Feature: Proto2 Language Support

buildSrc/build.gradle.kts

@@ -1,4 +1,3 @@
-
 plugins {
     `kotlin-dsl`
 }

kmp-grpc-core/src/androidJvmCommon/kotlin/io/github/timortel/kmpgrpc/core/message/Message.kt

@@ -11,6 +11,8 @@ actual interface Message {
 
     actual val fullName: String
 
+    actual val isInitialized: Boolean
+
     actual fun serialize(): ByteArray {
         val buffer = Buffer()
         serialize(CodedOutputStreamImpl(buffer))

kmp-grpc-core/src/commonMain/kotlin/io/github/timortel/kmpgrpc/core/UninitializedMessageException.kt

@@ -0,0 +1,21 @@
+package io.github.timortel.kmpgrpc.core
+
+import io.github.timortel.kmpgrpc.core.message.Message
+
+/**
+ * Thrown when a Protocol Buffers message is missing one or more required fields.
+ *
+ * In `proto2`, fields marked as `required` must be populated before a message
+ * can be fully initialized or serialized. This exception typically occurs during
+ * a DSL `build()` operation or when parsing a message that violates these
+ * presence constraints.
+ *
+ * @property msg The incomplete [Message] instance that triggered this exception.
+ * Note that accessing fields on this instance is safe, but it is considered
+ * semantically invalid according to the schema.
+ */
+class UninitializedMessageException(
+    val msg: Message,
+) : RuntimeException(
+    "Message ${msg::class.simpleName} is missing required fields."
+)

kmp-grpc-core/src/commonMain/kotlin/io/github/timortel/kmpgrpc/core/io/CodedInputStream.kt

@@ -64,6 +64,15 @@ abstract class CodedInputStream {
         return recursiveRead { deserializer.deserialize(this, extensionRegistry) }
     }
 
+    fun <M : Message> readGroup(deserializer: MessageDeserializer<M>, extensionRegistry: ExtensionRegistry<M>, fieldNumber: Int): M {
+        checkRecursionLimit()
+        recursionDepth++
+        val message = deserializer.deserialize(this, extensionRegistry)
+        checkLastTagWas(wireFormatMakeTag(fieldNumber, WireFormat.END_GROUP))
+        recursionDepth--
+        return message
+    }
+
     abstract fun readBytes(): ByteArray
 
     abstract fun readUInt32(): UInt
@@ -89,6 +98,7 @@ abstract class CodedInputStream {
         extensionRegistry: ExtensionRegistry<M>
     ): UnknownFieldOrExtension<M, Any>? {
         val number = wireFormatGetTagFieldNumber(tag)
+        if (wireFormatGetTagWireType(tag) == WireFormat.END_GROUP.value) return null
 
         val extension = extensionRegistry.getExtensionForFieldNumber(number)
         @Suppress("UNCHECKED_CAST")

kmp-grpc-core/src/commonMain/kotlin/io/github/timortel/kmpgrpc/core/io/CodedOutputStream.kt

@@ -77,8 +77,12 @@ interface CodedOutputStream {
 
     fun writeMessage(fieldNumber: Int, value: Message)
 
+    fun writeGroup(fieldNumber: Int, value: Message)
+
     fun writeMessageArray(fieldNumber: Int, values: List<Message>)
 
+    fun writeGroupArray(fieldNumber: Int, values: List<Message>)
+
     fun writeSFixed32(fieldNumber: Int, value: Int)
 
     fun writeSFixed32Array(fieldNumber: Int, values: List<Int>, tag: UInt)

kmp-grpc-core/src/commonMain/kotlin/io/github/timortel/kmpgrpc/core/io/internal/CodedOutputStreamImpl.kt

@@ -217,6 +217,16 @@ internal class CodedOutputStreamImpl(private val sink: Sink) : CodedOutputStream
         values.forEach { writeMessage(fieldNumber, it) }
     }
 
+    override fun writeGroup(fieldNumber: Int, value: Message) {
+        writeTag(fieldNumber, WireFormat.START_GROUP)
+        value.serialize(this)
+        writeTag(fieldNumber, WireFormat.END_GROUP)
+    }
+
+    override fun writeGroupArray(fieldNumber: Int, values: List<Message>) {
+        values.forEach { writeGroup(fieldNumber, it) }
+    }
+
     override fun <K, V> writeMap(
         fieldNumber: Int,
         map: Map<K, V>,

kmp-grpc-core/src/commonMain/kotlin/io/github/timortel/kmpgrpc/core/message/Message.kt

@@ -17,6 +17,11 @@ expect interface Message {
      */
     val fullName: String
 
+    /**
+     * If all required fields for this message have been set.
+     */
+    val isInitialized: Boolean
+
     /**
      * Serializes this message and returns it as a [ByteArray].
      *

kmp-grpc-core/src/commonMain/kotlin/io/github/timortel/kmpgrpc/core/message/util.kt

