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Subject: Re: [PHP-DEV] [RFC][Discussion] use construct (Block Scoping)
Date: Fri, 7 Nov 2025 20:36:15 +0100
In-Reply-To: <CAMW7n8Axo2jwrNq=owWUUVeu_nGZUNe5RMCUFd4qqXDKanL1=Q@mail.gmail.com>
Cc: Seifeddine Gmati <azjezz@carthage.software>,
 internals@lists.php.net
To: Edmond Dantes <edmond.ht@gmail.com>
References: <CAFyg4HhrzQrE-q8D6WVkyq9tY+hzR=8rXiXLDPYpNKdYeydrVA@mail.gmail.com>
 <CAMW7n8Bqze3Z7z9ZqSXSwVH4gqLQ3a9xYYSH33hvopOQ9DQChQ@mail.gmail.com>
 <CAFyg4HjvWDCtfcY8vMYekqpyoLVbXYed=ZMv2X+8UaE--p+QkA@mail.gmail.com>
 <CAMW7n8Dz+rbpi1HVhB=hJNevbraQrCqzvyQhev4MsL6NxqRJag@mail.gmail.com>
 <CAFyg4HgMQ4VrNgVZMdCsPh=hPm+E7EHNj88x3NKYGb9LXotLZA@mail.gmail.com>
 <CAMW7n8Axo2jwrNq=owWUUVeu_nGZUNe5RMCUFd4qqXDKanL1=Q@mail.gmail.com>
From: claude.pache@gmail.com (Claude Pache)


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> Le 6 nov. 2025 =C3=A0 06:01, Edmond Dantes <edmond.ht@gmail.com> a =
=C3=A9crit :
>=20
> Hello!
>=20
> ```php
> function addStudentLessons(DatabaseTransaction $transaction) {
>     try {
>          $transaction->execute(...);
>     } catch(\Exception $e) {
>         Logger::log($e);
>         throw $e;
>     }
> }
>=20
> // Application Code:
> function do_work(DatabasePool $pool): void {
>  using (
>    $connection =3D $pool->getConnection(),
>  ) {
>    using ($transaction =3D $connection->beingTransaction()) {
>      $transaction->execute('...');
>      sleep(10); // more work.
>      $transaction->execute('...');
>    }
>=20
>    sleep(10); // more work
>  }
>=20
>  sleep(10); // more work
> } // <=3D=3D broken!
> ```
>=20
> Logger::log($e); <=3D=3D reason!
>=20
> In this example, the `Logger` service holds the exception `$e`,
> which completely breaks the code because the transaction will no
> longer complete correctly, and it=E2=80=99s unclear when the resources =
will be
> released.
> This is even more true for stateful applications, where the Logger
> processes stored exceptions later rather than immediately.
>=20
> Note that I didn=E2=80=99t even use circular references. I=E2=80=99m =
sure that 90% of
> PHP developers who see this code won=E2=80=99t even understand what =
the
> problem is.
> And in practice, it will work for about 50% of them and fail for the =
other 50%.
>=20
> At the same time, as a programmer, I didn=E2=80=99t do anything =
particularly
> wrong or make any obvious mistake in this code. It=E2=80=99s just that =
the
> logging service holds the exception object for a while.
>=20
> RC-managed objects were designed to create code where the destruction
> time of an object cannot be determined statically (only at runtime).
> Automatic memory management is not a primary feature of RC objects,
> since it can be implemented without reference counting.
>=20
> However, the code in the example pursues the opposite goals: it must
> guarantee the exact moment a function is called. In other words, the
> RAII concept is not suitable here.
> And this situation is typical for PHP stateful applications, where
> resource control is not managed through RAII.
>=20
> ---
> Best Regards, Ed


Hi,

Indeed, and here is a proof (variation on the =E2=80=9CExample showing =
reliable resource management=E2=80=9D of the RFC):

https://3v4l.org/KJaL1

Something like a `Disposable` interface as suggested in the Future scope =
section, is probably the only way to make it reliable, and it ought to =
be part of the RFC.

