Re: Nullsafe
| From: | Eugene Sidelnyk | Date: | Wed, 04 Nov 2020 04:59:34 +0000 |
| Subject: | Re: Nullsafe | ||
| References: | 1 2 | Groups: | php.internals |
| Request: | Send a blank email to internals+get-112179@lists.php.net to get a copy of this message | ||
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.
>
>>