This issue is resolved in 3.x and is essentially backported from 47d106c which was part of GROOVY-8279.

This issue ends up being a problem for Apache TinkerPop which relies on groovysh fairly heavily. Without this change, a fail within shell.parse() within the try block leaves the type as null and then provides that argument to removeClassCacheEntry(). At that point no matter what exception shell.parse() threw, the Interpreter.evaluate() will end up throwing a NullPointerException thus masking the error. In our case at TinkerPop, the exception typically masked is a StackOverflowError which would be much more useful than the NullPointerException as it would point to a common specific problem that we could alert users to more readily.