Support most of edition 2023 presence semantics (#326)

protokt-codegen/src/main/kotlin/protokt/v1/codegen/util/FieldParser.kt

@@ -19,6 +19,8 @@ import com.google.common.base.CaseFormat.LOWER_CAMEL
 import com.google.common.base.CaseFormat.LOWER_UNDERSCORE
 import com.google.common.base.CaseFormat.UPPER_CAMEL
 import com.google.protobuf.DescriptorProtos.DescriptorProto
+import com.google.protobuf.DescriptorProtos.FeatureSet
+import com.google.protobuf.DescriptorProtos.FeatureSet.FieldPresence
 import com.google.protobuf.DescriptorProtos.FieldDescriptorProto
 import com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Label.LABEL_OPTIONAL
 import com.google.protobuf.DescriptorProtos.FieldDescriptorProto.Label.LABEL_REPEATED
@@ -207,7 +209,19 @@ internal class FieldParser(
     }
 
     private fun optional(fdp: FieldDescriptorProto) =
-        (fdp.label == LABEL_OPTIONAL && ctx.proto2) || fdp.proto3Optional
+        when {
+            ctx.proto2 -> fdp.label == LABEL_OPTIONAL
+            ctx.proto3 -> fdp.proto3Optional
+            ctx.edition2023 -> optional(ctx.fileOptions.default.features, fdp.options.features)
+            else -> error("unexpected edition/syntax")
+        }
+
+    private fun optional(fileFeatures: FeatureSet, fieldFeatures: FeatureSet) =
+        if (fileFeatures.fieldPresence == FieldPresence.EXPLICIT) {
+            fieldFeatures.fieldPresence !in setOf(FieldPresence.IMPLICIT, FieldPresence.LEGACY_REQUIRED)
+        } else {
+            fieldFeatures.fieldPresence == FieldPresence.EXPLICIT
+        }
 
     private fun packed(type: FieldType, fdp: FieldDescriptorProto) =
         type.packable &&

protokt-codegen/src/main/kotlin/protokt/v1/codegen/util/GeneratorContext.kt

@@ -15,6 +15,7 @@
 
 package protokt.v1.codegen.util
 
+import com.google.protobuf.DescriptorProtos
 import com.google.protobuf.DescriptorProtos.FileDescriptorProto
 import com.toasttab.protokt.v1.ProtoktProtos
 import protokt.v1.gradle.PROTOKT_VERSION
@@ -44,6 +45,7 @@ internal class GeneratorContext(
 
     val proto2 = !fdp.hasSyntax() || fdp.syntax == "proto2"
     val proto3 = fdp.syntax == "proto3"
+    val edition2023 = fdp.edition == DescriptorProtos.Edition.EDITION_2023
 }
 
 val FileDescriptorProto.fileOptions

testing/protokt-generation/src/main/proto/protokt/v1/testing/edition_2023_presence_file_explicit.proto

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2024 Toast, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+edition = "2023";
+
+package protokt.v1.testing;
+
+option features.field_presence = EXPLICIT;
+
+import "google/protobuf/empty.proto";
+
+message TestFileExplicit {
+  int32 foo = 1;
+  google.protobuf.Empty bar = 2;
+
+  int32 baz = 3 [features.field_presence = EXPLICIT];
+  google.protobuf.Empty qux = 4 [features.field_presence = EXPLICIT];
+
+  int32 corge = 5 [features.field_presence = IMPLICIT];
+  // not allowed: google.protobuf.Empty grault = 6 [features.field_presence = IMPLICIT];
+
+  int32 garply = 7 [features.field_presence = LEGACY_REQUIRED];
+  google.protobuf.Empty thud = 8 [features.field_presence = LEGACY_REQUIRED];
+}

testing/protokt-generation/src/main/proto/protokt/v1/testing/edition_2023_presence_file_implicit.proto

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2024 Toast, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+edition = "2023";
+
+package protokt.v1.testing;
+
+option features.field_presence = IMPLICIT;
+
+import "google/protobuf/empty.proto";
+
+message TestFileImplicit {
+  int32 foo = 1;
+  google.protobuf.Empty bar = 2;
+
+  int32 baz = 3 [features.field_presence = EXPLICIT];
+  google.protobuf.Empty qux = 4 [features.field_presence = EXPLICIT];
+
+  int32 corge = 5 [features.field_presence = IMPLICIT];
+  // not allowed: google.protobuf.Empty grault = 6 [features.field_presence = IMPLICIT];
+
+  int32 garply = 7 [features.field_presence = LEGACY_REQUIRED];
+  google.protobuf.Empty thud = 8 [features.field_presence = LEGACY_REQUIRED];
+}

testing/protokt-generation/src/main/proto/protokt/v1/testing/edition_2023_presence_file_legacy_required.proto

