[GROOVY-7861] asType(null) called in @CompileStatic method returns a string 'null'

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.4.7
• Fix Version/s: 5.0.0-alpha-3
• Component/s: Static compilation
• Environment: Win, jdk1.7.79
• Assignee: Eric Milles
• Reporter: Jacek Karas
• Created: 13/Jun/16 20:58
• Updated: 22/Dec/23 11:38
• Resolved: 17/Oct/23 21:40

Description

The following code:

import groovy.transform.CompileStatic
class Test {
    @CompileStatic
    static Object castToType(Object o, Class clazz) { 
        return o.asType(clazz)
    }
}
def foo = Test.castToType(null, String.class)
println "'${foo}' class: ${foo.getClass()} bytes: ${foo?.getBytes()}"

prints:

'null' class: class java.lang.String bytes: [110, 117, 108, 108]

i.e. the method annotated with @CompileStatic converts null to the actual string 'null' (which is quite a nasty surprise when trying to "speed things up" by adding @CompileStatic to existing non-static code).

The same without @CompileStatic returns:

'null' class: class org.codehaus.groovy.runtime.NullObject bytes: null

as expected.