[JEXL-281] MethodExecutor incorrectly tests for empty parameters list

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.1
• Fix Version/s: 3.2
• Assignee: Henri Biestro
• Reporter: Mirek Hankus
• Created: 12/Dec/18 18:34
• Updated: 07/Jun/21 13:14
• Resolved: 17/Dec/18 15:45

Description

Currently MethodExecutor constructor contains code 

if (method != null) {
    Class<?>[] formal = method.getParameterTypes();
    // if the last parameter is an array, the method is considered as vararg
    if (formal != null && MethodKey.isVarArgs(method)) {
        vastart = formal.length - 1;
        vaclass = formal[vastart].getComponentType();
    }
}

variable formal is never null, beacause Javadoc for getParameterTypes  states that  "returns an array of length 0 if the underlying executable takes no parameters." (implementation invokes  clone - so there always be an object)

So test for empty parameter list  should not test for null, but for empty array - 

if (formal.length > 0 && MethodKey.isVarArgs(method)) {

.

Problem is that MethodKey.isVarArgs is very costly (it traverses class hierarchy, and throws Exception for every object which does not have method by this name) - so invocation of isVarArgs should be avoided if not required. Currently it is always called due to wrong test condition

 

 

 

Issue Links

• fixes: JEXL-343 MethodExecutor ctor has strange null check before calling MethodKey.isVarArgs()