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2024 Toast, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+edition = "2023";
+
+package protokt.v1.testing;
+
+// not allowed: option features.field_presence = LEGACY_REQUIRED;

testing/protokt-generation/src/test/kotlin/protokt/v1/testing/Edition2023PresenceTest.kt

@@ -0,0 +1,104 @@
+/*
+ * Copyright (c) 2024 Toast, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package protokt.v1.testing
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class Edition2023PresenceTest {
+    @Test
+    fun `file with implicit presence and no field features has correct behavior on primitive`() {
+        assertThat(TestFileImplicit::class.propertyIsMarkedNullable("foo")).isFalse()
+        assertThat(TestFileImplicit {}.foo).isEqualTo(0)
+
+        assertThat(TestFileImplicit::class.propertyIsMarkedNullable("corge")).isFalse()
+        assertThat(TestFileImplicit {}.corge).isEqualTo(0)
+    }
+
+    @Test
+    fun `file with implicit presence and no field features has correct behavior on message`() {
+        assertThat(TestFileImplicit::class.propertyIsMarkedNullable("bar")).isTrue()
+        assertThat(TestFileImplicit {}.bar).isNull()
+    }
+
+    @Test
+    fun `file with implicit presence and field with explicit presence has correct behavior on primitive`() {
+        assertThat(TestFileImplicit::class.propertyIsMarkedNullable("baz")).isTrue()
+        assertThat(TestFileImplicit {}.baz).isNull()
+    }
+
+    @Test
+    fun `file with implicit presence and field with explicit presence has correct behavior on message`() {
+        assertThat(TestFileImplicit::class.propertyIsMarkedNullable("qux")).isTrue()
+        assertThat(TestFileImplicit {}.qux).isNull()
+    }
+
+    @Test
+    fun `file with implicit presence and field with legacy required presence has correct behavior on primitive`() {
+        assertThat(TestFileImplicit::class.propertyIsMarkedNullable("garply")).isFalse()
+        assertThat(TestFileImplicit {}.garply).isEqualTo(0)
+    }
+
+    @Test
+    fun `file with implicit presence and field with legacy required for message type`() {
+        // protokt doesn't support non-null message types
+        assertThat(TestFileImplicit::class.propertyIsMarkedNullable("thud")).isTrue()
+        assertThat(TestFileImplicit {}.thud).isNull()
+    }
+
+    @Test
+    fun `file with explicit presence and no field features has correct behavior on primitive`() {
+        assertThat(TestFileImplicit::class.propertyIsMarkedNullable("foo")).isFalse()
+        assertThat(TestFileImplicit {}.foo).isEqualTo(0)
+    }
+
+    @Test
+    fun `file with explicit presence and no field features has correct behavior on message`() {
+        assertThat(TestFileImplicit::class.propertyIsMarkedNullable("bar")).isTrue()
+        assertThat(TestFileImplicit {}.bar).isNull()
+    }
+
+    @Test
+    fun `file with explicit presence and field with explicit presence has correct behavior on primitive`() {
+        assertThat(TestFileImplicit::class.propertyIsMarkedNullable("baz")).isTrue()
+        assertThat(TestFileImplicit {}.baz).isNull()
+    }
+
+    @Test
+    fun `file with explicit presence and field with explicit presence has correct behavior on message`() {
+        assertThat(TestFileImplicit::class.propertyIsMarkedNullable("qux")).isTrue()
+        assertThat(TestFileImplicit {}.qux).isNull()
+    }
+
+    @Test
+    fun `file with explicit presence and field with implicit presence has correct behavior on primitive`() {
+        assertThat(TestFileImplicit::class.propertyIsMarkedNullable("corge")).isFalse()
+        assertThat(TestFileImplicit {}.corge).isEqualTo(0)
+    }
+
+    @Test
+    fun `file with explicit presence and field with legacy required presence has correct behavior on primitive`() {
+        assertThat(TestFileImplicit::class.propertyIsMarkedNullable("garply")).isFalse()
+        assertThat(TestFileImplicit {}.garply).isEqualTo(0)
+    }
+
+    @Test
+    fun `file with explicit presence and field with legacy required for message type`() {
+        // protokt doesn't support non-null message types
+        assertThat(TestFileImplicit::class.propertyIsMarkedNullable("thud")).isTrue()
+        assertThat(TestFileImplicit {}.thud).isNull()
+    }
+}