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Message-ID: <571E4A83.3080304@garfieldtech.com>
Date: Mon, 25 Apr 2016 11:49:07 -0500
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Subject: Re: [PHP-DEV] [RFC] PHP Attributes
From: larry@garfieldtech.com (Larry Garfield)

On 04/25/2016 10:20 AM, Dmitry Stogov wrote:
>
>> This leads to some serious copy/paste, highly error prone... =(
>
> If we had a theoretical approach for attribute inheritance, I would 
> implement it.
> But I wouldn't invite any theory, because anyone is going to depend on 
> use-case.

Realistically, I see only 3 possible approaches to consider:

1) An overridden class/property/method always inherits its parent's 
annotations/attributes, and you can add to them.
2) An overridden class/property/method never inherits its parent's 
annotations/attributes, but you can repeat them.
3) Give users a syntactic toggle.

>> As I said earlier, if you do a call based approach, we could create 
>> @Inherit or @Override, which would not only make us safe from 
>> support, but also gives more power to developers.
>
> If we implement built-in @Inherit and/or @Override, it's not a big 
> problem to copy attributes from parent.

If I understand you correctly, that would be option 3.  I would support 
that as well, as it's consistent with how methods work: By default, they 
override the parent method but you can call parent::whatever() to toggle 
the parent behavior back on.  Thus, I would suggest that when overriding 
a class/property/method that has annotations, it NOT inherit 
annotations/attributes by default. However, by adding an annotation of

<<__inherit>>

(Or some other internal-reserved keyword, I don't have strong feelings 
on what it is) then the engine will automatically give you all the 
annotations off of the parent, and union them with whatever additional 
ones you add.

That of course raises interesting questions around interfaces and 
traits, and how annotations on those comingle.  Should annotations on 
interfaces auto-apply to their implementations or should they require an 
explicit <<__inherit>>?  I'm undecided.

--Larry Garfield