[GROOVY-9348] Introduce finer control for AS keyword with maps

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.5.8
• Component/s: Compiler, Static compilation, Static Type Checker
• Labels: cast

Docs Text

Given the following classes:

class A {
    B b
    int data
    int data2
}
class B {
    C c
    String data
}
class C {
    Date data
}

The code works fine:

Date now = new Date()
def a = [ data:42, data2:84, b:[ data:'BBB', c:[ data:now ] ] ] as A
assert a.b.c.data == now
assert a.data == 42
assert a.data2 == 84

Now if I omit the data2:84, the code still works fine except for the last assert of course.

BUT! If I "misspell" the property name like:

def a = [ data:42, data22:84, b:[ data:'BBB', c:[ data:now ] ] ] as A

The 1st assert fails with NPE:

    java.lang.NullPointerException: Cannot get property 'c' on null object

and what I see is that only the A class gets instantiated with a no-arg constructor, and b and c properties are all nulls.

To make the behaviour more persistent I can see the following options:

* do hard-stop: throw an UnknownPropertyException in case of unknown property
* do the best-effort cast, i.e. skip the unknown properties only, and fill-in the good ones
* provide a control mechanism to switch between the current "silent" behaviour, maybe by introducing new keywords _asStrict_ and _asLenient_

The case is discussed in https://stackoverflow.com/questions/59423991/groovy-as-keyword-for-map-class-binding

• Assignee: Unassigned
• Reporter: Konstantin Smirnov
• Created: 20/Dec/19 14:15
• Updated: 21/Dec/19 22:10