[GROOVY-10009] TracingInterceptor throws NullPointerException if arguments contains a null argument

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.5, 3.0.6
• Fix Version/s: 4.0.0-alpha-3, 3.0.9
• Component/s: groovy-jdk
• Environment: Windows 10 Pro
• Assignee: Eric Milles
• Reporter: John Yin
• Created: 05/Apr/21 14:11
• Updated: 17/Aug/21 16:49
• Resolved: 11/Apr/21 15:47

Description

If a method is called with an argument having null value, beforeInvoke throws a NullPointerException.  Here is an example:

class Foo {
   String say(String s)

Unknown macro: {      return s    }

}

Foo foo = new Foo()

def tracer = new TracingInterceptor()
def proxyMetaClass = ProxyMetaClass.getInstance(Foo.class)
proxyMetaClass.interceptor = tracer
foo.metaClass = proxyMetaClass

def s
foo.say(s)

This will cause a crash because s is null.  I believe inside writeInfo() method of TracingInterceptor, it has something like argument.getClass(). 

In the example above, if we change foo.say(s) to foo.say(s as String) it would pass the beforeInvoke but still fails afterward.  If we actual set s to a non-null value, e.g.

def s = 'Hello'

the trace would work.