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Date: Wed, 2 Jul 2025 00:56:39 +0900
Message-ID: <CAHR_AjQPpzESTrgtZJqNq_pHwow5Y3Hoa6gEzMadZhijhy7Sdw@mail.gmail.com>
Subject: Re: [PHP-DEV] Expanding the scope of the #[NoDiscard] attribute
To: =?UTF-8?Q?Tim_D=C3=BCsterhus?= <tim@bastelstu.be>
Cc: internals@lists.php.net
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From: tadsan@zonu.me (Kenta Usami)

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Hi Tim,

Thank you for your reply and for the clarification.
As one of the RFC authors, your insight is very helpful.

I now have a much clearer understanding of the RFC's intent. Your
point that #[NoDiscard] is not meant for every pure function, but
rather for those where ignoring the return value leads to dangerous,
hard-to-detect bugs, makes perfect sense. I agree that focusing the
runtime check on high-risk functions, while leaving most pure
functions to static analysis, is a reasonable approach.

Based on that criterion, I understand that very few built-in functions
should be marked with #[NoDiscard].

To give some context, my initial proposal was motivated by the ongoing
confusion around the semantics of the #[Pure] attribute in the
JetBrains stubs for static analysis. I had hoped that marking more
built-in functions with #[NoDiscard] could help clarify the situation,
but I now see that this is not the appropriate goal for this
attribute.
https://github.com/JetBrains/phpstorm-stubs/pull/1730

It seems a different approach is needed to solve that particular
problem for static analyzers.

Thanks again for your time and the explanation.

Best regards,
Kenta

--=20
=E3=83=BE(=E3=80=83=EF=BC=9E=EF=BC=9C)=EF=BE=89=EF=BE=9E=E2=98=86 Kenta Usa=
mi (=E5=AE=87=E4=BD=90=E7=BE=8E=E5=81=A5=E5=A4=AA)
github.com/zonuexe ; https://tadsan.github.io/

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<div dir=3D"ltr"><div dir=3D"ltr">Hi Tim,<br><br>Thank you for your reply a=
nd for the clarification.<br>As one of the RFC authors, your insight is ver=
y helpful.<br><br>I now have a much clearer understanding of the RFC&#39;s =
intent. Your<br>point that #[NoDiscard] is not meant for every pure functio=
n, but<br>rather for those where ignoring the return value leads to dangero=
us,<br>hard-to-detect bugs, makes perfect sense. I agree that focusing the<=
br>runtime check on high-risk functions, while leaving most pure<br>functio=
ns to static analysis, is a reasonable approach.<br><br>Based on that crite=
rion, I understand that very few built-in functions<br>should be marked wit=
h #[NoDiscard].<br><br>To give some context, my initial proposal was motiva=
ted by the ongoing<br>confusion around the semantics of the #[Pure] attribu=
te in the<br>JetBrains stubs for static analysis. I had hoped that marking =
more<br>built-in functions with #[NoDiscard] could help clarify the situati=
on,<br>but I now see that this is not the appropriate goal for this<br>attr=
ibute.<br><a href=3D"https://github.com/JetBrains/phpstorm-stubs/pull/1730"=
>https://github.com/JetBrains/phpstorm-stubs/pull/1730</a><br><br>It seems =
a different approach is needed to solve that particular<br>problem for stat=
ic analyzers.<br><br>Thanks again for your time and the explanation.<br><br=
>Best regards,<br>Kenta</div></div><div><br></div><span class=3D"gmail_sign=
ature_prefix">-- </span><br><div dir=3D"ltr" class=3D"gmail_signature"><div=
 dir=3D"ltr">=E3=83=BE(=E3=80=83=EF=BC=9E=EF=BC=9C)=EF=BE=89=EF=BE=9E=E2=98=
=86 Kenta Usami (<font face=3D"ms pmincho, serif">=E5=AE=87=E4=BD=90=E7=BE=
=8E=E5=81=A5=E5=A4=AA</font>)<br><div><a href=3D"http://github.com/zonuexe"=
 target=3D"_blank">github.com/zonuexe</a> ; <a href=3D"https://tadsan.githu=
b.io/" target=3D"_blank">https://tadsan.github.io/</a></div></div></div>

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