On Fri, May 31, 2024, at 5:45 PM, Claude Pache wrote:
>> Le 31 mai 2024 à 18:08, Larry Garfield <[email protected]> a écrit :
>>
>> However, this also brings up another interesting issue: readonly properties (in 8.3) DO
>> allow redeclaration, essentially adjusting the property scope (the class that declares it) to make
>> the visibility check pass. That is, the definition of the class it is private to changes, which is
>> different from how inheritance works elsewhere. When the parent writes to the same property, a
>> special check is needed to verify the two properties are related. All that special casing
>> effectively means that readonly in 8.4 wouldn't really be "write once +
>> private(set)", but "write once + private(set) - final", which is... just kinda
>> screwy. That means our options are:
>>
>> * A BC break on readonly (not allowing it to be overridden)
>> * Make readonly an exception to the implicit final.
>> * Just don't allow readonly with aviz after all.
>
> Another possible option is:
>
> * Make readonly be protected(set) by default.
>
> That would weaken the originally intended semantics of readonly, but in
> a compatible and acceptable way?
>
> —Claude
Only sort of compatible. It would allow readonly props to be redefined, and wouldn't break any
existing code, I think... but it would mean any time you use readonly, suddenly a child class can
come along and mess with it out from under you.
In practice that's likely not a common concern, but it is a behavior change. I think it's
possible (I need to confirm with Ilija), if we want that slight BC break, but I don't know if
we do.
--Larry Garfield