From a20ce0610276a21acf8f54f8bafa34560019f8c8 Mon Sep 17 00:00:00 2001
From: Leonid Startsev <leonid.startsev@jetbrains.com>
Date: Thu, 22 Sep 2022 18:29:06 +0200
Subject: [PATCH] Support @Serializable(ContextualSerializer) on class

It was fixed some time ago (https://github.com/Kotlin/kotlinx.serialization/issues/957)
but for some reason only for old backend.

Fixes https://github.com/Kotlin/kotlinx.serialization/issues/1776
---
 .../compiler/backend/ir/BaseIrGenerator.kt       |  1 +
 .../testData/boxIr/contextualByDefault.kt        | 16 ++++++++++++++++
 .../SerializationFirBlackBoxTestGenerated.java   |  6 ++++++
 .../runners/SerializationIrBoxTestGenerated.java |  6 ++++++
 4 files changed, 29 insertions(+)
 create mode 100644 plugins/kotlinx-serialization/testData/boxIr/contextualByDefault.kt

diff --git a/plugins/kotlinx-serialization/kotlinx-serialization.backend/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/BaseIrGenerator.kt b/plugins/kotlinx-serialization/kotlinx-serialization.backend/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/BaseIrGenerator.kt
index dc7259913ec..d4c5b47bb67 100644
--- a/plugins/kotlinx-serialization/kotlinx-serialization.backend/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/BaseIrGenerator.kt
+++ b/plugins/kotlinx-serialization/kotlinx-serialization.backend/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/BaseIrGenerator.kt
@@ -403,6 +403,7 @@ abstract class BaseIrGenerator(private val currentClass: IrClass, final override
                     // new signature of context serializer
                     args = args + mutableListOf<IrExpression>().apply {
                         val fallbackDefaultSerializer = findTypeSerializer(pluginContext, kType)
+                            .takeIf { it?.owner?.classId != contextSerializerId }
                         add(instantiate(fallbackDefaultSerializer, kType) ?: irNull())
                         add(
                             createArrayOfExpression(
diff --git a/plugins/kotlinx-serialization/testData/boxIr/contextualByDefault.kt b/plugins/kotlinx-serialization/testData/boxIr/contextualByDefault.kt
new file mode 100644
index 00000000000..e9412fefe38
--- /dev/null
+++ b/plugins/kotlinx-serialization/testData/boxIr/contextualByDefault.kt
@@ -0,0 +1,16 @@
+// TARGET_BACKEND: JVM_IR
+
+// WITH_STDLIB
+
+import kotlinx.serialization.*
+
+@Serializable(with = ContextualSerializer::class)
+class Ref(
+    val id: String,
+)
+
+fun box(): String {
+    val kind = Ref.serializer().descriptor.kind.toString()
+    if (kind != "CONTEXTUAL") return kind
+    return "OK"
+}
\ No newline at end of file
diff --git a/plugins/kotlinx-serialization/tests-gen/org/jetbrains/kotlinx/serialization/runners/SerializationFirBlackBoxTestGenerated.java b/plugins/kotlinx-serialization/tests-gen/org/jetbrains/kotlinx/serialization/runners/SerializationFirBlackBoxTestGenerated.java
index 22483070c47..fe56f076125 100644
--- a/plugins/kotlinx-serialization/tests-gen/org/jetbrains/kotlinx/serialization/runners/SerializationFirBlackBoxTestGenerated.java
+++ b/plugins/kotlinx-serialization/tests-gen/org/jetbrains/kotlinx/serialization/runners/SerializationFirBlackBoxTestGenerated.java
@@ -39,6 +39,12 @@ public class SerializationFirBlackBoxTestGenerated extends AbstractSerialization
             runTest("plugins/kotlinx-serialization/testData/boxIr/classSerializerAsObject.kt");
         }
 
+        @Test
+        @TestMetadata("contextualByDefault.kt")
+        public void testContextualByDefault() throws Exception {
+            runTest("plugins/kotlinx-serialization/testData/boxIr/contextualByDefault.kt");
+        }
+
         @Test
         @TestMetadata("enumsAreCached.kt")
         public void testEnumsAreCached() throws Exception {
diff --git a/plugins/kotlinx-serialization/tests-gen/org/jetbrains/kotlinx/serialization/runners/SerializationIrBoxTestGenerated.java b/plugins/kotlinx-serialization/tests-gen/org/jetbrains/kotlinx/serialization/runners/SerializationIrBoxTestGenerated.java
index b054f5e735a..2425cdec948 100644
--- a/plugins/kotlinx-serialization/tests-gen/org/jetbrains/kotlinx/serialization/runners/SerializationIrBoxTestGenerated.java
+++ b/plugins/kotlinx-serialization/tests-gen/org/jetbrains/kotlinx/serialization/runners/SerializationIrBoxTestGenerated.java
@@ -37,6 +37,12 @@ public class SerializationIrBoxTestGenerated extends AbstractSerializationIrBoxT
         runTest("plugins/kotlinx-serialization/testData/boxIr/classSerializerAsObject.kt");
     }
 
+    @Test
+    @TestMetadata("contextualByDefault.kt")
+    public void testContextualByDefault() throws Exception {
+        runTest("plugins/kotlinx-serialization/testData/boxIr/contextualByDefault.kt");
+    }
+
     @Test
     @TestMetadata("enumsAreCached.kt")
     public void testEnumsAreCached() throws Exception {