scala - shapeless.~?>.witness[Nothing, Nothing, T](shapeless.~?>.rel[Nothing, Nothing]) 将scala版本从2升级到3

Question

我正在将我的 scala 项目从版本 2 升级到 3。

这是我的 build.sbt 版本 scala 版本 2

    scalaVersion := "2.13.5"
    version := "1.0.0"
    libraryDependencies += "com.chuusai" %% "shapeless" % "2.3.7"
    libraryDependencies += "org.scodec" %% "scodec-core" % "1.11.4"
    libraryDependencies += "org.slf4j" % "slf4j-log4j12" % "1.7.31"

以下是示例 scala 代码 -

    import scodec._
    import scodec.codecs._
    import scodec.bits._
    import scodec.codecs.implicits._
    import org.slf4j.LoggerFactory


    object AkkaEventSerializer {

      def toBinary(o: AnyRef): Array[Byte] =  o match {
        case e: Event => Codec.encode(e).require.toByteArray
        case x => throw new Exception(s"unexpected  object $x received which is ${x.getClass} type")
      }

      def fromBinary(bytes: Array[Byte], manifest: String): AnyRef = manifest match {
        case EventManifest => Codec[Event].decode(BitVector.apply(bytes)).require.value
        case x => throw new Exception(s"unexpected manifest $x in AdServerAkkaEventSerializer.fromBinary ")
      }

      final val EventManifest = classOf[Event].getName

      val  logger = LoggerFactory.getLogger(AkkaEventSerializer.getClass)

      case class Event(etype: Int, cp: Option[Double], userId: Option[String], buyerId: Option[String] = None)

    }

这适用于 scala 版本 2。

现在我将 scala 版本升级到 3。

下面是 build.sbt -

    scalaVersion := "3.0.0"
    version := "1.0.0"
    crossScalaVersions := Seq("2.13.5", "3.0.0")
    libraryDependencies += ("com.chuusai" %% "shapeless" % "2.3.7").cross(CrossVersion.for3Use2_13)
    libraryDependencies += ("org.scodec" %% "scodec-core" % "1.11.4").cross(CrossVersion.for3Use2_13)
    libraryDependencies += "org.slf4j" % "slf4j-log4j12" % "1.7.31"

下面是代码 scala 版本 3 -

    import scodec._
    import scodec.codecs._
    import scodec.bits._
    import scodec.codecs.implicits._
    import org.slf4j.LoggerFactory
    import shapeless.~?>.idKeyWitness
    import shapeless.~?>.idValueWitness
    import shapeless.~?>.witness


    object AkkaEventSerializer {

      def toBinary(o: AnyRef): Array[Byte] =  o match {
        case e: Event => Codec.encode(e).require.toByteArray
        case x => throw new Exception(s"unexpected  object $x received which is ${x.getClass} type")
      }

      def fromBinary(bytes: Array[Byte], manifest: String): AnyRef = manifest match {
        case EventManifest => Codec[Event].decode(BitVector.apply(bytes)).require.value
        case x => throw new Exception(s"unexpected manifest $x in AdServerAkkaEventSerializer.fromBinary ")
      }

      final val EventManifest = classOf[Event].getName

      val  logger = LoggerFactory.getLogger(AkkaEventSerializer.getClass)

      case class Event(etype: Int, cp: Option[Double], userId: Option[String], buyerId: Option[String] = None)

    }

当我编译这个程序时，我得到以下错误 -

[错误] -- 错误：/Users/rajkumar.natarajan/Documents/Coding/OS/scala3-maven-build-demo/src/main/scala/com/serialize/AkkaEventSerializer.scala:17:36 [错误] 17 | 案例 e：事件 => Codec.encode(e).require.toByteArray [错误] | ^ [错误] |找不到 scodec.Codec[com.serialize.AkkaEventSerializer.Event] 类型的惰性隐式值。[错误] |我发现：[错误] | [错误] | shapeless.~?>.witness[Nothing, Nothing, T](shapeless.~?>.rel[Nothing, Nothing]) [错误] |

[错误] |但是特征 NatTRel0 中的方法见证与 shapeless.Lazy[scodec.Codec[com.serialize.AkkaEventSerializer.Event]] 类型不匹配。[错误] -- 错误：/Users/rajkumar.natarajan/Documents/Coding/OS/scala3-maven-build-demo/src/main/scala/com/serialize/AkkaEventSerializer.scala:22:38 [错误] 22 | case EventManifest => Codec[Event].decode(BitVector.apply(bytes)).require.value [error] | ^ [错误] |找不到 scodec.Codec[com.serialize.AkkaEventSerializer.Event] 类型的惰性隐式值。[错误] |我发现：

[错误] |

[错误] | shapeless.~?>.witness[Nothing, Nothing, T](shapeless.~?>.rel[Nothing, Nothing]) [错误] |

[错误] |但是特征 NatTRel0 中的方法见证与 shapeless.Lazy[scodec.Codec[com.serialize.AkkaEventSerializer.Event]] 类型不匹配。[error] 发现两个错误 [error] 发现两个错误 [error] (Compile / compileIncremental) 编译失败

我知道我们可以使用 scala 3 版本编译 scala 2.13 代码。但我不能为这段代码。

我该如何解决这个错误？

标签： scalashapelessscala-3scodec