Can Your Exception Handling Code Handle the SchrodingerException Juggernaut?
I was writing some documentation for Aloha the other day when I thought some more about an exception that I wrote called SchrodingerException after the Erwin Schrödinger, the Nobel Prize-winning physicist that gave us many cool things like Schrödinger equation. He’s perhaps most well known in popular culture for his famous Schrödinger cat thought experiment. You can read about it yourself but the punchline is that there is a cat in a box and you can’t know if it’s alive or dead until observing it. So it’s kind of in a half live, half dead state.
Out of an excessive amount sadism, I’ve chosen to pervert the meaning of the thought experiment a little. So SchrodingerException actually kills the cat every time. It’s as if opening the box releases the hydrocyanic acid. What this means is that when the exception is interrogated in any way, it throws itself:
If you try to get the message, it throws itself!
If you try to get the Throwable caused it, it throws itself!
If you try to get the stacktrace, it throws itself!
If you try to print the stacktrace, it throws itself!
If you call toString, it throws itself!
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// Scala Code
import java.io.{PrintWriter, PrintStream}
final class SchrodingerException(message: String, cause: Throwable)
extends Exception(message, cause) {
def this() = this(null, null)
def this(message: String) = this(message, null)
def this(cause: Throwable) = this(null, cause)
override def fillInStackTrace() = this
override def getCause() = throw this
override def getLocalizedMessage() = throw this
override def getMessage() = throw this
override def getStackTrace() = throw this
override def initCause(cause: Throwable) = throw this
override def printStackTrace() = throw this
override def printStackTrace(s: PrintStream) = throw this
override def printStackTrace(s: PrintWriter) = throw this
override def setStackTrace(stackTrace: Array[StackTraceElement]) =
throw this
override def toString() = throw this
def safeToString() = {
val m = Option(message) getOrElse ""
s"SchrodingerException($m)"
}
}
I wrote this exception so that I could test the ErrorSwallowingModel in Aloha which is supposed to swallow thrown exceptions and return the errors instead (like functional code should).