With Spoofax 2.0b1, I can’t seem to either clean or build my project. It exits with an unhelpful NullPointerException. A clean checkout from Git does work. Stack trace is as follows:

Errors running builder ‘Integrated External Tool Builder’ on project ‘MiniJava’.

java.lang.NullPointerException
	at org.eclipse.core.externaltools.internal.launchConfigurations.ExternalToolsCoreUtil.isBuilderEnabled(ExternalToolsCoreUtil.java:169)
	at org.eclipse.core.externaltools.internal.model.ExternalToolBuilder.configEnabled(ExternalToolBuilder.java:155)
	at org.eclipse.core.externaltools.internal.model.ExternalToolBuilder.clean(ExternalToolBuilder.java:288)
	at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:736)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:205)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:245)
	at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:300)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:303)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:359)
	at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:382)
	at org.eclipse.core.internal.resources.Workspace.buildInternal(Workspace.java:486)
	at org.eclipse.core.internal.resources.Workspace.build(Workspace.java:398)
	at org.eclipse.ui.internal.ide.dialogs.CleanDialog.doClean(CleanDialog.java:318)
	at org.eclipse.ui.internal.ide.dialogs.CleanDialog$1.runInWorkspace(CleanDialog.java:153)
	at org.eclipse.core.internal.resources.InternalWorkspaceJob.run(InternalWorkspaceJob.java:39)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)

Session data:

eclipse.buildId=4.5.2.M20160212-1500
java.version=1.7.0_72
java.vendor=Oracle Corporation
BootLoader constants: OS=macosx, ARCH=x86_64, WS=cocoa, NL=en_US
Framework arguments:  -product org.eclipse.epp.package.java.product -keyring /Users/XXX/.eclipse_keyring -showlocation
Command-line arguments:  -os macosx -ws cocoa -arch x86_64 -product org.eclipse.epp.package.java.product -keyring /Users/XXX/.eclipse_keyring -showlocation

Submitted by mhjc on 3 June 2016 at 12:06

Layer 8 error: a Spoofax 1.5 project still showed up in my editor, which caused the error.