ScalaPB，proto3:将字段设置为None，没有可用的optionalX前缀

Question

在Person和Address消息定义中使用https://scalapb.github.io/generated-code.html

syntax = "proto3";
package trexo.scalapb;

message Person {
  string name = 1;
  int32 age = 2;

  repeated Address addresses = 3;
}

message Address {
  string street = 1;
  string city = 2;
}

生成设置为：

// project/plugins.sbt
addSbtPlugin("com.thesamet" % "sbt-protoc" % "0.99.28")
libraryDependencies += "com.thesamet.scalapb" %% "compilerplugin" % "0.10.1"

// build.sbt
name         := "ProtobufPlayAround"
version      := "0.1"
scalaVersion := "2.12.10"

PB.targets in Compile := Seq(
  scalapb.gen() -> (sourceManaged in Compile).value
)

val scalapbVersion = scalapb.compiler.Version.scalapbVersion

libraryDependencies ++= Seq(
  "org.scalatest" %% "scalatest" % "3.1.1" % "test",
  "com.thesamet.scalapb" %% "scalapb-runtime" % scalapbVersion  % "protobuf"
)

然后我创建了一个测试：

import org.scalatest.freespec.AnyFreeSpec
import org.scalatest.matchers.should.Matchers
import trexo.scalapb.myprotos.{Address, Person}

class SerializeSpec extends AnyFreeSpec with Matchers {
  "TEST #1 .update() with concrete value (no Option)" in {
    val street1 = "Mount Everest"
    val city1   = "Himālaya"

    val expectedAddr = Address(street1, city1)

    val updAddr = Address().update(
      _.street := street1,
      _.city   := city1
    )
    updAddr shouldEqual expectedAddr
  }

  "TEST #2 .update() with Option value" in {
    val bogusAddr = Address(street = "Huh?", city = "Ah?")

    val emptyAddr = bogusAddr.update(
      _.optionalStreet := None,
      _.optionalCity   := None
    )

    emptyAddr shouldEqual Address()
  }
}

测试1通过。测试2编译失败

错误：(98，40)值optionalStreet不是optionalStreet trexo.scalapb.myprotos.Address val emptyAddr = bogusAddr.update(_.optionalStreet := None)的成员

reproduced：在ScalaPB文档中，据说有一种方法可以更新可选字段(为了方便起见，在下面转载)。更新的_.optionalX方式是否更改为不同的语法？

val p = Person().update(
  // Pass the value directly:
  _.name := "John",

  // Use the optionalX prefix and pass an Option:
  _.optionalAge := Some(37)  // ...or None
)

Answer 1

在您的实现中，您没有可选字段。如果您希望有一个可选字段，则需要编写如下代码：

syntax = "proto3";
package trexo.scalapb;
import "google/protobuf/wrappers.proto";

message Person {
  string name = 1;
  google.protobuf.Int32Value age = 2;

  repeated Address addresses = 3;
}

message Address {
  string street = 1;
  string city = 2;
}

请参见实例中的字段年龄，现在它将是可选的。