https://github.com/jrudolph/better-future-exceptions

A POC for better exception reporting for futures
https://github.com/jrudolph/better-future-exceptions

Last synced: 25 days ago
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A POC for better exception reporting for futures

• Host: GitHub
• URL: https://github.com/jrudolph/better-future-exceptions
• Owner: jrudolph
• Created: 2013-07-16T10:22:32.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2014-08-20T14:26:34.000Z (about 10 years ago)
• Last Synced: 2023-04-11T05:18:11.219Z (over 1 year ago)
• Language: Scala
• Size: 137 KB
• Stars: 12
• Watchers: 2
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

README

        
Demo for better exception reporting for futures (macro-based)

When futures fail exceptions often contain too little context to determine the path of

composition leading to the error. This is a proof-of-concept how to use static source code 

context info gathered through a macro (basically a simple implementation of SIP-19 with macros)

to annotate exceptions with the composition path.

Example

-------

```scala

import scala.concurrent.ExecutionContext

object FutureTest extends App {

  import scala.concurrent.ExecutionContext.Implicits.global

  //import scala.concurrent.{ Future => RichFuture }

  object Transformer {

    def div0(f: RichFuture[Int])(implicit ctx: ExecutionContext): RichFuture[Int] =

      f.flatMap { i =>

        val j = i / 0

        RichFuture { Thread.sleep(1000); j + 12 } }

  }

  val f = RichFuture {

    Thread.sleep(2000)

    42

  }

  val res = Transformer.div0(f)

  res.onComplete {

    case e => println("Finished with: "+e)

  }

  Thread.sleep(5000)

}

```

prints

```

Finished with: Failure(net.virtualvoid.futures.RichFutureException: Exception '/ by zero' in future called through this stack: 

CallInfo(CallSite(net.virtualvoid.futures.FutureTest.Transformer,Some(div0),FutureTest.scala,13),flatMap)

CallInfo(CallSite(net.virtualvoid.futures.FutureTest,None,FutureTest.scala,19),RichFuture())

)

```

This demo was prompted by a [thread on scala-user](https://groups.google.com/d/topic/scala-user/BjgQpWeqA0w/discussion).