Add value class support to the ProtoBufSchemaGenerator (#2542)

Fixes #2089

Author: rotilho

formats/protobuf/commonMain/src/kotlinx/serialization/protobuf/schema/ProtoBufSchemaGenerator.kt

@@ -216,29 +216,34 @@ public object ProtoBufSchemaGenerator {
         val messageDescriptor = messageType.descriptor
 
         val fieldDescriptor = messageDescriptor.getElementDescriptor(index)
+        var unwrappedFieldDescriptor = fieldDescriptor
+        while (unwrappedFieldDescriptor.isInline) {
+            unwrappedFieldDescriptor = unwrappedFieldDescriptor.getElementDescriptor(0)
+        }
+
         val nestedTypes: List<TypeDefinition>
         val typeName: String = when {
             messageDescriptor.isSealedPolymorphic && index == 1 -> {
                 appendLine("  // decoded as message with one of these types:")
-                nestedTypes = fieldDescriptor.elementDescriptors.map { TypeDefinition(it) }.toList()
+                nestedTypes = unwrappedFieldDescriptor.elementDescriptors.map { TypeDefinition(it) }.toList()
                 nestedTypes.forEachIndexed { _, childType ->
                     append("  //   message ").append(childType.descriptor.messageOrEnumName).append(", serial name '")
                         .append(removeLineBreaks(childType.descriptor.serialName)).appendLine('\'')
                 }
-                fieldDescriptor.scalarTypeName()
+                unwrappedFieldDescriptor.scalarTypeName()
             }
-            fieldDescriptor.isProtobufScalar -> {
+            unwrappedFieldDescriptor.isProtobufScalar -> {
                 nestedTypes = emptyList()
-                fieldDescriptor.scalarTypeName(messageDescriptor.getElementAnnotations(index))
+                unwrappedFieldDescriptor.scalarTypeName(messageDescriptor.getElementAnnotations(index))
             }
-            fieldDescriptor.isOpenPolymorphic -> {
+            unwrappedFieldDescriptor.isOpenPolymorphic -> {
                 nestedTypes = listOf(SyntheticPolymorphicType)
                 SyntheticPolymorphicType.descriptor.serialName
             }
             else -> {
                 // enum or regular message
-                nestedTypes = listOf(TypeDefinition(fieldDescriptor))
-                fieldDescriptor.messageOrEnumName
+                nestedTypes = listOf(TypeDefinition(unwrappedFieldDescriptor))
+                unwrappedFieldDescriptor.messageOrEnumName
             }
         }
 

formats/protobuf/jvmTest/resources/OptionalClass.proto

@@ -5,9 +5,21 @@ package kotlinx.serialization.protobuf.schema.generator;
 // serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.OptionalClass'
 message OptionalClass {
   required int32 requiredInt = 1;
+  required int32 requiredUInt = 2;
+  required int32 requiredWrappedUInt = 3;
   // WARNING: a default value decoded when value is missing
-  optional int32 optionalInt = 2;
-  optional int32 nullableInt = 3;
+  optional int32 optionalInt = 4;
   // WARNING: a default value decoded when value is missing
-  optional int32 nullableOptionalInt = 4;
+  optional int32 optionalUInt = 5;
+  // WARNING: a default value decoded when value is missing
+  optional int32 optionalWrappedUInt = 6;
+  optional int32 nullableInt = 7;
+  optional int32 nullableUInt = 8;
+  optional int32 nullableWrappedUInt = 9;
+  // WARNING: a default value decoded when value is missing
+  optional int32 nullableOptionalInt = 10;
+  // WARNING: a default value decoded when value is missing
+  optional int32 nullableOptionalUInt = 11;
+  // WARNING: a default value decoded when value is missing
+  optional int32 nullableOptionalWrappedUInt = 12;
 }

formats/protobuf/jvmTest/resources/common/schema.proto

@@ -63,11 +63,23 @@ message MapClass {
 // serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.OptionalClass'
 message OptionalClass {
   required int32 requiredInt = 1;
+  required int32 requiredUInt = 2;
+  required int32 requiredWrappedUInt = 3;
   // WARNING: a default value decoded when value is missing
-  optional int32 optionalInt = 2;
-  optional int32 nullableInt = 3;
+  optional int32 optionalInt = 4;
   // WARNING: a default value decoded when value is missing
-  optional int32 nullableOptionalInt = 4;
+  optional int32 optionalUInt = 5;
+  // WARNING: a default value decoded when value is missing
+  optional int32 optionalWrappedUInt = 6;
+  optional int32 nullableInt = 7;
+  optional int32 nullableUInt = 8;
+  optional int32 nullableWrappedUInt = 9;
+  // WARNING: a default value decoded when value is missing
+  optional int32 nullableOptionalInt = 10;
+  // WARNING: a default value decoded when value is missing
+  optional int32 nullableOptionalUInt = 11;
+  // WARNING: a default value decoded when value is missing
+  optional int32 nullableOptionalWrappedUInt = 12;
 }
 
 // serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.ContextualHolder'

formats/protobuf/jvmTest/src/kotlinx/serialization/protobuf/schema/GenerationTest.kt

@@ -61,7 +61,7 @@ class GenerationTest {
         @ProtoNumber(5)
         val b: Int,
         @ProtoNumber(3)
-        val c: Int
+        val c: UInt,
     )
 
     @Serializable
@@ -84,6 +84,10 @@ class GenerationTest {
     @Serializable
     data class OptionsClass(val i: Int)
 
+    @JvmInline
+    @Serializable
+    value class WrappedUInt(val i : UInt)
+
     @Serializable
     class ListClass(
         val intList: List<Int>,
@@ -113,9 +117,17 @@ class GenerationTest {
     @Serializable
     data class OptionalClass(
         val requiredInt: Int,
+        val requiredUInt: UInt,
+        val requiredWrappedUInt: WrappedUInt,
         val optionalInt: Int = 5,
+        val optionalUInt: UInt = 5U,
+        val optionalWrappedUInt: WrappedUInt = WrappedUInt(5U),
         val nullableInt: Int?,
-        val nullableOptionalInt: Int? = 10
+        val nullableUInt: UInt?,
+        val nullableWrappedUInt: WrappedUInt?,
+        val nullableOptionalInt: Int? = 10,
+        val nullableOptionalUInt: UInt? = 10U,
+        val nullableOptionalWrappedUInt: WrappedUInt? = WrappedUInt(10U),
     )
 
     @Serializable