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References: <CAM0CcxjF3TzcFZegM3KvA07K_dQPnN=Mp-kkYK94Mja487KKtQ@mail.gmail.com>
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In-Reply-To: <CADyq6sJefdWYh=sKMgWDnKG48as4KpSKUEQU2+_Oa5KM0Kf6kA@mail.gmail.com>
Date: Wed, 4 Nov 2020 06:59:34 +0200
Message-ID: <CAM0CcxgFbF8a11jy572Gnm=aWJNe0=hsHV6CHNgm8A2DQEM05w@mail.gmail.com>
To: Marco Pivetta <ocramius@gmail.com>
Cc: PHP Internals List <internals@lists.php.net>
Content-Type: multipart/alternative; boundary="0000000000002491a105b340d963"
Subject: Re: [PHP-DEV] Nullsafe
From: zsidelnik@gmail.com (Eugene Sidelnyk)

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But wait!

In your example, funds won't get detracted. If `$accounts->get($receiver)`
will return `null`, then everything inside `addFunds(...)` will not be
executed.
Your example (simplified): https://3v4l.org/38Dk3

Another one:
```php
function expensive_function() {
    var_dump(__FUNCTION__);
}

$foo = null;

$foo?->baz(expensive_function());
```

On Tue, Nov 3, 2020 at 10:11 PM Marco Pivetta <ocramius@gmail.com> wrote:

> Heya,
>
> On Tue, Nov 3, 2020, 17:38 Eugene Sidelnyk <zsidelnik@gmail.com> wrote:
>
>> Hello, internals!
>> I am wondering why don't we use ordinary `->` operator with safe null
>> handling? Programmers will be more prone to return null values. And thus,
>> in most of cases `?->` will replace `->`.
>> Why do we need another operator, if we can implement null safe in current
>> operator without BC breaks?
>>
>
> Overall, "null safe" can be very dangerous if made the default.
>
> Here's a scenario where I'd never want "null safe" behaviour (which does
> anything but introducing safety):
>
> ```php
> $accounts->get($receiver)
>     ->addFunds(
>         $accounts->get($sender)
>             ->detractFunds($amount)
>     );
> ```
>
> In the above scenario, if the first `$accounts->get()` call returns `null`
> for any reason, you may actually destroy money (funds detracted, but never
> added to another account).
>
> The example is simplistic, but it shows that "null safe" is everything but
> "safe", and it must instead be used only where it absolutely makes sense to
> suppress null reference errors.
>
> Similar behaviour can be observed around cast operators, which are too lax
> for most businesses logic:
> https://github.com/ShittySoft/symfony-live-berlin-2018-doctrine-tutorial/pull/3#issuecomment-460441229
>
> Safe = crashes when it should crash.
>
>>

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