@@ -9,7 +9,7 @@ fun <M : Message> mergeUnknownFieldOrExtension(
     fieldOrExtension: UnknownFieldOrExtension<M, Any>?,
     unknownFields: MutableList<UnknownField>,
     extensionBuilder: MessageExtensionsBuilder<M>
-) {
+): Boolean {
     when (fieldOrExtension) {
         is UnknownFieldOrExtension.UnknownField -> unknownFields.add(fieldOrExtension.field)
         is UnknownFieldOrExtension.RepeatedExtension<M, Any> -> {
@@ -18,6 +18,8 @@ fun <M : Message> mergeUnknownFieldOrExtension(
         is UnknownFieldOrExtension.ScalarExtension<M, Any> -> {
             extensionBuilder[fieldOrExtension.extension] = fieldOrExtension.value
         }
-        null -> {}
+        null -> return false
     }
+
+    return true
 }

kmp-grpc-core/src/jsTargetCommon/kotlin/io/github/timortel/kmpgrpc/core/message/Message.kt

@@ -11,6 +11,8 @@ actual interface Message {
 
     actual val requiredSize: Int
 
+    actual val isInitialized: Boolean
+
     actual fun serialize(): ByteArray {
         val buffer = Buffer()
         serialize(CodedOutputStreamImpl(buffer))

kmp-grpc-core/src/nativeMain/kotlin/io/github/timortel/kmpgrpc/core/message/Message.kt

@@ -11,6 +11,8 @@ actual interface Message {
 
     actual val requiredSize: Int
 
+    actual val isInitialized: Boolean
+
     actual fun serialize(): ByteArray {
         val buffer = Buffer()
         serialize(CodedOutputStreamImpl(buffer))

kmp-grpc-internal-test/build.gradle.kts

@@ -114,11 +114,16 @@ kmpGrpc {
 
     includeWellKnownTypes = true
 
-    protoSourceFolders = project.files("src/commonMain/proto/general", "src/commonMain/proto/unknownfield", "src/commonMain/proto/editions")
+    protoSourceFolders = project.files(
+        "src/commonMain/proto/general",
+        "src/commonMain/proto/unknownfield",
+        "src/commonMain/proto/editions",
+        "src/commonMain/proto/proto2"
+    )
 }
 
 buildConfig {
-    packageName("iio.github.timortel.kmpgrpc.internal.test")
+    packageName("io.github.timortel.kmpgrpc.internal.test")
 
     useKotlinOutput {
         internalVisibility = true

kmp-grpc-internal-test/src/commonMain/proto/proto2/proto2-group-test.proto

@@ -0,0 +1,43 @@
+syntax = "proto2";
+
+package io.github.timortel.kmpgrpc.test.proto2;
+
+option java_outer_classname = "Proto2GroupTest";
+
+message A {
+  optional group B = 1 {
+    optional string field1 = 1;
+    optional int32 field2 = 2;
+
+    optional group C = 3 {
+      optional string field1 = 1;
+
+      optional string field2 = 2;
+    }
+  }
+
+  repeated group D = 2 {
+    optional string field1 = 1;
+    optional int32 field2 = 2;
+  }
+}
+
+message E {
+  optional string field1 = 1;
+  optional group G = 2 {
+    optional string field1 = 1;
+    extensions 2 to max;
+  }
+
+  extensions 3 to max;
+}
+
+extend E {
+  optional group F = 4 {
+    optional string field1 = 1;
+  }
+}
+
+extend E.G {
+  optional string field2 = 2;
+}

kmp-grpc-internal-test/src/commonMain/proto/proto2/proto2-required-fields.proto

@@ -0,0 +1,22 @@
+syntax = "proto2";
+
+package io.github.timortel.kmpgrpc.test.proto2;
+
+option java_outer_classname = "Proto2RequiredFields";
+
+message Proto2MessageWithMixedFields {
+  required string field1 = 1;
+  optional int32 field2 = 2;
+}
+
+message Proto2MessageWithRequiredFields {
+  required string field1 = 1;
+  required Proto2MessageWithMixedFields field2 = 2;
+  repeated Proto2MessageWithRequiredFields field3 = 3;
+  map<string, Proto2MessageWithRequiredFields> field4 = 4;
+
+  oneof x {
+      Proto2MessageWithMixedFields field5 = 5;
+      string field6 = 6;
+  }
+}

kmp-grpc-internal-test/src/commonMain/proto/proto2/proto2-test-service.proto

@@ -0,0 +1,11 @@
+syntax = "proto2";
+
+package io.github.timortel.kmpgrpc.test.proto2;
+
+import "proto2-group-test.proto";
+
+option java_multiple_files = true;
+
+service Proto2TestService {
+  rpc sendMessageWithNestedGroups (A) returns (A);
+}

kmp-grpc-internal-test/src/commonTest/kotlin/io/github/timortel/kotlin_multiplatform_grpc_plugin/test/defaults.kt