=E2=80=94Claude



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<html><head><meta http-equiv=3D"content-type" content=3D"text/html; =
charset=3Dutf-8"></head><body style=3D"overflow-wrap: break-word; =
-webkit-nbsp-mode: space; line-break: after-white-space;"><br =
id=3D"lineBreakAtBeginningOfMessage"><div><br><blockquote =
type=3D"cite"><div>Le 6 nov. 2025 =C3=A0 06:01, Edmond Dantes =
&lt;edmond.ht@gmail.com&gt; a =C3=A9crit :</div><br =
class=3D"Apple-interchange-newline"><div><div>Hello!<br><br>```php<br>func=
tion addStudentLessons(DatabaseTransaction $transaction) {<br> =
&nbsp;&nbsp;&nbsp;&nbsp;try {<br> =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$transaction-&gt;exe=
cute(...);<br> &nbsp;&nbsp;&nbsp;&nbsp;} catch(\Exception $e) {<br> =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Logger::log($e);<br> =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;throw $e;<br> =
&nbsp;&nbsp;&nbsp;&nbsp;}<br>}<br><br>// Application Code:<br>function =
do_work(DatabasePool $pool): void {<br> &nbsp;using (<br> =
&nbsp;&nbsp;&nbsp;$connection =3D $pool-&gt;getConnection(),<br> &nbsp;) =
{<br> &nbsp;&nbsp;&nbsp;using ($transaction =3D =
$connection-&gt;beingTransaction()) {<br> =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$transaction-&gt;execute('...');<br> =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sleep(10); // more work.<br> =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$transaction-&gt;execute('...');<br> =
&nbsp;&nbsp;&nbsp;}<br><br> &nbsp;&nbsp;&nbsp;sleep(10); // more =
work<br> &nbsp;}<br><br> &nbsp;sleep(10); // more work<br>} // &lt;=3D=3D =
broken!<br>```<br><br>Logger::log($e); &lt;=3D=3D reason!<br><br>In this =
example, the `Logger` service holds the exception `$e`,<br>which =
completely breaks the code because the transaction will no<br>longer =
complete correctly, and it=E2=80=99s unclear when the resources will =
be<br>released.<br>This is even more true for stateful applications, =
where the Logger<br>processes stored exceptions later rather than =
immediately.<br><br>Note that I didn=E2=80=99t even use circular =
references. I=E2=80=99m sure that 90% of<br>PHP developers who see this =
code won=E2=80=99t even understand what the<br>problem is.<br>And in =
practice, it will work for about 50% of them and fail for the other =
50%.<br><br>At the same time, as a programmer, I didn=E2=80=99t do =
anything particularly<br>wrong or make any obvious mistake in this code. =
It=E2=80=99s just that the<br>logging service holds the exception object =
for a while.<br><br>RC-managed objects were designed to create code =
where the destruction<br>time of an object cannot be determined =
statically (only at runtime).<br>Automatic memory management is not a =
primary feature of RC objects,<br>since it can be implemented without =
reference counting.<br><br>However, the code in the example pursues the =
opposite goals: it must<br>guarantee the exact moment a function is =
called. In other words, the<br>RAII concept is not suitable here.<br>And =
this situation is typical for PHP stateful applications, =
where<br>resource control is not managed through =
RAII.<br><br>---<br>Best Regards, =
Ed<br></div></div></blockquote></div><br><div><br></div><div><div>Hi,</div=
><div><br></div><div>Indeed, and here is a proof (variation on the =
=E2=80=9CExample showing reliable resource management=E2=80=9D of the =
RFC):</div><div><br></div><div><a =
href=3D"https://3v4l.org/KJaL1">https://3v4l.org/KJaL1</a></div><div><br><=
/div><div>Something like a `Disposable` interface as suggested in the =
Future scope section, is probably the only way to make it reliable, and =
it ought to be part of the =
RFC.</div><div><br></div><div>=E2=80=94Claude</div><div><br></div><br =
class=3D"Apple-interchange-newline"></div></body></html>=

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