NullPointerException during icode

[maiflai]

Hi,

scoverage/gradle-scoverage#35 was raised recently in the gradle-scoverage repository, but I think it's more likely a problem in the compiler plugin.

Compiling with 2.11.5 gives a NullPointerException with no message.

Compiling with 2.10.4 gives the following:

while compiling: /Users/stu/Documents/Eclipse/kafka/core/src/main/scala/kafka/utils/ZkUtils.scala
        during phase: icode
     library version: version 2.10.4
    compiler version: version 2.10.4
  reconstructed args: -bootclasspath /Library/Java/JavaVirtualMachines/jdk1.8.0_11.jdk/Contents/Home/jre/lib/resources.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_11.jdk/Contents/Home/jre/lib/rt.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_11.jdk/Contents/Home/jre/lib/sunrsasign.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_11.jdk/Contents/Home/jre/lib/jsse.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_11.jdk/Contents/Home/jre/lib/jce.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_11.jdk/Contents/Home/jre/lib/charsets.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_11.jdk/Contents/Home/jre/lib/jfr.jar:/Library/Java/JavaVirtualMachines/jdk1.8.0_11.jdk/Contents/Home/jre/classes:/Users/stu/.gradle/caches/modules-2/files-2.1/org.scala-lang/scala-library/2.10.4/9aae4cb1802537d604e03688cab744ff47b31a7d/scala-library-2.10.4.jar -classpath /Users/stu/Documents/Eclipse/kafka/core/build/classes/scoverage:/Users/stu/Documents/Eclipse/kafka/clients/build/libs/kafka-clients-0.8.3-SNAPSHOT.jar:/Users/stu/.gradle/caches/modules-2/files-2.1/org.apache.zookeeper/zookeeper/3.4.6/1b2502e29da1ebaade2357cd1de35a855fa3755/zookeeper-3.4.6.jar:/Users/stu/.gradle/caches/modules-2/files-2.1/com.101tec/zkclient/0.3/dedcf2b53fb742adba7080ac3aed781694ba616e/zkclient-0.3.jar:/Users/stu/.gradle/caches/modules-2/files-2.1/com.yammer.metrics/metrics-core/2.2.0/f82c035cfa786d3cbec362c38c22a5f5b1bc8724/metrics-core-2.2.0.jar:/Users/stu/.gradle/caches/modules-2/files-2.1/net.sf.jopt-simple/jopt-simple/3.2/d625f12ba08083c8c16dcedd5396ec730e9e77ab/jopt-simple-3.2.jar:/Users/stu/.gradle/caches/modules-2/files-2.1/org.slf4j/slf4j-api/1.7.6/562424e36df3d2327e8e9301a76027fca17d54ea/slf4j-api-1.7.6.jar:/Users/stu/.gradle/caches/modules-2/files-2.1/org.xerial.snappy/snappy-java/1.1.1.6/e3f12835a135c0d253bee4dbbe74d37ce35d7269/snappy-java-1.1.1.6.jar:/Users/stu/.gradle/caches/modules-2/files-2.1/net.jpountz.lz4/lz4/1.2.0/cd301e9a481eae5b68c53267100aeca43b782b9f/lz4-1.2.0.jar:/Users/stu/.gradle/caches/modules-2/files-2.1/org.slf4j/slf4j-log4j12/1.6.1/b                                                                                             d245d6746cdd4e6203e976e21d597a46f115802/slf4j-log4j12-1.6.1.jar:/Users/stu/.gradle/caches/modules-2/files-2.1/log4j/log4j/1.2.16/7999a63bfccbc7c247a9aea10d83d4272bd492c6/log4j-1.2.16.jar:/Users/stu/.gradle/caches/modules-2/files-2.1/org.scoverage/gradle-scoverage/1.0-5-g9c68988/19bd553df3d6ced75d56b9912a10672af896ba9e/gradle-scoverage-1.0-5-g9c68988.jar:/Users/stu/.gradle/caches/modules-2/files-2.1/org.scoverage/scalac-scoverage-runtime_2.10/1.0.2/92a4a183161a94d80b02697228dc9198dc12e0d8/scalac-scoverage-runtime_2.10-1.0.2.jar -deprecation -Yrangepos -Xplugin:/Users/stu/.gradle/caches/modules-2/files-2.1/org.scoverage/scalac-scoverage-plugin_2.10/1.0.2/90936f85dfa01ba63f31f11544dcec2558281426/scalac-scoverage-plugin_2.10-1.0.2.jar -unchecked -P:scoverage:dataDir:/Users/stu/Documents/Eclipse/kafka/core/build/scoverage

  last tree to typer: Literal(Constant(Class))
              symbol: null
   symbol definition: null
                 tpe: Class(classOf[java.lang.Class])
       symbol owners: 
      context owners: anonymous class anonfun$getAllPartitions$1 -> package utils

