Correctly handle @Repeatable @SerialInfo annotations on classes

that were affected by deduplication of inherited serial info annotations.

Prohibit combination of @InheritableSerialInfo and @Repeatable.

Fixes https://github.com/Kotlin/kotlinx.serialization/issues/2099

plugins/kotlinx-serialization/kotlinx-serialization.k1/src/org/jetbrains/kotlinx/serialization/compiler/diagnostic/SerializationErrors.java

@@ -54,6 +54,8 @@ public interface SerializationErrors {
     DiagnosticFactory2<PsiElement, KotlinType, KotlinType> INCONSISTENT_INHERITABLE_SERIALINFO = DiagnosticFactory2.create(ERROR);
     DiagnosticFactory0<PsiElement> META_SERIALIZABLE_NOT_APPLICABLE = DiagnosticFactory0.create(WARNING);
 
+    DiagnosticFactory0<PsiElement> INHERITABLE_SERIALINFO_CANT_BE_REPEATABLE = DiagnosticFactory0.create(ERROR);
+
     DiagnosticFactory1<PsiElement, KotlinType> EXTERNAL_SERIALIZER_USELESS = DiagnosticFactory1.create(WARNING);
 
     DiagnosticFactory2<PsiElement, KotlinType, KotlinType> EXTERNAL_CLASS_NOT_SERIALIZABLE = DiagnosticFactory2.create(ERROR);

plugins/kotlinx-serialization/kotlinx-serialization.k1/src/org/jetbrains/kotlinx/serialization/compiler/diagnostic/SerializationPluginDeclarationChecker.kt

@@ -15,6 +15,7 @@ import org.jetbrains.kotlin.descriptors.annotations.Annotations
 import org.jetbrains.kotlin.diagnostics.DiagnosticFactory0
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.js.resolve.diagnostics.findPsi
+import org.jetbrains.kotlin.load.java.JvmAnnotationNames
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.JvmNames.TRANSIENT_ANNOTATION_FQ_NAME
 import org.jetbrains.kotlin.psi.*
@@ -47,6 +48,7 @@ open class SerializationPluginDeclarationChecker : DeclarationChecker {
         if (descriptor !is ClassDescriptor) return
 
         checkMetaSerializableApplicable(descriptor, context.trace)
+        checkInheritableSerialInfoNotRepeatable(descriptor, context.trace)
         checkEnum(descriptor, declaration, context.trace)
         checkExternalSerializer(descriptor, declaration, context.trace)
 
@@ -74,6 +76,14 @@ open class SerializationPluginDeclarationChecker : DeclarationChecker {
         trace.report(SerializationErrors.META_SERIALIZABLE_NOT_APPLICABLE.on(entry))
     }
 
+    private fun checkInheritableSerialInfoNotRepeatable(descriptor: ClassDescriptor, trace: BindingTrace) {
+        if (descriptor.kind != ClassKind.ANNOTATION_CLASS) return
+        // both kotlin.Repeatable and java.lang.annotation.Repeatable
+        if (!(descriptor.isAnnotatedWithKotlinRepeatable() || descriptor.annotations.hasAnnotation(JvmAnnotationNames.REPEATABLE_ANNOTATION))) return
+        val inheritableAnno = descriptor.findAnnotationDeclaration(SerializationAnnotations.inheritableSerialInfoFqName) ?: return
+        trace.report(SerializationErrors.INHERITABLE_SERIALINFO_CANT_BE_REPEATABLE.on(inheritableAnno))
+    }
+
     private fun checkExternalSerializer(classDescriptor: ClassDescriptor, declaration: KtDeclaration, trace: BindingTrace) {
         val serializableKType = classDescriptor.serializerForClass ?: return
         val serializableDescriptor = serializableKType.toClassDescriptor ?: return

plugins/kotlinx-serialization/kotlinx-serialization.k1/src/org/jetbrains/kotlinx/serialization/compiler/diagnostic/SerializationPluginErrorsRendering.kt

@@ -164,6 +164,10 @@ object SerializationPluginErrorsRendering : DefaultErrorMessages.Extension {
             SerializationErrors.META_SERIALIZABLE_NOT_APPLICABLE,
             "@MetaSerializable annotation should be used only on top-level annotation classes. Usage on nested annotation classes is deprecated and will yield errors in the future."
         )
+        MAP.put(
+           SerializationErrors.INHERITABLE_SERIALINFO_CANT_BE_REPEATABLE,
+           "Repeatable serial info annotations can not be inheritable. Either remove @Repeatable or use a regular @SerialInfo annotation."
+        )
 
         MAP.put(
             SerializationErrors.EXTERNAL_SERIALIZER_USELESS,