`NullPointerException` when ran with `-P`

[gabrielfeo]

It was reported that, given this invocation, script n. 1 failed with an exception. I don't have a reproducer at this time.

./01-validate-local-build-caching-same-location.sh -r file:///home/example/repo -b example-branch -g install -a -P\ lorem\,ipsum\,foo\,bar

[ERROR] Error executing a DevelocityListener callback
java.lang.NullPointerException: Cannot invoke "java.util.Collection.size()" because "c" is null
    at java.util.LinkedHashSet.<init> (LinkedHashSet.java:181)
    at com.gradle.RootProjectExtractor.discoverAllProjects (RootProjectExtractor.java:61)
    at com.gradle.RootProjectExtractor.extractRootProject (RootProjectExtractor.java:31)
    at com.gradle.ConfigureDevelocityAdaptor.configure (ConfigureDevelocityAdaptor.java:48)
    at com.gradle.ConfigureDevelocityListener.configure (ConfigureDevelocityListener.java:21)
    at com.gradle.maven.internal.DevelocityLifecycleManager.a (SourceFile:400)
    at java.lang.Iterable.forEach (Iterable.java:75)
    at java.util.Collections$UnmodifiableCollection.forEach (Collections.java:1116)
    at com.gradle.maven.internal.DevelocityLifecycleManager.b (SourceFile:398)
    at com.gradle.maven.internal.DevelocityLifecycleManager.c (SourceFile:370)
    at java.util.stream.ForEachOps$ForEachOp$OfRef.accept (ForEachOps.java:184)
    at java.util.stream.ReferencePipeline$15$1.accept (ReferencePipeline.java:541)
    at java.util.stream.IntPipeline$1$1.accept (IntPipeline.java:180)
    at java.util.stream.Streams$RangeIntSpliterator.forEachRemaining (Streams.java:104)
    at java.util.Spliterator$OfInt.forEachRemaining (Spliterator.java:712)
    at java.util.stream.AbstractPipeline.copyInto (AbstractPipeline.java:509)
    at java.util.stream.AbstractPipeline.wrapAndCopyInto (AbstractPipeline.java:499)
    at java.util.stream.ForEachOps$ForEachOp.evaluateSequential (ForEachOps.java:151)
    at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential (ForEachOps.java:174)
    at java.util.stream.AbstractPipeline.evaluate (AbstractPipeline.java:234)
    at java.util.stream.ReferencePipeline.forEach (ReferencePipeline.java:596)
    at com.gradle.maven.internal.DevelocityLifecycleManager.a (SourceFile:370)
    at com.gradle.maven.internal.DevelocityLifecycleManager.onEvent (SourceFile:313)
    at org.apache.maven.eventspy.internal.EventSpyDispatcher.onEvent (EventSpyDispatcher.java:86)
    at org.apache.maven.cli.MavenCli.execute (MavenCli.java:908)
    at org.apache.maven.cli.MavenCli.doMain (MavenCli.java:283)
    at org.apache.maven.cli.MavenCli.main (MavenCli.java:206)
    at jdk.internal.reflect.DirectMethodHandleAccessor.invoke (DirectMethodHandleAccessor.java:103)
    at java.lang.reflect.Method.invoke (Method.java:580)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced (Launcher.java:283)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch (Launcher.java:226)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode (Launcher.java:407)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main (Launcher.java:348)