Null Pointer Exception when using Control+D to send EOF to user input

[lalaithion]

steps

sbt 1.5.2

problem

Running a command like sbt new scala/scala3.g8 fails with this stack trace:

java.lang.NullPointerException
	at giter8.G8$.$anonfun$interact$3(g8.scala:471)
	at scala.collection.LinearSeqOptimized.foldLeft(LinearSeqOptimized.scala:126)
	at scala.collection.LinearSeqOptimized.foldLeft$(LinearSeqOptimized.scala:122)
	at scala.collection.immutable.List.foldLeft(List.scala:89)
	at giter8.G8$.interact(g8.scala:460)
	at giter8.G8$.$anonfun$applyT$2(g8.scala:341)
	at scala.Option.getOrElse(Option.scala:189)
	at giter8.G8$.$anonfun$applyT$1(g8.scala:341)
	at scala.util.Either$RightProjection.flatMap(Either.scala:701)
	at giter8.G8$.applyT(g8.scala:338)
	at giter8.G8$.fromDirectory(g8.scala:77)
	at giter8.G8TemplateRenderer$.render(TemplateRenderer.scala:40)
	at giter8.AppProcessor.process(giter8.scala:58)
	at giter8.Runner.$anonfun$run$9(Runner.scala:51)
	at scala.util.Either.flatMap(Either.scala:341)
	at giter8.Runner.$anonfun$run$5(Runner.scala:48)
	at scala.util.Either.flatMap(Either.scala:341)
	at giter8.Runner.$anonfun$run$4(Runner.scala:47)
	at scala.util.Either.flatMap(Either.scala:341)
	at giter8.Runner.run(Runner.scala:46)
	at giter8.Giter8.run(giter8.scala:33)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at giter8.LauncherProcessor.call(LauncherMain.scala:114)
	at giter8.LauncherProcessor.virtuallyRun(LauncherMain.scala:88)
	at giter8.LauncherProcessor.process(LauncherMain.scala:38)
	at giter8.Runner.$anonfun$run$9(Runner.scala:51)
	at scala.util.Either.flatMap(Either.scala:341)
	at giter8.Runner.$anonfun$run$5(Runner.scala:48)
	at scala.util.Either.flatMap(Either.scala:341)
	at giter8.Runner.$anonfun$run$4(Runner.scala:47)
	at scala.util.Either.flatMap(Either.scala:341)
	at giter8.Runner.run(Runner.scala:46)
	at giter8.Runner.run(Runner.scala:72)
	at sbtgiter8resolver.Giter8TemplateResolver.run(Giter8TemplateResolver.scala:34)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at sbt.TemplateCommandUtil$.call(TemplateCommandUtil.scala:113)
	at sbt.TemplateCommandUtil$.runTemplate(TemplateCommandUtil.scala:88)
	at sbt.TemplateCommandUtil$.$anonfun$run$1(TemplateCommandUtil.scala:64)
	at sbt.TemplateCommandUtil$.$anonfun$run$1$adapted(TemplateCommandUtil.scala:60)
	at scala.collection.LinearSeqOptimized.find(LinearSeqOptimized.scala:115)
	at scala.collection.LinearSeqOptimized.find$(LinearSeqOptimized.scala:112)
	at scala.collection.immutable.List.find(List.scala:91)
	at sbt.TemplateCommandUtil$.run(TemplateCommandUtil.scala:60)
	at sbt.TemplateCommandUtil$.runTemplate(TemplateCommandUtil.scala:47)
	at sbt.TemplateCommandUtil$.$anonfun$templateCommand$2(TemplateCommandUtil.scala:28)
	at sbt.Command$.$anonfun$applyEffect$4(Command.scala:150)
	at sbt.Command$.$anonfun$applyEffect$2(Command.scala:145)
	at sbt.Command$.process(Command.scala:189)
	at sbt.MainLoop$.$anonfun$processCommand$5(MainLoop.scala:245)
	at scala.Option.getOrElse(Option.scala:189)
	at sbt.MainLoop$.process$1(MainLoop.scala:245)
	at sbt.MainLoop$.processCommand(MainLoop.scala:276)
	at sbt.MainLoop$.$anonfun$next$5(MainLoop.scala:163)
	at sbt.State$StateOpsImpl$.runCmd$1(State.scala:289)
	at sbt.State$StateOpsImpl$.process$extension(State.scala:325)
	at sbt.MainLoop$.$anonfun$next$4(MainLoop.scala:163)
	at sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:23)
	at sbt.MainLoop$.next(MainLoop.scala:163)
	at sbt.MainLoop$.run(MainLoop.scala:144)
	at sbt.MainLoop$.$anonfun$runWithNewLog$1(MainLoop.scala:119)
	at sbt.io.Using.apply(Using.scala:27)
	at sbt.MainLoop$.runWithNewLog(MainLoop.scala:112)
	at sbt.MainLoop$.runAndClearLast(MainLoop.scala:66)
	at sbt.MainLoop$.runLoggedLoop(MainLoop.scala:51)
	at sbt.MainLoop$.runLogged(MainLoop.scala:42)
	at sbt.StandardMain$.runManaged(Main.scala:218)
	at sbt.xMain$.$anonfun$run$9(Main.scala:113)
	at sbt.io.IO$.withTemporaryDirectory(IO.scala:490)
	at sbt.io.IO$.withTemporaryDirectory(IO.scala:500)
	at sbt.xMain$.run(Main.scala:101)
	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 sbt.internal.XMainConfiguration.run(XMainConfiguration.java:56)
	at sbt.xMain.run(Main.scala:46)
	at xsbt.boot.Launch$.$anonfun$run$1(Launch.scala:149)
	at xsbt.boot.Launch$.withContextLoader(Launch.scala:176)
	at xsbt.boot.Launch$.run(Launch.scala:149)
	at xsbt.boot.Launch$.$anonfun$apply$1(Launch.scala:44)
	at xsbt.boot.Launch$.launch(Launch.scala:159)
	at xsbt.boot.Launch$.apply(Launch.scala:44)
	at xsbt.boot.Launch$.apply(Launch.scala:21)
	at xsbt.boot.Boot$.runImpl(Boot.scala:78)
	at xsbt.boot.Boot$.run(Boot.scala:73)
	at xsbt.boot.Boot$.main(Boot.scala:21)
	at xsbt.boot.Boot.main(Boot.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 coursier.bootstrap.launcher.a.a(Unknown Source)
	at coursier.bootstrap.launcher.Launcher.main(Unknown Source)

When entering Control+D into a user input field.

expectation

The program should gracefully exit.

[eed3si9n]

@lalaithion Thanks for the report.

I am guessing that the NPE is caused by following line

giter8/library/src/main/scala/g8.scala

Line 465 in d7f8338

val in = scala.io.StdIn.readLine().trim

where readLine() probably returns null and is blowing up at .trim.

Rather than treating it as an empty value it is throwing an exception, so it is getting the job done in a way to exit the program. Just not gracefully :)
I guess the improvement would be to wrap it in Option(...) and throw a specific exception and catch it in applyT silently:

giter8/library/src/main/scala/g8.scala

Lines 359 to 365 in 3c90ebe

	} catch {
	case e: STException =>
	Left(s"Exiting due to error in the template: ${tmpl}\n${e.getMessage}")
	case t: Throwable =>
	t.printStackTrace()
	Left("Unknown exception: " + t.getMessage)
	}

[TonioGela]

@xuwei-k or @eed3si9n can be closed, or at least it can be closed once a new version is released.