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Date: Mon, 19 Jun 2017 17:16:02 +0200
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To: Sammy Kaye Powers <me@sammyk.me>
Cc: PHP Internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] [RFC] [Discussion] Retry functionality
From: ocramius@gmail.com (Marco Pivetta)

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Content-Type: text/plain; charset="UTF-8"

Hey Sammy,

From a language design perspective, this is syntactic sugar that brings a
lot of cost for anyone working on optimisations.

In most scenarios that I worked on, the retry functionality should always
be written as following:


try {
    $externalCollaborator->doSomething($with, $a, $lot, $of, $by, $val,
$parameters);
} catch (SomethingSomething $e) {
    $externalCollaborator->doSomething($with, $a, $lot, $of, $by, $val,
$parameters);
}

The reason why it is extremely important to have an external collaborator
is that logic wrapped in a retry *MUST* be tested for idempotence.
Just imagine what could happen if a credit card payment was processed twice!

That said, the above can be rewritten as following:

retry(
    function () use ($externalCollaborator, $with, $a, $lot, $of, $by,
$val, $parameters) {
        $externalCollaborator->doSomething($with, $a, $lot, $of, $by, $val,
$parameters);
    },
    [SomethingSomething::class],
    1
);

Where the signature of `retry` is as following:

function retry(callable $executedLogic, array $caughtExceptionTypes, int
$maxRetries) { /* ... */ }

This kind of approach is simpler to understand, to test, and doesn't
include the "hidden GOTO semantics" that are proposed in this patch, and
that would make SSA optimizations quite hard to perform.

Given the above, I'm sadly going to vote "NO" on this proposal.

Greets,




Marco Pivetta

http://twitter.com/Ocramius

http://ocramius.github.com/

On Mon, Jun 19, 2017 at 3:55 PM, Sammy Kaye Powers <me@sammyk.me> wrote:

> Hello internals!
>
> The RFC that proposes adding retry functionality to the
> `try/catch/finally` block is now officially "under discussion".
>
> https://wiki.php.net/rfc/retry-keyword
>
> Voting will open on Monday, July 3rd, 2017 @ 9 am CDT.
>
> Voting will close on Monday, July 17th, 2017 @ 9 am CDT.
>
> Discuss amongst yourselves. :)
>
> Thanks,
> Sammy Kaye Powers
> sammyk.me
>
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>

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