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Date: Tue, 27 May 2025 21:54:22 -0700
Message-ID: <CALaXqqSLYAabADg_CfZkqRAnjtXvv=BnBX-=ceiLnEZFHc=z6w@mail.gmail.com>
Subject: Re: [PHP-DEV] #[Deprecated] Attribute
To: Ben Ramsey <ramsey@php.net>
Cc: PHP Internals <internals@lists.php.net>
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From: daniel.e.scherzer@gmail.com (Daniel Scherzer)

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On Tue, May 27, 2025 at 9:41=E2=80=AFPM Ben Ramsey <ramsey@php.net> wrote:

>
> Last night, I identified a need for `#[Deprecated]` on a userland class i=
n
> one of my libraries, but I had to settle on `@deprecated` for the widest
> range of compatibility.
>
> Has there been anymore thought on putting together an implementation for
> this? I=E2=80=99m happy to draft an RFC if someone is able to help with t=
he
> implementation. I don=E2=80=99t understand the complexities around the
> implementation, but is this something that could make it into 8.5, provid=
ed
> an RFC vote passes?
>
> Cheers,
> Ben
>
>

I'd be willing to work on the implementation, but what I'm wondering is
what exactly it would mean to deprecate a class. Without a clear idea of
the goal, I didn't include this in
https://news-web.php.net/php.internals/127305 even though I had considered
it. Would a deprecated class

* Emit warnings when constructed? Just deprecate the constructor,
https://3v4l.org/DNrqm
* Emit warnings when used as a type? But we allow types to include classes
that don't exist (https://3v4l.org/pdkbv) so needing to look up the types
that are declared to emit warnings (rather than just when used to verify
that the type is respected) would presumably have a performance impact.
* Emit warnings when extended? I suggested that in my email a few weeks
ago, and when I have time I was going to look into that - I was thinking
something like `#[\WillBeFinal]` that would work for classes, methods,
properties, and constants, and would emit warnings just like
`#[\Deprecated]` but not when a method is called or a constant is used,
just when things are overridden

What were you thinking in terms of desired semantics?

 --Daniel

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<div dir=3D"ltr"><div dir=3D"ltr">On Tue, May 27, 2025 at 9:41=E2=80=AFPM B=
en Ramsey &lt;<a href=3D"mailto:ramsey@php.net">ramsey@php.net</a>&gt; wrot=
e:</div><div class=3D"gmail_quote gmail_quote_container"><blockquote class=
=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rg=
b(204,204,204);padding-left:1ex"><br>
Last night, I identified a need for `#[Deprecated]` on a userland class in =
one of my libraries, but I had to settle on `@deprecated` for the widest ra=
nge of compatibility.<br>
<br>
Has there been anymore thought on putting together an implementation for th=
is? I=E2=80=99m happy to draft an RFC if someone is able to help with the i=
mplementation. I don=E2=80=99t understand the complexities around the imple=
mentation, but is this something that could make it into 8.5, provided an R=
FC vote passes?<br>
<br>
Cheers,<br>
Ben<br>
<br></blockquote><div><br></div><div><br></div><div>I&#39;d be willing to w=
ork on the implementation, but what I&#39;m wondering is what exactly it wo=
uld mean to deprecate a class. Without a clear idea of the goal, I didn&#39=
;t include this in=C2=A0<a href=3D"https://news-web.php.net/php.internals/1=
27305">https://news-web.php.net/php.internals/127305</a> even though I had =
considered it. Would a deprecated class</div><div><br></div><div>* Emit war=
nings when constructed? Just deprecate the constructor,=C2=A0<a href=3D"htt=
ps://3v4l.org/DNrqm">https://3v4l.org/DNrqm</a></div><div>* Emit warnings w=
hen used as a type? But we allow types to include classes that don&#39;t ex=
ist (<a href=3D"https://3v4l.org/pdkbv">https://3v4l.org/pdkbv</a>) so need=
ing to look up the types that are declared to emit warnings (rather than ju=
st when used to verify that the type is respected) would presumably have a =
performance impact.</div><div>* Emit warnings when extended? I suggested th=
at in my email a few weeks ago, and when I have time I was going to look in=
to that - I was thinking something like `#[\WillBeFinal]` that would work f=
or classes, methods, properties, and constants, and would emit warnings jus=
t like `#[\Deprecated]` but not when a method is called or a constant is us=
ed, just when things are overridden</div><div><br></div><div>What were you=
=C2=A0thinking in terms of desired semantics?</div><div><br></div><div>=C2=
=A0--Daniel=C2=A0</div></div></div>

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