== Enclosing template or block ==

Template( // val <local $anonfun>: <notype>, tree.tpe=kafka.utils.anonfun$getAllPartitions$1
  "scala.runtime.AbstractFunction1", "scala.Serializable" // parents
  ValDef(
    private
    "_"
    <tpt>
    <empty>
  )
  // 4 statements
  DefDef( // final def apply(topic: String): Seq
    <method> final <triedcooking>
    "apply"
    []
    // 1 parameter list
    ValDef( // topic: String
      <param> <triedcooking>
      "topic"
      <tpt> // tree.tpe=String
      <empty>
    )
    <tpt> // tree.tpe=Seq
    Block( // tree.tpe=Seq
      Apply( // def invoked(id: Int,dataDir: String): Unit in object Invoker, tree.tpe=Unit
        "scoverage"."Invoker"."invoked" // def invoked(id: Int,dataDir: String): Unit in object Invoker, tree.tpe=(id: Int, dataDir: String)Unit
        // 2 arguments
        25416
        "/Users/stu/Documents/Eclipse/kafka/core/build/scoverage"
      )
      Apply( // final def $asInstanceOf[T0 >: ? <: ?](): T0 in class Object, tree.tpe=Seq
        TypeApply( // final def $asInstanceOf[T0 >: ? <: ?](): T0 in class Object, tree.tpe=()Seq
          ZkUtils.this.getChildren(ZkUtils$$anonfun$getAllPartitions$1.this.zkClient$3, {
  scoverage.Invoker.invoked(25411, "/Users/stu/Documents/Eclipse/kafka/core/build/scoverage");
  ZkUtils.this.getTopicPartitionsPath(topic)
}).map({
  (new anonymous class anonfun$apply$11(ZkUtils$$anonfun$getAllPartitions$1.this): Function1)
}, {
  scoverage.Invoker.invoked(25413, "/Users/stu/Documents/Eclipse/kafka/core/build/scoverage");
  collection.this.Seq.canBuildFrom()
}).$asInstanceOf[collection.TraversableLike]().map({
  (new anonymous class anonfun$apply$12(ZkUtils$$anonfun$getAllPartitions$1.this, topic): Function1)
}, {
  scoverage.Invoker.invoked(25415, "/Users/stu/Documents/Eclipse/kafka/core/build/scoverage");
  collection.this.Seq.canBuildFrom()
})."$asInstanceOf" // final def $asInstanceOf[T0 >: ? <: ?](): T0 in class Object, tree.tpe=[T0 >: ? <: ?]()T0
          <tpt> // tree.tpe=Seq
        )
        Nil
      )
    )
  )
  DefDef( // final def apply(v1: Object): Object
    <method> final <bridge>
    "apply"
    []
    // 1 parameter list
    ValDef( // v1: Object
      <param> <triedcooking>
      "v1"
      <tpt> // tree.tpe=Object
      <empty>
    )
    <tpt> // tree.tpe=Object
    Apply( // final def apply(topic: String): Seq, tree.tpe=Seq
      ZkUtils$$anonfun$getAllPartitions$1.this."apply" // final def apply(topic: String): Seq, tree.tpe=(topic: String)Seq
      Apply( // final def $asInstanceOf[T0 >: ? <: ?](): T0 in class Object, tree.tpe=String
        TypeApply( // final def $asInstanceOf[T0 >: ? <: ?](): T0 in class Object, tree.tpe=()String
          "v1"."$asInstanceOf" // final def $asInstanceOf[T0 >: ? <: ?](): T0 in class Object, tree.tpe=[T0 >: ? <: ?]()T0
          <tpt> // tree.tpe=String
        )
        Nil
      )
    )
  )
  ValDef( // private[this] val zkClient$3: org.I0Itec.zkclient.ZkClient
    private <local> <synthetic> <paramaccessor> <triedcooking>
    "zkClient$3"
    <tpt> // tree.tpe=org.I0Itec.zkclient.ZkClient
    <empty>
  )
  DefDef( // def <init>(zkClient$3: org.I0Itec.zkclient.ZkClient): kafka.utils.anonfun$getAllPartitions$1
    <method> <triedcooking>
    "<init>"
    []
    // 1 parameter list
    ValDef( // zkClient$3: org.I0Itec.zkclient.ZkClient
      <param> <synthetic> <triedcooking>
      "zkClient$3"
      <tpt> // tree.tpe=org.I0Itec.zkclient.ZkClient
      <empty>
    )
    <tpt> // tree.tpe=kafka.utils.anonfun$getAllPartitions$1
    Block( // tree.tpe=Unit
      // 2 statements
      Assign( // tree.tpe=Unit
        ZkUtils$$anonfun$getAllPartitions$1.this."zkClient$3" // private[this] val zkClient$3: org.I0Itec.zkclient.ZkClient, tree.tpe=org.I0Itec.zkclient.ZkClient
        "zkClient$3" // zkClient$3: org.I0Itec.zkclient.ZkClient, tree.tpe=org.I0Itec.zkclient.ZkClient
      )
      Apply( // def <init>(): scala.runtime.AbstractFunction1 in class AbstractFunction1, tree.tpe=scala.runtime.AbstractFunction1
        ZkUtils$$anonfun$getAllPartitions$1.super."<init>" // def <init>(): scala.runtime.AbstractFunction1 in class AbstractFunction1, tree.tpe=()scala.runtime.AbstractFunction1
        Nil
      )
      ()
    )
  )
)

