r - 在带有rscala的R中使用Scala时出现NoSuchMethodError

我在R中使用rscala包调用预编译的Scala代码时遇到麻烦。

我有一个运行在2.11.12版本上的Scala项目。我用sbt-assembly构建了一个 fat jar ，并通过rscala::scala("path-to-jar.jar")将其提供给rscala

但是，每当我尝试从程序包中运行任何函数/方法/任何内容时，都会收到以下错误:

java.lang.reflect.InvocationTargetException
java.lang.NoSuchMethodError: scala.Predef$.refArrayOps([Ljava/lang/Object;)Lscala/collection/mutable/ArrayOps;
    at myPackage.myClass$.myMethod(myClass.scala:116)
    at $line6.$read$$iw$$iw$$iw$$iw$.$anonfun$res0$1(<console>:16)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.ddahl.rscala.server.Server.$anonfun$invoke$3(Server.scala:305)
    at org.ddahl.rscala.server.Server.wrap(Server.scala:47)
    at org.ddahl.rscala.server.Server.invoke(Server.scala:305)
    at org.ddahl.rscala.server.Server.run(Server.scala:400)
    at org.ddahl.rscala.server.Main$.delayedEndpoint$org$ddahl$rscala$server$Main$1(Main.scala:105)
    at org.ddahl.rscala.server.Main$delayedInit$body.apply(Main.scala:11)
    at scala.Function0.apply$mcV$sp(Function0.scala:39)
    at scala.Function0.apply$mcV$sp$(Function0.scala:39)
    at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:17)
    at scala.App.$anonfun$main$1$adapted(App.scala:80)
    at scala.collection.immutable.List.foreach(List.scala:392)
    at scala.App.main(App.scala:80)
    at scala.App.main$(App.scala:78)
    at org.ddahl.rscala.server.Main$.main(Main.scala:11)
    at org.ddahl.rscala.server.Main.main(Main.scala)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at scala.reflect.internal.util.ScalaClassLoader.$anonfun$run$2(ScalaClassLoader.scala:106)
    at scala.reflect.internal.util.ScalaClassLoader.asContext(ScalaClassLoader.scala:41)
    at scala.reflect.internal.util.ScalaClassLoader.asContext$(ScalaClassLoader.scala:37)
    at scala.reflect.internal.util.ScalaClassLoader$URLClassLoader.asContext(ScalaClassLoader.scala:132)
    at scala.reflect.internal.util.ScalaClassLoader.run(ScalaClassLoader.scala:106)
    at scala.reflect.internal.util.ScalaClassLoader.run$(ScalaClassLoader.scala:98)
    at scala.reflect.internal.util.ScalaClassLoader$URLClassLoader.run(ScalaClassLoader.scala:132)
    at scala.tools.nsc.CommonRunner.run(ObjectRunner.scala:28)
    at scala.tools.nsc.CommonRunner.run$(ObjectRunner.scala:27)
    at scala.tools.nsc.ObjectRunner$.run(ObjectRunner.scala:45)
    at scala.tools.nsc.CommonRunner.runAndCatch(ObjectRunner.scala:35)
    at scala.tools.nsc.CommonRunner.runAndCatch$(ObjectRunner.scala:34)
    at scala.tools.nsc.ObjectRunner$.runAndCatch(ObjectRunner.scala:45)
    at scala.tools.nsc.MainGenericRunner.runTarget$1(MainGenericRunner.scala:73)
    at scala.tools.nsc.MainGenericRunner.run$1(MainGenericRunner.scala:92)
    at scala.tools.nsc.MainGenericRunner.process(MainGenericRunner.scala:103)
    at scala.tools.nsc.MainGenericRunner$.main(MainGenericRunner.scala:108)
    at scala.tools.nsc.MainGenericRunner.main(MainGenericRunner.scala)
Error in pop(details, transcompileInfo, envir) : Invocation error.

它的确允许我导入其类和对象，因此它似乎确实在类路径中，仅此而已。

我的build.sbt包中包含crossScalaVersions := Seq("2.11.12", "2.12.7", "2.13.0-M5")。

有什么想法吗？这似乎是scala版本错误，因为运行rscala::scalaConfig()向我显示它正在使用scalaFullVersion 2.12.8，但是我似乎无法选择scala安装，因此我无法真正期望这是问题所在。

编辑:

在Jasper-M的建议之后，我设置了环境变量RSCALA_SCALA_MAJORVERSION=2.11，并使用rscala::scalaConfig(download='scala')重新执行了配置。现在，它返回scalaMajorVersion作为2.11。

现在，当我使用rscala::scala()创建scala桥的实例时，它将返回一条消息(不是错误)，说明:

cat: /release: No such file or directory

如果我运行println()，则可以毫无问题地进行编译。但是，如果我用自己的预编译的胖JAR实例化scala桥并执行任何操作(例如println)，它将返回以下错误:

error: error while loading package, class file '$HOME/.rscala/scala/lib/scala-library.jar(scala/reflect/package.class)' is broken
(class java.lang.RuntimeException/Scala class file does not contain Scala annotation)
error: error while loading package, class file '$HOME/.rscala/scala/lib/scala-library.jar(scala/package.class)' is broken
(class java.lang.RuntimeException/Scala class file does not contain Scala annotation)
error: error while loading package, class file '$HOME/.rscala/scala/lib/scala-library.jar(scala/reflect/package.class)' is broken
(class java.lang.RuntimeException/Scala class file does not contain Scala annotation)
error: error while loading package, class file '$HOME/.rscala/scala/lib/scala-library.jar(scala/package.class)' is broken
(class java.lang.RuntimeException/Scala class file does not contain Scala annotation)
error: error while loading Predef, class file '$HOME/.rscala/scala/lib/scala-library.jar(scala/Predef.class)' is broken
(class java.lang.RuntimeException/Scala class file does not contain Scala annotation)

我真的很笨有任何想法吗？

最佳答案

这绝对是Scala版本错误。

我最好的猜测是，您必须设置环境变量RSCALA_SCALA_MAJORVERSION=2.11。例如。通过打电话

Sys.setenv(RSCALA_SCALA_MAJORVERSION = "2.11")

然后运行

rscala::scalaConfig(download = "scala")

关于r - 在带有rscala的R中使用Scala时出现NoSuchMethodError，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/55818756/