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Date: Thu, 8 Jul 2021 18:50:20 +0900
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To: PHP internals <internals@lists.php.net>
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Subject: Re: [RFC] Add Random Extension (before: Add Random class)
From: zeriyoshi@gmail.com (Go Kudo)

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Hello Internals.

I mistakenly thought there was still time, but voting for a new RFC for PHP
8.1 has already closed.

I believe that an object-scoped random number generator is a necessity for
PHP and I will continue to work on it. We will continue to improve the RFC.

I will also work on getting it published in PECL so that features are
available quickly.

Regards,
Go Kudo

2021=E5=B9=B46=E6=9C=8826=E6=97=A5(=E5=9C=9F) 9:39 Go Kudo <zeriyoshi@gmail=
.com>:

> Hello Internals.
>
> RFC has been reorganized for finalization.
>
> https://wiki.php.net/rfc/rng_extension
>
> The changes from the previous version are as follows:
>
> - Changed again to a class-based approach. The argument can be omitted, i=
n
> which case an instance of XorShift128Plus will be created automatically.
> - Future scope was specified in the RFC and the functionality was
> separated as a Random extension.
> - Changed to separate it as a Random extension and use the appropriate
> namespace.
> - In order to extend the versatility of the final class, Random, a
> RandomInterface has been added, similar in approach to the
> DateTimeInterface.
>
> I've done a tidy implementation to make this final, but I'm currently
> suffering from error detection by Valgrind for unknown reasons.
>
> Implementation is here: https://github.com/php/php-src/pull/7079
>
> This can be reproduced with the following code.
>
> ```sh
> # Success
> $ valgrind ./sapi/cli/php -r '$random =3D new Random(); $random->nextInt(=
);'
> =3D=3D95522=3D=3D Memcheck, a memory error detector
> =3D=3D95522=3D=3D Copyright (C) 2002-2017, and GNU GPL'd, by Julian Sewar=
d et al.
> =3D=3D95522=3D=3D Using Valgrind-3.14.0 and LibVEX; rerun with -h for cop=
yright
> info
> =3D=3D95522=3D=3D Command: ./sapi/cli/php -r $random\ =3D\ new\ Random();=
\
> $random-\>nextInt();
> =3D=3D95522=3D=3D
> =3D=3D95522=3D=3D
> =3D=3D95522=3D=3D HEAP SUMMARY:
> =3D=3D95522=3D=3D     in use at exit: 1,286 bytes in 32 blocks
> =3D=3D95522=3D=3D   total heap usage: 28,445 allocs, 28,413 frees, 4,333,=
047 bytes
> allocated
> =3D=3D95522=3D=3D
> =3D=3D95522=3D=3D LEAK SUMMARY:
> =3D=3D95522=3D=3D    definitely lost: 0 bytes in 0 blocks
> =3D=3D95522=3D=3D    indirectly lost: 0 bytes in 0 blocks
> =3D=3D95522=3D=3D      possibly lost: 0 bytes in 0 blocks
> =3D=3D95522=3D=3D    still reachable: 1,286 bytes in 32 blocks
> =3D=3D95522=3D=3D         suppressed: 0 bytes in 0 blocks
> =3D=3D95522=3D=3D Rerun with --leak-check=3Dfull to see details of leaked=
 memory
> =3D=3D95522=3D=3D
> =3D=3D95522=3D=3D For counts of detected and suppressed errors, rerun wit=
h: -v
> =3D=3D95522=3D=3D ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 =
from 0)
>
> # Fail
> $ valgrind ./sapi/cli/php -r '$random =3D new Random(); $random->nextInt(=
)
> =3D=3D=3D $random->nextInt();'
> =3D=3D95395=3D=3D Memcheck, a memory error detector
> =3D=3D95395=3D=3D Copyright (C) 2002-2017, and GNU GPL'd, by Julian Sewar=
d et al.
> =3D=3D95395=3D=3D Using Valgrind-3.14.0 and LibVEX; rerun with -h for cop=
yright
> info
> =3D=3D95395=3D=3D Command: ./sapi/cli/php -r $random\ =3D\ new\ Random();=
\
> $random-\>nextInt()\ =3D=3D=3D\ $random-\>nextInt();
> =3D=3D95395=3D=3D
> =3D=3D95395=3D=3D Conditional jump or move depends on uninitialised value=
(s)
> =3D=3D95395=3D=3D    at 0x966925: ZEND_IS_IDENTICAL_SPEC_VAR_VAR_HANDLER
> (zend_vm_execute.h:27024)
> =3D=3D95395=3D=3D    by 0x99AC27: execute_ex (zend_vm_execute.h:57236)
> =3D=3D95395=3D=3D    by 0x99C902: zend_execute (zend_vm_execute.h:59026)
> =3D=3D95395=3D=3D    by 0x8DB6B4: zend_eval_stringl (zend_execute_API.c:1=
191)
> =3D=3D95395=3D=3D    by 0x8DB861: zend_eval_stringl_ex (zend_execute_API.=
c:1233)
> =3D=3D95395=3D=3D    by 0x8DB8D6: zend_eval_string_ex (zend_execute_API.c=
:1243)
> =3D=3D95395=3D=3D    by 0xA4DAE4: do_cli (php_cli.c:995)
> =3D=3D95395=3D=3D    by 0xA4E8E2: main (php_cli.c:1366)
> =3D=3D95395=3D=3D
> =3D=3D95395=3D=3D
> =3D=3D95395=3D=3D HEAP SUMMARY:
> =3D=3D95395=3D=3D     in use at exit: 1,286 bytes in 32 blocks
> =3D=3D95395=3D=3D   total heap usage: 28,445 allocs, 28,413 frees, 4,333,=
070 bytes
> allocated
> =3D=3D95395=3D=3D
> =3D=3D95395=3D=3D LEAK SUMMARY:
> =3D=3D95395=3D=3D    definitely lost: 0 bytes in 0 blocks
> =3D=3D95395=3D=3D    indirectly lost: 0 bytes in 0 blocks
> =3D=3D95395=3D=3D      possibly lost: 0 bytes in 0 blocks
> =3D=3D95395=3D=3D    still reachable: 1,286 bytes in 32 blocks
> =3D=3D95395=3D=3D         suppressed: 0 bytes in 0 blocks
> =3D=3D95395=3D=3D Rerun with --leak-check=3Dfull to see details of leaked=
 memory
> =3D=3D95395=3D=3D
> =3D=3D95395=3D=3D For counts of detected and suppressed errors, rerun wit=
h: -v
> =3D=3D95395=3D=3D Use --track-origins=3Dyes to see where uninitialised va=
lues come
> from
> =3D=3D95395=3D=3D ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 =
from 0)
> ```
>
> However, the detection is internal to the Zend VM and the cause has not
> been identified. From the code, it looks like memory management is being
> done properly.
>
> I have a somewhat tricky way of allocating memory to make the process
> common, do I need to give some hints to Valgrind?
>
> If you know, I would appreciate your advice on this issue.
>
> Regards,
> Go Kudo
>

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