StepAvailable: if 'step' is null, return false

[josteinaj]

I'm getting a NullPointerException in StepAvailable.java:

java.lang.NullPointerException
	at com.xmlcalabash.functions.StepAvailable$StepAvailableCall.call(StepAvailable.java:121) ~[xmlcalabash-1.1.15-96.jar:1.1.15-96]
	at net.sf.saxon.lib.ExtensionFunctionCall.effectiveBooleanValue(ExtensionFunctionCall.java:208) ~[Saxon-HE-9.6.0-4.jar:?]
	at net.sf.saxon.functions.IntegratedFunctionCall.effectiveBooleanValue(IntegratedFunctionCall.java:318) ~[Saxon-HE-9.6.0-4.jar:?]
	at net.sf.saxon.functions.BooleanFn.effectiveBooleanValue(BooleanFn.java:159) ~[Saxon-HE-9.6.0-4.jar:?]
	at net.sf.saxon.functions.BooleanFn.evaluateItem(BooleanFn.java:150) ~[Saxon-HE-9.6.0-4.jar:?]
	at net.sf.saxon.functions.BooleanFn.evaluateItem(BooleanFn.java:28) ~[Saxon-HE-9.6.0-4.jar:?]
	at net.sf.saxon.expr.Expression.iterate(Expression.java:448) ~[Saxon-HE-9.6.0-4.jar:?]
	at net.sf.saxon.sxpath.XPathExpression.iterate(XPathExpression.java:175) ~[Saxon-HE-9.6.0-4.jar:?]
	at net.sf.saxon.s9api.XPathSelector.iterator(XPathSelector.java:200) ~[Saxon-HE-9.6.0-4.jar:?]
	at com.xmlcalabash.runtime.XAtomicStep.evaluateXPath(XAtomicStep.java:856) ~[xmlcalabash-1.1.15-96.jar:1.1.15-96]
	at com.xmlcalabash.runtime.XWhen.shouldRun(XWhen.java:43) ~[xmlcalabash-1.1.15-96.jar:1.1.15-96]
	at com.xmlcalabash.runtime.XChoose.run(XChoose.java:107) ~[xmlcalabash-1.1.15-96.jar:1.1.15-96]
	at com.xmlcalabash.runtime.XPipeline.doRun(XPipeline.java:236) ~[xmlcalabash-1.1.15-96.jar:1.1.15-96]
	at com.xmlcalabash.runtime.XPipeline.run(XPipeline.java:136) ~[xmlcalabash-1.1.15-96.jar:1.1.15-96]
	at com.xmlcalabash.runtime.XPipelineCall.run(XPipelineCall.java:94) ~[xmlcalabash-1.1.15-96.jar:1.1.15-96]
	at com.xmlcalabash.runtime.XPipeline.doRun(XPipeline.java:236) ~[xmlcalabash-1.1.15-96.jar:1.1.15-96]
	at com.xmlcalabash.runtime.XPipeline.run(XPipeline.java:136) ~[xmlcalabash-1.1.15-96.jar:1.1.15-96]
	at com.xmlcalabash.drivers.Main.run(Main.java:365) ~[xmlcalabash-1.1.15-96.jar:1.1.15-96]
	at com.xmlcalabash.drivers.Main.run(Main.java:112) [xmlcalabash-1.1.15-96.jar:1.1.15-96]
	at com.xmlcalabash.drivers.Main.main(Main.java:83) [xmlcalabash-1.1.15-96.jar:1.1.15-96]

I haven't been able to reproduce it as a test in the test suite. However, checking for null and returning false in case of null seems to work in my case. If you want to reproduce, follow the "getting started" part for xprocspec with Calabash 1.0.32 or newer.

[ndw]

Merged manually. Fixed. Thank you!