Thanks for the additional reference. Also, GROOVY-9596 helps provide some
additional context.
When considering "this.x" and "super.x" where "x" in both cases is a field or
property of the super class, I can understand the desire for consistent
handling. When "x" is a member in the current class, direct field access seems
intuitive to me; OC raises some concern. When "x" is a member of the current
class and a subclass, things start to get complicated.
class A {
def x = 1
def m() { x }
}
class B extends A {
def x = 2
def getX() { 3 }
}
new B().m() // as discussed in nabble link, should this return 1 always or 2 or
3?
From: OCsite <[email protected]>
Sent: Friday, June 26, 2020 9:05 AM
To: [email protected]
Subject: Re: "super" object expression for attribute, property, and method call
Hi there,
note please that IMO, this.foo definitely should go through the getFoo getter
if there's one; that is does not happen currently I regard as a pretty grave
bug, for it breaks encapsulation. Compare please e.g.
http://groovy.329449.n5.nabble.com/Inconsistency-properties-are-accessed-as-fields-within-class-td5721135.html<https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2Fgroovy.329449.n5.nabble.com%2FInconsistency-properties-are-accessed-as-fields-within-class-td5721135.html&data=02%7C01%7Ceric.milles%40thomsonreuters.com%7C35cf6bc94b5f42409c5008d819d9ed9a%7C62ccb8646a1a4b5d8e1c397dec1a8258%7C0%7C0%7C637287771073872731&sdata=xDdyhOMe%2BFjNNGnW7Ajmm5Ehw2gUF93PTxonfb1fDEM%3D&reserved=0>
All the best,
OC
On 26 Jun 2020, at 15:51, Milles, Eric (TR Tech, Content & Ops)
<[email protected]<mailto:[email protected]>> wrote:
which means [super.x] behaves different to this.x
Yes, they would be different. I always interpreted this behavior as
"references to a class member within the declaring class are direct accesses".
For me, "super.x" is not a reference to a member from the declaring class, so
MOP is okay/expected. Indeed, there are bugs cited that expect "super.x" to
drive getX() or isX() in the parent class.
Is there an explicit definition of explicit "this" and "super" qualifiers with
regards to fields? I'm going off intuition and experience. GROOVY-8999 tries
to show that there is not consistent behavior and so it is hard to fully
understand what can be expected when using the super qualifier.
I will proceed with proposed changes to "super.@x" and the error messages.
Those items don't seem controversial.
-----Original Message-----
From: Jochen Theodorou <[email protected]<mailto:[email protected]>>
Sent: Thursday, June 25, 2020 11:56 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: "super" object expression for attribute, property, and method call
On 25.06.20 23:34, Milles, Eric (TR Tech, Content & Ops) wrote:
The handling for "this" and "super" are separate enough that we could support
different behaviors. I think I am looking to make 2 changes to start with:
1) super.@x cannot access a private field and does not try getX(), isX() or any
other alternatives. STC should produce an error for this case. Currently, if
the field is not accessible, "super.getX()" is substituted and so errors for
"no getX() method" can be confusing.
2) super.x does not bypass accessor methods. So getX() if it exists, isX() if
its boolean, field if field is accessible and no accessor exists, and finally
propertyMissing/MissingPropertyException.
As you stated below, #1 is a breaking change. Today an inaccessible super.@x
produces a super.getX() substitution. And I think #2 is a refinement; if user
wants to bypass the accessor method, super.@x is and has been available.
which means it behaves different to this.x
I suppose the third change is that when "super.x" fails, the compiler says "No
such property x for B" when A is really the start of the search. Fixing the
error messages would also be beneficial.
+1
I'm not proposing to enable access to private fields, just improve the
consistency of errors and remove workarounds that IMO go against the spirit of
".@" operator.
this has been a story in the past for dynamic Groovy, which is why I mentioned
it explicitly
bye Jochen