== Expanded type of tree ==

ConstantType(value = Constant(Class))

uncaught exception during compilation: java.lang.NullPointerException

[sksamuel]

Can you isolate the code that causes this, ideally without any external deps.

[maiflai]

I'll see what we can do - it was a long shot that you'd recognise the problem just from the error message :-)

[sksamuel]

Lol no chance, I have to duplicate the problem and figure out what construct is causing the error in the AST.

[maiflai]

Well that's a piece of code I don't want to go near again.

I can fix the issue by commenting out a return inside a catch block at line 366:

      case e1: ZkBadVersionException =>
        optionalChecker match {
          case Some(checker) => //return checker(client, path, data)
          case _ => debug("Checker method is not passed skipping zkData match")
        }
        warn("Conditional update of path %s with data %s and expected version %d failed due to %s".format(path, data,
          expectVersion, e1.getMessage))
        (false, -1)
      case e2: Exception =>

I can produce a NullPointerException (but not exactly the same one) with the following:

object bob {
  def fail(): Boolean = {
    try {
      true
    } catch {
      case _ : Throwable => 
        Option(true) match {
          case Some(bool) => return bool // comment this return and instrumentation succeeds
          case _ =>
        }
        false
    }
  }
}

[sksamuel]

It's likely return statements themselves are not handled well then. I will fix this.

[sksamuel]

I can't even get it to pass with the return commented out.

[maiflai]

That's odd - jdk8, scalac 2.10.4? I'll post a full command line when I get home, sorry.

[sksamuel]

No 2.11.4 and jdk8.

On 31 January 2015 at 15:39, maiflai notifications@github.com wrote:

That's odd - jdk8, scalac 2.10.4? I'll post a full command line when I get
home, sorry.

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Reply to this email directly or view it on GitHub
#93 (comment)
.

[maiflai]

Ok, will check that too. 2.10 gave a more detailed error message so I was working from that earlier.

[maiflai]

Sorry, I was using version 1.0.2 of the plugin, and yes, that particular object passes when I use 1.0.4

I think I've managed to break 1.0.4 by adding a function call to the return:

object bob {
  def recover(it: Boolean): Boolean = it
  def fail(): Boolean = {
    try {
      true
    } catch {
      case _ : Throwable => 
        Option(true) match {
          case Some(bool) => return recover(bool) // comment this return and instrumentation succeeds
          case _ =>
        }
        false
    }
  }
}

[sksamuel]

Still Scala 2.10 or 2.11?

On 1 February 2015 at 10:39, maiflai notifications@github.com wrote:

Sorry, I was using version 1.0.2 of the plugin, and yes, that particular
object passes when I use 1.0.4

I think I've managed to break 1.0.4 by adding a function call to the
return:

object bob {
def recover(it: Boolean): Boolean = it
def fail(): Boolean = {
try {
true
} catch {
case _ : Throwable =>
Option(true) match {
case Some(bool) => return recover(bool) // comment this return and instrumentation succeeds
case _ =>
}
false
}
}
}

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#93 (comment)
.