Generator for .proto files based on serializable Kotlin classes

formats/protobuf/api/kotlinx-serialization-protobuf.api

@@ -47,3 +47,8 @@ public final class kotlinx/serialization/protobuf/ProtoType$Impl : kotlinx/seria
 	public final synthetic fun type ()Lkotlinx/serialization/protobuf/ProtoIntegerType;
 }
 
+public final class kotlinx/serialization/protobuf/schema/GenerationKt {
+	public static final fun generateProto2Schema (Ljava/util/List;Ljava/lang/String;Ljava/util/Map;)Ljava/lang/String;
+	public static synthetic fun generateProto2Schema$default (Ljava/util/List;Ljava/lang/String;Ljava/util/Map;ILjava/lang/Object;)Ljava/lang/String;
+}
+

formats/protobuf/build.gradle

@@ -40,7 +40,7 @@ kotlin {
 }
 
 sourceSets.test.proto {
-    srcDirs = ['testProto']
+    srcDirs = ['testProto', 'jvmTest/resources/common']
 }
 
 compileTestKotlinJvm {

formats/protobuf/commonTest/src/kotlinx/serialization/protobuf/schema/SchemaValidationsTest.kt

@@ -0,0 +1,104 @@
+package kotlinx.serialization.protobuf.schema
+
+import kotlinx.serialization.*
+import kotlinx.serialization.protobuf.ProtoNumber
+import kotlin.test.Test
+import kotlin.test.assertFailsWith
+
+class SchemaValidationsTest {
+    @Serializable
+    data class ValidClass(val i: Int)
+
+    @Serializable
+    @SerialName("ValidClass")
+    data class DuplicateClass(val l: Long)
+
+    @Serializable
+    @SerialName("invalid serial name")
+    data class InvalidClassName(val i: Int)
+
+    @Serializable
+    data class InvalidClassFieldName(@SerialName("invalid serial name") val i: Int)
+
+    @Serializable
+    data class FieldNumberDuplicates(@ProtoNumber(42) val i: Int, @ProtoNumber(42) val j: Int)
+
+    @Serializable
+    data class FieldNumberImplicitlyDuplicates(@ProtoNumber(2) val i: Int, val j: Int)
+
+    @Serializable
+    @SerialName("invalid serial name")
+    enum class InvalidEnumName { SINGLETON }
+
+    @Serializable
+    enum class InvalidEnumElementName {
+        FIRST,
+
+        @SerialName("invalid serial name")
+        SECOND
+    }
+
+
+    @Test
+    fun testInvalidEnumElementSerialName() {
+        val descriptors = listOf(InvalidEnumElementName.serializer().descriptor)
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(descriptors) }
+    }
+
+    @Test
+    fun testInvalidClassSerialName() {
+        val descriptors = listOf(InvalidClassName.serializer().descriptor)
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(descriptors) }
+    }
+
+    @Test
+    fun testInvalidClassFieldSerialName() {
+        val descriptors = listOf(InvalidClassFieldName.serializer().descriptor)
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(descriptors) }
+    }
+
+    @Test
+    fun testDuplicateSerialNames() {
+        val descriptors = listOf(InvalidClassFieldName.serializer().descriptor)
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(descriptors) }
+    }
+
+    @Test
+    fun testInvalidEnumSerialName() {
+        val descriptors = listOf(InvalidEnumName.serializer().descriptor)
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(descriptors) }
+    }
+
+    @Test
+    fun testDuplicationSerialName() {
+        val descriptors = listOf(ValidClass.serializer().descriptor, DuplicateClass.serializer().descriptor)
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(descriptors) }
+    }
+
+    @Test
+    fun testIllegalPackageNames() {
+        val descriptors = listOf(ValidClass.serializer().descriptor)
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(descriptors, "") }
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(descriptors, ".") }
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(descriptors, ".first.dot") }
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(descriptors, "ended.with.dot.") }
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(descriptors, "first._underscore") }
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(descriptors, "first.1digit") }
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(descriptors, "illegal.sym+bol") }
+    }
+
+    @Test
+    fun testValidPackageNames() {
+        val descriptors = listOf(ValidClass.serializer().descriptor)
+        generateProto2Schema(descriptors, "singleIdent")
+        generateProto2Schema(descriptors, "double.ident")
+        generateProto2Schema(descriptors, "with.digits0123")
+        generateProto2Schema(descriptors, "with.underscore_")
+    }
+
+    @Test
+    fun testFieldNumberDuplicates() {
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(listOf(FieldNumberDuplicates.serializer().descriptor)) }
+        assertFailsWith(IllegalArgumentException::class) { generateProto2Schema(listOf(FieldNumberImplicitlyDuplicates.serializer().descriptor)) }
+    }
+}

