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Date: Sun, 23 Sep 2018 23:48:22 +0200
Message-ID: <CAF+90c9qzq+BspSH-UTOM5xhk_1h6XfGegpQLhndbGf31BhBrQ@mail.gmail.com>
To: Rowan Collins <rowan.collins@gmail.com>
Cc: PHP internals <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="00000000000097d4d6057690d542"
Subject: Re: [PHP-DEV] [RFC] [VOTE] Typed properties v2
From: nikita.ppv@gmail.com (Nikita Popov)

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On Sun, Sep 23, 2018 at 10:08 PM Rowan Collins <rowan.collins@gmail.com>
wrote:

> On 23/09/2018 19:41, Claude Pache wrote:
> >> 3) Object properties may be type hinted and the class author has until
> the end
> >> of the constructor to make sure they're fulfilled, otherwise TypeError
> on the
> >> spot (what I'm proposing).
> > Just to be sure you don=E2=80=99t miss the herd that this elephant is c=
oncealing:
> >
> > In addition, you *must* forbid unset() on those properties...
>
>
> We "must" forbid this IF we aim to guarantee that the object never has
> uninitialised properties; but the current consensus is that we can't
> make such a guarantee without changing a lot of other parts of the
> language.
>
> There are strong feelings that unset should be available for use in
> lazy-initialisation hacks, so this is likely to remain one of the
> back-doors which will let elephants in, unless and until someone comes
> up with a replacement for that hack.
>

There might be a compromise here, which is to only perform a ctor
initialization check and forbid explicit unset()s if the class does not use
property accessors (i.e. does not define __get). This allows the lazy
initialization pattern but is stricter for everything else. (Possibly __get
in subclasses would also count.)

Nikita

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