NullPointerException in ST4 ErrorManager.compileTimeError

[steinybot]

steps

sbt or Giter8 version: 0.12.1-SNAPSHOT

❯ /Users/jason/.conscript/bin/g8 BotTech/sbt-autoplugin.g8 -b bottech

sbt plugin seed

pluginName [Foo Bar]: Turtles
name [sbt-turtles]:
organizationName [BotTech]:
organization [nz.co.bottech]:
package [nz.co.bottech.sbt.turtles]:
purpose [An sbt plugin]: An sbt plugin for sharing settings between the meta-builds and the main build.
sbtVersion [1.3.10]:
scalaVersion [2.12.11]:
scalacticVersion [3.1.1]:
uTestVersion [0.7.4]:

problem

The root cause is a SYNTAX ERROR:

'" =~ 2.1[2]..* && "' came as a complete surprise to me

This is then causing a NPE to be thrown when ST4 tries to report the error.

stack trace

java.lang.NullPointerException
	at org.stringtemplate.v4.misc.ErrorManager.compileTimeError(ErrorManager.java:100)
	at org.stringtemplate.v4.compiler.Compiler.reportMessageAndThrowSTException(Compiler.java:205)
	at org.stringtemplate.v4.compiler.Compiler.compile(Compiler.java:149)
	at org.stringtemplate.v4.STGroup.compile(STGroup.java:514)
	at org.stringtemplate.v4.ST.<init>(ST.java:173)
	at giter8.G8$.applyTemplate(g8.scala:134)
	at giter8.G8$.write(g8.scala:185)
	at giter8.G8$.write(g8.scala:170)
	at giter8.G8$.$anonfun$writeTemplates$3(g8.scala:502)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
	at scala.util.control.Exception$Catch.$anonfun$opt$1(Exception.scala:246)
	at scala.util.control.Exception$Catch.apply(Exception.scala:228)
	at scala.util.control.Exception$Catch.opt(Exception.scala:246)
	at giter8.G8$.$anonfun$writeTemplates$2(g8.scala:502)
	at scala.collection.immutable.Stream.foreach(Stream.scala:533)
	at giter8.G8$.writeTemplates(g8.scala:488)
	at giter8.G8$.$anonfun$applyT$1(g8.scala:344)
	at scala.util.Either$RightProjection.flatMap(Either.scala:701)
	at giter8.G8$.applyT(g8.scala:327)
	at giter8.G8$.fromDirectory(g8.scala:76)
	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 giter8.Giter8.run(giter8.scala:30)
	at giter8.Giter8.run(giter8.scala:26)
	at giter8.Giter8.run(giter8.scala:22)
	at xsbt.boot.Launch$$anonfun$run$1.apply(Launch.scala:109)
	at xsbt.boot.Launch$.withContextLoader(Launch.scala:128)
	at xsbt.boot.Launch$.run(Launch.scala:109)
	at xsbt.boot.Launch$$anonfun$apply$1.apply(Launch.scala:35)
	at xsbt.boot.Launch$.launch(Launch.scala:117)
	at xsbt.boot.Launch$.apply(Launch.scala:18)
	at xsbt.boot.Boot$.runImpl(Boot.scala:56)
	at xsbt.boot.Boot$.main(Boot.scala:18)
	at xsbt.boot.Boot.main(Boot.scala)

Unknown exception: null

expectation

notes

A guard was put in ST4 a long time ago but it was not put in all the right places: https://github.com/antlr/stringtemplate4/commit/7bff6cf014408927b1db4b92406996172f8442e5

[eed3si9n]

Should we put our own NPE guard here?

[steinybot]

That would be a good idea as a temporary measure. See #461.

[TonioGela]

@steinybot, how do you think we can proceed? The workaround works, and the PR on ST4 was merged. Can we close it, or is it something else to do? Plus ST4 4.3.1 was released and it was added to giter8 here so technically your fix should now be included.