultifileFacades",
@@ -133,7 +136,22 @@ private fun generateMultifileFacades(
                     }
                 }
             }
+
+            val nonJvmSyntheticParts = partClasses.filterNot { it.hasAnnotation(JVM_SYNTHETIC_ANNOTATION_FQ_NAME) }
+            if (nonJvmSyntheticParts.isEmpty()) {
+                annotations = annotations + partClasses.first().getAnnotation(JVM_SYNTHETIC_ANNOTATION_FQ_NAME)!!.deepCopyWithSymbols()
+            } else if (nonJvmSyntheticParts.size < partClasses.size) {
+                for (part in nonJvmSyntheticParts) {
+                    val partFile = part.fileParent.getKtFile() ?: error("Not a KtFile: ${part.render()} ${part.fileParent}")
+                    // If at least one of parts is annotated with @JvmSynthetic, then all other parts should also be annotated.
+                    // We report this error on the package directive for each non-@JvmSynthetic part.
+                    context.state.diagnostics.report(
+                        ErrorsJvm.NOT_ALL_MULTIFILE_CLASS_PARTS_ARE_JVM_SYNTHETIC.on(partFile.packageDirective ?: partFile)
+                    )
+                }
+            }
         }
+
         file.declarations.add(facadeClass)
 
         for (partClass in partClasses) {

compiler/testData/codegen/bytecodeListing/multifileClasses/jvmSynthetic.kt

@@ -0,0 +1,18 @@
+// WITH_RUNTIME
+// FILE: f.kt
+
+@file:JvmName("Foo")
+@file:JvmMultifileClass
+@file:JvmSynthetic
+package test
+
+fun f() {}
+
+// FILE: g.kt
+
+@file:JvmName("Foo")
+@file:JvmMultifileClass
+@file:JvmSynthetic
+package test
+
+val g = ""

compiler/testData/codegen/bytecodeListing/multifileClasses/jvmSynthetic.txt

@@ -0,0 +1,19 @@
+@kotlin.Metadata
+public synthetic final class test/Foo {
+    public final static method f(): void
+    public final static @org.jetbrains.annotations.NotNull method getG(): java.lang.String
+}
+
+@kotlin.Metadata
+synthetic final class test/Foo__FKt {
+    // source: 'f.kt'
+    public final static method f(): void
+}
+
+@kotlin.Metadata
+synthetic final class test/Foo__GKt {
+    // source: 'g.kt'
+    private final static @org.jetbrains.annotations.NotNull field g: java.lang.String
+    static method <clinit>(): void
+    public final static @org.jetbrains.annotations.NotNull method getG(): java.lang.String
+}

compiler/testData/diagnostics/testsWithJvmBackend/multifileClasses/jvmSynthetic.kt

@@ -0,0 +1,33 @@
+// WITH_RUNTIME
+// FILE: f.kt
+
+@file:JvmName("Foo")
+@file:JvmMultifileClass
+<!NOT_ALL_MULTIFILE_CLASS_PARTS_ARE_JVM_SYNTHETIC!>package test<!>
+
+fun f() {}
+
+// FILE: g.kt
+
+@file:JvmName("Foo")
+@file:JvmMultifileClass
+@file:JvmSynthetic
+package test
+
+val g = ""
+
+// FILE: h.kt
+
+@file:JvmName("Foo")
+@file:JvmMultifileClass
+<!NOT_ALL_MULTIFILE_CLASS_PARTS_ARE_JVM_SYNTHETIC!>package test<!>
+
+fun h() {}
+
+// FILE: z.kt
+
+@file:JvmName("Bar")
+@file:JvmMultifileClass
+package test
+
+fun z() {}

compiler/testData/diagnostics/testsWithJvmBackend/multifileClasses/jvmSynthetic.txt

@@ -0,0 +1,8 @@
+package
+
+package test {
+    public val g: kotlin.String = ""
+    public fun f(): kotlin.Unit
+    public fun h(): kotlin.Unit
+    public fun z(): kotlin.Unit
+}

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticsTestWithJvmIrBackendGenerated.java

@@ -641,6 +641,22 @@ public class DiagnosticsTestWithJvmIrBackendGenerated extends AbstractDiagnostic
         }
     }
 
+    @Nested
+    @TestMetadata("compiler/testData/diagnostics/testsWithJvmBackend/multifileClasses")
+    @TestDataPath("$PROJECT_ROOT")
+    public class MultifileClasses {
+        @Test
+        public void testAllFilesPresentInMultifileClasses() throws Exception {
+            KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/testsWithJvmBackend/multifileClasses"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM_IR, true);
+        }
+
+        @Test
+        @TestMetadata("jvmSynthetic.kt")
+        public void testJvmSynthetic() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithJvmBackend/multifileClasses/jvmSynthetic.kt");
+        }
+    }
+
     @Nested
     @TestMetadata("compiler/testData/diagnostics/testsWithJvmBackend/valueClasses")
     @TestDataPath("$PROJECT_ROOT")

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticsTestWithOldJvmBackendGenerated.java

@@ -629,6 +629,22 @@ public class DiagnosticsTestWithOldJvmBackendGenerated extends AbstractDiagnosti
         }
     }
 
+    @Nested
+    @TestMetadata("compiler/testData/diagnostics/testsWithJvmBackend/multifileClasses")
+    @TestDataPath("$PROJECT_ROOT")
+    public class MultifileClasses {
+        @Test
+        public void testAllFilesPresentInMultifileClasses() throws Exception {
+            KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/testsWithJvmBackend/multifileClasses"), Pattern.compile("^(.+)\\.kt$"), null, TargetBackend.JVM_OLD, true);
+        }
+
+        @Test
+        @TestMetadata("jvmSynthetic.kt")
+        public void testJvmSynthetic() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithJvmBackend/multifileClasses/jvmSynthetic.kt");
+        }
+    }
+
     @Nested
     @TestMetadata("compiler/testData/diagnostics/testsWithJvmBackend/valueClasses")
     @TestDataPath("$PROJECT_ROOT")

compiler/tests-gen/org/jetbrains/kotlin/codegen/BytecodeListingTestGenerated.java

@@ -1548,6 +1548,11 @@ public class BytecodeListingTestGenerated extends AbstractBytecodeListingTest {
             runTest("compiler/testData/codegen/bytecodeListing/multifileClasses/emptyMultifileFacade.kt");
         }
 
+        @TestMetadata("jvmSynthetic.kt")
+        public void testJvmSynthetic() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeListing/multifileClasses/jvmSynthetic.kt");
+        }
+
         @TestMetadata("kt43519.kt")
         public void testKt43519() throws Exception {
             runTest("compiler/testData/codegen/bytecodeListing/multifileClasses/kt43519.kt");

compiler/tests-gen/org/jetbrains/kotlin/codegen/ir/IrBytecodeListingTestGenerated.java

@@ -1548,6 +1548,11 @@ public class IrBytecodeListingTestGenerated extends AbstractIrBytecodeListingTes
             runTest("compiler/testData/codegen/bytecodeListing/multifileClasses/emptyMultifileFacade.kt");
         }
 
+        @TestMetadata("jvmSynthetic.kt")
+        public void testJvmSynthetic() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeListing/multifileClasses/jvmSynthetic.kt");
+        }
+
         @TestMetadata("kt43519.kt")
         public void testKt43519() throws Exception {
             runTest("compiler/testData/codegen/bytecodeListing/multifileClasses/kt43519.kt");