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Date: Thu, 1 Apr 2021 15:56:04 +0200
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Subject: Re: [PHP-DEV] [VOTE] noreturn type
From: a.leathley@gmx.net (Andreas Leathley)

On 01.04.21 10:56, Benjamin Eberlei wrote:
> This RFC is using the declaration of the return type, to specify that it
> never returns. As such noreturn or never is a keyword a long the lines o=
f
> public or final, but it is not a return type.
>
> I don't think the argument for potential optimizations in Opcache to
> eliminate dead code or allow IDEs to hint at dead code are valuable enou=
gh
> to justify this change.

I already use @return no-return (supported by Psalm/PHPStan) in my code
now, to clarify the code flow, and for me it fits perfectly for return
types, as not returning is also a result of the function/method. Having
a return type of "int" or "string" (or even "void") seems misleading
when the method will never return anyway.

noreturn/never might not be useful in all code, but for some parts like
in a controller of a web application it makes handling redirects,
authorization or 404 errors much easier, clearer and less error-prone,
for example:

```php
if (!isset($user)) {
 =C2=A0 $this->notFound(); // this is a noreturn/never method
}

if (!$this->isGranted('adminPrivileges')) {
 =C2=A0 $this->notAuthorized(); // this is a noreturn/never method
}
```

Adding noreturn/never on a language level would make sure calling
"$this->notAuthorized();" never continues code flow. This is often also
a security issue, as seen by an alternative way of handling the above
use cases:

```php
if (!isset($user)) {
 =C2=A0 $this->notFound();
 =C2=A0 return;
}

if (!$this->isGranted('adminPrivileges')) {
 =C2=A0 $this->notAuthorized();
 =C2=A0 return;
}
```

If you forget a return, suddenly you have issues. So even though
noreturn/never is a niche language feature not everyone will use, it
does address a very real use case. Using attributes has the disadvantage
of not making the intent clear:

```php
#[\NoReturn]
function notAuthorized(): string
{
 =C2=A0 // Some code
}
```

Now you have a return type of string, but also the information that the
function will never return anyway. That is confusing, but will be
inevitable in some cases when implementing interfaces or an abstract
class. In my opinion, the string return type is wrong in this case and
can only mislead a developer.