formats/protobuf/jvmTest/resources/AbstractHolder.proto

@@ -0,0 +1,14 @@
+syntax = "proto2";
+
+package kotlinx.serialization.protobuf.schema.generator;
+
+// serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.AbstractHolder'
+message AbstractHolder {
+  required KotlinxSerializationPolymorphic abs = 1;
+}
+
+// serial name 'KotlinxSerializationPolymorphic'
+message KotlinxSerializationPolymorphic {
+  required string type = 1;
+  required bytes value = 2;
+}

formats/protobuf/jvmTest/resources/ContextualHolder.proto

@@ -0,0 +1,8 @@
+syntax = "proto2";
+
+package kotlinx.serialization.protobuf.schema.generator;
+
+// serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.ContextualHolder'
+message ContextualHolder {
+  required bytes value = 1;
+}

formats/protobuf/jvmTest/resources/FieldNumberClass.proto

@@ -0,0 +1,10 @@
+syntax = "proto2";
+
+package kotlinx.serialization.protobuf.schema.generator;
+
+// serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.FieldNumberClass'
+message FieldNumberClass {
+  required int32 a = 1;
+  required int32 b = 5;
+  required int32 c = 3;
+}

formats/protobuf/jvmTest/resources/LegacyMapHolder.proto

@@ -0,0 +1,59 @@
+syntax = "proto2";
+
+package kotlinx.serialization.protobuf.schema.generator;
+
+// serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.LegacyMapHolder'
+message LegacyMapHolder {
+  repeated LegacyMapHolder_keyAsMessage keyAsMessage = 1;
+  repeated LegacyMapHolder_keyAsEnum keyAsEnum = 2;
+  repeated LegacyMapHolder_keyAsBytes keyAsBytes = 3;
+  repeated LegacyMapHolder_keyAsList keyAsList = 4;
+  repeated LegacyMapHolder_keyAsDeepList keyAsDeepList = 5;
+}
+
+// serial name 'LegacyMapHolder_keyAsMessage'
+message LegacyMapHolder_keyAsMessage {
+  required OptionsClass key = 1;
+  required int32 value = 2;
+}
+
+// serial name 'LegacyMapHolder_keyAsEnum'
+message LegacyMapHolder_keyAsEnum {
+  required OverriddenEnumName key = 1;
+  required OptionsClass value = 2;
+}
+
+// serial name 'LegacyMapHolder_keyAsBytes'
+message LegacyMapHolder_keyAsBytes {
+  required bytes key = 1;
+  required bytes value = 2;
+}
+
+// serial name 'LegacyMapHolder_keyAsList'
+message LegacyMapHolder_keyAsList {
+  repeated int32 key = 1;
+  required bytes value = 2;
+}
+
+// serial name 'LegacyMapHolder_keyAsDeepList'
+message LegacyMapHolder_keyAsDeepList {
+  repeated LegacyMapHolder_keyAsDeepList_key key = 1;
+  required bytes value = 2;
+}
+
+// serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.OptionsClass'
+message OptionsClass {
+  required int32 i = 1;
+}
+
+// serial name 'OverriddenEnumName'
+enum OverriddenEnumName {
+  FIRST = 0;
+  OverriddenElementName = 1;
+}
+
+
+// serial name 'LegacyMapHolder_keyAsDeepList_key'
+message LegacyMapHolder_keyAsDeepList_key {
+  repeated int32 value = 1;
+}

formats/protobuf/jvmTest/resources/ListClass.proto

@@ -0,0 +1,24 @@
+syntax = "proto2";
+
+package kotlinx.serialization.protobuf.schema.generator;
+
+// serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.ListClass'
+message ListClass {
+  repeated int32 intList = 1;
+  repeated int32 intArray = 2;
+  // WARNING: null value is not supported for list elements
+  repeated int32 boxedIntArray = 3;
+  repeated OptionsClass messageList = 4;
+  repeated OverriddenEnumName enumList = 5;
+}
+
+// serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.OptionsClass'
+message OptionsClass {
+  required int32 i = 1;
+}
+
+// serial name 'OverriddenEnumName'
+enum OverriddenEnumName {
+  FIRST = 0;
+  OverriddenElementName = 1;
+}

formats/protobuf/jvmTest/resources/MapClass.proto

@@ -0,0 +1,22 @@
+syntax = "proto2";
+
+package kotlinx.serialization.protobuf.schema.generator;
+
+// serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.MapClass'
+message MapClass {
+  map<int32, float> scalarMap = 1;
+  map<int32, bytes> bytesMap = 2;
+  map<string, OptionsClass> messageMap = 3;
+  map<bool, OverriddenEnumName> enumMap = 4;
+}
+
+// serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.OptionsClass'
+message OptionsClass {
+  required int32 i = 1;
+}
+
+// serial name 'OverriddenEnumName'
+enum OverriddenEnumName {
+  FIRST = 0;
+  OverriddenElementName = 1;
+}

