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References: <a995ac24905030e168e7f6006b996cd5@bastelstu.be> <CAPTD5yHmFW+jHz30=vAgLZJq-YFJ3+7B1oxg+DFcpsQjBt7mxQ@mail.gmail.com>
In-Reply-To: <CAPTD5yHmFW+jHz30=vAgLZJq-YFJ3+7B1oxg+DFcpsQjBt7mxQ@mail.gmail.com>
Date: Mon, 24 Feb 2025 16:34:00 +0100
Message-ID: <CAMzRQTcahp+3JaybrJrUaQ8NqR5xaVLRC7tQbkQ_j60GWn3BjQ@mail.gmail.com>
Subject: Re: [PHP-DEV] RFC: Marking return values as important (#[\NoDiscard])
To: Jorg Sowa <jorg.sowa@gmail.com>
Cc: =?UTF-8?Q?Tim_D=C3=BCsterhus?= <tim@bastelstu.be>, 
	php internals <internals@lists.php.net>
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From: volker@tideways-gmbh.com (Volker Dusch)

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On Wed, Feb 12, 2025 at 10:44=E2=80=AFPM Jorg Sowa <jorg.sowa@gmail.com> wr=
ote:

> I must agree with Kamil. I don't see practical benefits of this feature
> that would surpass the implications it has for the language. We already
> have static analysis handling such cases and it can be extended even to
> non-pure functions. Moreover, syntax (void) adds additional complexity to
> beginners' understanding of the typing system. The second option with $_ =
is
> BC on the other hand, so both options are unsatisfying. And honestly, I
> don't have good ideas for it.
>
> Kind regards,
> Jorg Sowa
>

Hi Jorg,

To be clear: There is no BC break with $_. Opcache doesn't discard
variables containing objects, so there is no observable change in behavior
from what we're proposing. It doesn't change the variable semantics at all.
Or am I misunderstanding what you're referring to?

In addition, I reached out to see if Ond=C5=99ej (Creator of PHPStan) had a=
n
opinion: https://phpc.social/@OndrejMirtes/114040888791921128 - So on top
of our previous arguments that PHP shouldn't depend on 3rd party tools for
everything, there is also at least interest in having this in core from the
tool creators.

> @edorian It already exists for PHPStan as a 3rd party extension:
https://github.com/DaveLiddament/phpstan-php-language-extensions
(MustUseResult)
> Additionally, PHPStan itself reports this if you call a @phpstan-pure
method or function and not use its result.
> This attribute would be valuable for functions that aren=E2=80=99t pure b=
ut
you=E2=80=99re still supposed to read the returned value.

Kind regards,
Volker

--
Volker Dusch
Head of Engineering
Tideways GmbH
K=C3=B6nigswinterer Str. 116
53227 Bonn
https://tideways.io/imprint

Sitz der Gesellschaft: Bonn
Gesch=C3=A4ftsf=C3=BChrer: Benjamin Au=C3=9Fenhofer (geb. Eberlei)
Registergericht: Amtsgericht Bonn, HRB 22127

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<div dir=3D"ltr"><div dir=3D"ltr"><div class=3D"gmail_quote gmail_quote_con=
tainer"><div dir=3D"ltr" class=3D"gmail_attr">On Wed, Feb 12, 2025 at 10:44=
=E2=80=AFPM Jorg Sowa &lt;<a href=3D"mailto:jorg.sowa@gmail.com">jorg.sowa@=
gmail.com</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" style=
=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding=
-left:1ex"><div dir=3D"ltr"><div><div>I must agree with Kamil. I don&#39;t =
see practical benefits of this feature that would surpass the implications =
it has for the language. We already have static analysis handling such case=
s and it can be extended even to non-pure functions. Moreover, syntax (void=
) adds additional complexity to beginners&#39; understanding of the typing =
system. The second option with $_ is BC on the other hand, so both options =
are unsatisfying. And honestly, I don&#39;t have good ideas for it.<br><br>=
</div>Kind regards,<br></div>Jorg Sowa</div></blockquote></div></div><div d=
ir=3D"ltr"><br></div><div dir=3D"ltr">Hi Jorg,<div><br></div><div>To be cle=
ar: There is no BC break with $_. Opcache doesn&#39;t discard variables con=
taining objects, so there is no observable change in behavior from what we&=
#39;re proposing. It doesn&#39;t change the variable semantics at all. Or a=
m I misunderstanding what you&#39;re referring to?</div><div><br></div><div=
>In addition, I reached out to see if Ond=C5=99ej (Creator of PHPStan) had =
an opinion: <a href=3D"https://phpc.social/@OndrejMirtes/114040888791921128=
">https://phpc.social/@OndrejMirtes/114040888791921128</a> - So on top of o=
ur previous arguments that PHP shouldn&#39;t depend on 3rd party tools for =
everything, there is also at least interest in having this in core from the=
 tool creators.</div><div><br></div><div>&gt; @edorian It already exists fo=
r PHPStan as a 3rd party extension: <a href=3D"https://github.com/DaveLidda=
ment/phpstan-php-language-extensions">https://github.com/DaveLiddament/phps=
tan-php-language-extensions</a> (MustUseResult)</div>&gt; Additionally, PHP=
Stan itself reports this if you call a @phpstan-pure method or function and=
 not use its result.<br>&gt;=C2=A0This attribute would be valuable for func=
tions that aren=E2=80=99t pure but you=E2=80=99re still supposed to read th=
e returned value.<div><br></div><div>Kind=C2=A0regards,</div><div>Volker</d=
iv><div><br></div></div><div class=3D"gmail_quote gmail_quote_container"><d=
iv dir=3D"ltr" class=3D"gmail_attr">--</div></div><div dir=3D"ltr" class=3D=
"gmail_signature"><div dir=3D"ltr"><div style=3D"color:rgb(34,34,34);font-f=
amily:arial,sans-serif;font-size:12.8px">Volker Dusch</div><div style=3D"co=
lor:rgb(34,34,34);font-family:arial,sans-serif;font-size:12.8px">Head of En=
gineering</div><div style=3D"color:rgb(34,34,34);font-family:arial,sans-ser=
if;font-size:12.8px"><div>Tideways GmbH</div><div>K=C3=B6nigswinterer Str. =
116</div><div>53227 Bonn</div><div><a href=3D"https://tideways.io/imprint" =
style=3D"color:rgb(17,85,204)" target=3D"_blank">https://tideways.io/imprin=
t</a><br></div><div><br></div><div>Sitz der Gesellschaft: Bonn</div><div>Ge=
sch=C3=A4ftsf=C3=BChrer: Benjamin Au=C3=9Fenhofer (geb. Eberlei)</div><div>=
Registergericht: Amtsgericht Bonn, HRB 22127</div></div></div></div></div>

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