grpc-pb: Add InvalidProtobufError class

Signed-off-by: Johannes Zottele <[email protected]>

Author: Jozott00

grpc/grpc-core/src/commonMain/kotlin/kotlinx/rpc/grpc/GrpcError.kt

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2023-2025 JetBrains s.r.o and contributors. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package kotlinx.rpc.grpc
+
+public sealed class GrpcError : RuntimeException {
+    protected constructor(message: String) : super(message)
+    protected constructor(message: String, cause: Throwable) : super(message, cause)
+}
+
+
+public class InvalidProtobufError(message: String) : GrpcError(message) {
+    public companion object {
+        internal fun missingRequiredField(messageName: String, fieldName: String) =
+            InvalidProtobufError("Message '$messageName' is missing a required field: $fieldName")
+    }
+}
+

grpc/grpc-core/src/commonTest/kotlin/kotlinx/rpc/grpc/pb/ProtosTest.kt

@@ -13,6 +13,7 @@ import asInternal
 import encodeWith
 import invoke
 import kotlinx.io.Buffer
+import kotlinx.rpc.grpc.InvalidProtobufError
 import kotlinx.rpc.grpc.codec.MessageCodec
 import kotlinx.rpc.grpc.test.*
 import kotlinx.rpc.grpc.test.common.*
@@ -104,7 +105,7 @@ class ProtosTest {
 
     @Test
     fun testRepeatedWithRequiredSubField() {
-        assertFailsWith<IllegalStateException> {
+        assertFailsWith<InvalidProtobufError> {
             RepeatedWithRequired {
                 // we construct the message using the internal class,
                 // so it is not invoking the checkRequired method on construction
@@ -116,7 +117,7 @@ class ProtosTest {
     @Test
     fun testPresenceCheckProto() {
         // Check a missing required field in a user-constructed message
-        assertFailsWith<IllegalStateException> {
+        assertFailsWith<InvalidProtobufError> {
             PresenceCheck {}
         }
 
@@ -126,7 +127,7 @@ class ProtosTest {
         encoder.writeFloat(2, 1f)
         encoder.flush()
 
-        assertFailsWith<IllegalStateException> {
+        assertFailsWith<InvalidProtobufError> {
             PresenceCheckInternal.CODEC.decode(buffer)
         }
     }
@@ -245,7 +246,7 @@ class ProtosTest {
 
     @Test
     fun testOneOfRequiredSubField() {
-        assertFailsWith<IllegalStateException> {
+        assertFailsWith<InvalidProtobufError> {
             OneOfWithRequired {
                 // we construct the message using the internal class,
                 // so it is not invoking the checkRequired method on construction
@@ -276,7 +277,7 @@ class ProtosTest {
 
     @Test
     fun testRecursiveReqNotSet() {
-        assertFailsWith<IllegalStateException> {
+        assertFailsWith<InvalidProtobufError> {
             val msg = RecursiveReq {
                 rec = RecursiveReq {
                     rec = RecursiveReq {
@@ -397,7 +398,7 @@ class ProtosTest {
         // we use the internal constructor to avoid a "missing required field" error during object construction
         val missingRequiredMessage = PresenceCheckInternal()
 
-        assertFailsWith<IllegalStateException> {
+        assertFailsWith<InvalidProtobufError> {
             val msg = TestMap {
                 messages = mapOf(
                     2 to missingRequiredMessage

protoc-gen/src/main/kotlin/kotlinx/rpc/protobuf/ModelToKotlinCommonGenerator.kt

@@ -586,7 +586,7 @@ class ModelToKotlinCommonGenerator(
 
         requiredFields.forEach { field ->
             ifBranch(condition = "!presenceMask[${field.presenceIdx}]", ifBlock = {
-                code("error(\"${declaration.name.simpleName} is missing required field: ${field.name}\")")
+                code("throw kotlinx.rpc.grpc.InvalidProtobufError.missingRequiredField(\"${declaration.name.simpleName}\", \"${field.name}\")")
             })
         }