formats/protobuf/jvmTest/resources/NestedCollections.proto

@@ -0,0 +1,37 @@
+syntax = "proto2";
+
+package kotlinx.serialization.protobuf.schema.generator;
+
+// serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.NestedCollections'
+message NestedCollections {
+  repeated NestedCollections_intList intList = 1;
+  repeated NestedCollections_messageList messageList = 2;
+  repeated NestedCollections_mapInList mapInList = 3;
+  map<string, NestedCollections_listInMap> listInMap = 4;
+}
+
+// serial name 'NestedCollections_intList'
+message NestedCollections_intList {
+  repeated int32 value = 1;
+}
+
+// serial name 'NestedCollections_messageList'
+message NestedCollections_messageList {
+  repeated OptionsClass value = 1;
+}
+
+// serial name 'NestedCollections_mapInList'
+message NestedCollections_mapInList {
+  map<string, OptionsClass> value = 1;
+}
+
+// serial name 'NestedCollections_listInMap'
+message NestedCollections_listInMap {
+  repeated int32 value = 1;
+}
+
+// serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.OptionsClass'
+message OptionsClass {
+  required int32 i = 1;
+}
+

formats/protobuf/jvmTest/resources/NullableNestedCollections.proto

@@ -0,0 +1,46 @@
+syntax = "proto2";
+
+package kotlinx.serialization.protobuf.schema.generator;
+
+// serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.NullableNestedCollections'
+message NullableNestedCollections {
+  // WARNING: null value is not supported for nested collections
+  repeated NullableNestedCollections_nullableIntList nullableIntList = 1;
+  // WARNING: null value is not supported for nested collections
+  map<string, NullableNestedCollections_nullableIntMap> nullableIntMap = 2;
+  map<string, NullableNestedCollections_intMap> intMap = 3;
+  repeated NullableNestedCollections_intList intList = 4;
+  repeated NullableNestedCollections_legacyMap legacyMap = 5;
+}
+
+// serial name 'NullableNestedCollections_nullableIntList'
+message NullableNestedCollections_nullableIntList {
+  // WARNING: This field is marked as nullable but it does not support null values
+  repeated int32 value = 1;
+}
+
+// serial name 'NullableNestedCollections_nullableIntMap'
+message NullableNestedCollections_nullableIntMap {
+  // WARNING: This field is marked as nullable but it does not support null values
+  repeated int32 value = 1;
+}
+
+// serial name 'NullableNestedCollections_intMap'
+message NullableNestedCollections_intMap {
+  // WARNING: null value is not supported for list elements
+  repeated int32 value = 1;
+}
+
+// serial name 'NullableNestedCollections_intList'
+message NullableNestedCollections_intList {
+  // WARNING: null value is not supported for list elements
+  repeated int32 value = 1;
+}
+
+// serial name 'NullableNestedCollections_legacyMap'
+message NullableNestedCollections_legacyMap {
+  // WARNING: This field is marked as nullable but it does not support null values
+  repeated int32 key = 1;
+  // WARNING: This field is marked as nullable but it does not support null values
+  repeated int32 value = 2;
+}

formats/protobuf/jvmTest/resources/OptionalClass.proto

@@ -0,0 +1,14 @@
+syntax = "proto2";
+
+package kotlinx.serialization.protobuf.schema.generator;
+
+// serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.OptionalClass'
+message OptionalClass {
+  required int32 requiredInt = 1;
+  // WARNING: an absence value is decoded as a default value that is not present in the schema
+  optional int32 optionalInt = 2;
+  optional int32 nullableInt = 3;
+  // WARNING: this field is nullable and has default value, it's impossible to unambiguously interpret an absence value.
+  //   For this field null value does not support and absence value denotes as default value. Default value is not present in the schema.
+  optional int32 nullableOptionalInt = 4;
+}

formats/protobuf/jvmTest/resources/OptionalCollections.proto

@@ -0,0 +1,25 @@
+syntax = "proto2";
+
+package kotlinx.serialization.protobuf.schema.generator;
+
+// serial name 'kotlinx.serialization.protobuf.schema.GenerationTest.OptionalCollections'
+message OptionalCollections {
+  repeated int32 requiredList = 1;
+  // WARNING: This field does not support empty list
+  //  An absence value is decoded as a default value that is not present in the schema
+  repeated int32 optionalList = 2;
+  // WARNING: This field is marked as nullable but it does not support null values
+  repeated int32 nullableList = 3;
+  // WARNING: This field is marked as nullable and has a default value but it does not support null values and empty list
+  //  An absence value is decoded as a default value that is not present in the schema
+  repeated int32 nullableOptionalList = 4;
+  map<int32, int32> requiredMap = 5;
+  // WARNING: This field does not support empty map
+  //  An absence value is decoded as a default value that is not present in the schema
+  map<int32, int32> optionalMap = 6;
+  // WARNING: This field is marked as nullable but it does not support null values
+  map<int32, int32> nullableMap = 7;
+  // WARNING: This field is marked as nullable and has a default value but it does not support null values and empty map
+  //  An absence value is decoded as a default value that is not present in the schema
+  map<int32, int32> nullableOptionalMap = 8;
+}