K2: fix exception in deserializer for external setter #KT-53031 Fixed

compiler/fir/fir-serialization/src/org/jetbrains/kotlin/fir/serialization/FirElementSerializer.kt

@@ -287,10 +287,7 @@ class FirElementSerializer private constructor(
             }
 
             val nonSourceAnnotations = setter.nonSourceAnnotations(session, property)
-            if (setter !is FirDefaultPropertyAccessor ||
+            if (Flags.IS_NOT_DEFAULT.get(accessorFlags)) {
-                nonSourceAnnotations.isNotEmpty() ||
-                setter.visibility != property.visibility
-            ) {
                 val setterLocal = local.createChildSerializer(setter)
                 for (valueParameterDescriptor in setter.valueParameters) {
                     val annotations = nonSourceAnnotations.filter { it.useSiteTarget == AnnotationUseSiteTarget.SETTER_PARAMETER }

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

@@ -17787,6 +17787,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/fir/ExtensionAlias.kt");
         }
 
+        @Test
+        @TestMetadata("externalInDependency.kt")
+        public void testExternalInDependency() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/externalInDependency.kt");
+        }
+
         @Test
         @TestMetadata("FakeOverrideBuilder.kt")
         public void testFakeOverrideBuilder() throws Exception {

compiler/testData/codegen/box/fir/externalInDependency.kt

@@ -0,0 +1,18 @@
+// TARGET_BACKEND: JVM_IR
+
+// MODULE: m1
+// FILE: f1.kt
+
+object O {
+    var prop: String
+        external get
+        external set
+}
+
+// MODULE: m2(m1)
+// FILE: f2.kt
+
+fun box(): String {
+    O.hashCode() // Necessary to deserialize O
+    return "OK"
+}

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

@@ -17787,6 +17787,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/fir/ExtensionAlias.kt");
         }
 
+        @Test
+        @TestMetadata("externalInDependency.kt")
+        public void testExternalInDependency() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/externalInDependency.kt");
+        }
+
         @Test
         @TestMetadata("FakeOverrideBuilder.kt")
         public void testFakeOverrideBuilder() throws Exception {