@@ -3,6 +3,7 @@ package io.github.timortel.kotlin_multiplatform_grpc_plugin.test
 import ExtensionsTest
 import io.github.timortel.kmpgrpc.core.message.extensions.buildExtensions
 import io.github.timortel.kmpgrpc.test.*
+import io.github.timortel.kmpgrpc.test.proto2.Proto2GroupTest
 
 fun createScalarMessage() = scalarTypes {
     field1 = "Test"
@@ -102,11 +103,13 @@ fun createMessageWithAllExtensions() = ExtensionsTest.MessageWithEveryExtension(
         set(ExtensionsTest.field33, listOf(0uL, 134uL, 353111345134uL))
         set(ExtensionsTest.field34, listOf(-14, 0, 1241522))
         set(ExtensionsTest.field35, listOf(-154L, 0L, 4514124121L))
-        set(ExtensionsTest.field36, listOf(
-            byteArrayOf(0, -127, 127),
-            byteArrayOf(-123, 1, 2),
-            byteArrayOf(3, 3, -6)
-        ))
+        set(
+            ExtensionsTest.field36, listOf(
+                byteArrayOf(0, -127, 127),
+                byteArrayOf(-123, 1, 2),
+                byteArrayOf(3, 3, -6)
+            )
+        )
     }
 )
 
@@ -188,3 +191,32 @@ fun createEditionsNonPackedTypesMessage(): EditionsNonPackedTypesMessage = Editi
     field12List = field12,
     field13List = field13,
 )
+
+fun createProto2NestedGroupMessage() = Proto2GroupTest.A(
+    b = Proto2GroupTest.A.B(
+        field1 = "text1",
+        field2 = 2,
+        c = Proto2GroupTest.A.B.C(field1 = "text3", field2 = "text4")
+    ),
+    dList = listOf(
+        Proto2GroupTest.A.D(field1 = "text5", field2 = 6),
+        Proto2GroupTest.A.D(field1 = "text7", field2 = 8)
+    )
+)
+
+fun createProto2GroupMessageWithExtensions() = Proto2GroupTest.E(
+    field1 = "text1",
+    g = Proto2GroupTest.E.G(
+        field1 = "text2",
+        extensions = buildExtensions {
+            set(Proto2GroupTest.field2, "text3")
+        }
+    ),
+    extensions = buildExtensions {
+        set(
+            Proto2GroupTest.f, Proto2GroupTest.F(
+                field1 = "text4"
+            )
+        )
+    }
+)

kmp-grpc-internal-test/src/commonTest/kotlin/io/github/timortel/kotlin_multiplatform_grpc_plugin/test/integration/EditionsRpcTest.kt

@@ -1,6 +1,8 @@
 package io.github.timortel.kotlin_multiplatform_grpc_plugin.test.integration
 
 import io.github.timortel.kmpgrpc.core.Channel
+import io.github.timortel.kmpgrpc.core.Code
+import io.github.timortel.kmpgrpc.core.StatusException
 import io.github.timortel.kmpgrpc.test.EditionsTestServiceStub
 import io.github.timortel.kmpgrpc.test.editions.EditionsLegacyField
 import io.github.timortel.kotlin_multiplatform_grpc_plugin.test.createEditionsNonPackedTypesMessage
@@ -9,6 +11,7 @@ import io.github.timortel.kotlin_multiplatform_grpc_plugin.test.createMessageWit
 import kotlinx.coroutines.test.runTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
 
 abstract class EditionsRpcTest : ServerTest {
 
@@ -39,9 +42,11 @@ abstract class EditionsRpcTest : ServerTest {
     @Test
     fun testLegacyRequiredFieldNoData() = runTest {
         val message = EditionsLegacyField()
-        val response = stub.sendLegacyRequiredField(message)
+        val exception = assertFailsWith<StatusException> {
+            stub.sendLegacyRequiredField(message)
+        }
 
-        assertEquals(message, response)
+        assertEquals(Code.INTERNAL, exception.status.code)
     }
 
     @Test

kmp-grpc-internal-test/src/commonTest/kotlin/io/github/timortel/kotlin_multiplatform_grpc_plugin/test/integration/RpcTest.kt

@@ -5,7 +5,9 @@ import io.github.timortel.kmpgrpc.core.Code
 import io.github.timortel.kmpgrpc.core.StatusException
 import io.github.timortel.kmpgrpc.core.message.UnknownField
 import io.github.timortel.kmpgrpc.test.*
+import io.github.timortel.kmpgrpc.test.proto2.Proto2TestServiceStub
 import io.github.timortel.kotlin_multiplatform_grpc_plugin.test.createMessageWithAllTypes
+import io.github.timortel.kotlin_multiplatform_grpc_plugin.test.createProto2NestedGroupMessage
 import io.github.timortel.kotlin_multiplatform_grpc_plugin.test.createScalarMessage
 import kotlinx.coroutines.*
 import kotlinx.coroutines.flow.Flow
@@ -141,6 +143,15 @@ abstract class RpcTest : ServerTest {
         assertEquals(baseMessage, returnedMessage)
     }
 
+    @Test
+    fun testSendNestedGroupMessage() = runTest {
+        val message = createProto2NestedGroupMessage()
+
+        val stub = Proto2TestServiceStub(channel)
+        val returnedMessage = stub.sendMessageWithNestedGroups(message)
+        assertEquals(message, returnedMessage)
+    }
+
     @Test
     fun testFailedRpcThrowsKmStatusException() = runTest {
         val message = simpleMessage { }