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Date: Sun, 29 Oct 2023 11:35:37 +0000
In-Reply-To: <CAGBsUrd1XKemzoGO22_+wUQqJY2JQU=vVXndmo8zRjEZxJtYcQ@mail.gmail.com>
Cc: PHP internals <internals@lists.php.net>
To: Kamil Tekiela <tekiela246@gmail.com>
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 <CAGBsUrd1XKemzoGO22_+wUQqJY2JQU=vVXndmo8zRjEZxJtYcQ@mail.gmail.com>
Subject: Re: [PHP-DEV] Passing null to parameter
From: craig@craigfrancis.co.uk (Craig Francis)

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On 29 Oct 2023, at 11:14, Kamil Tekiela <tekiela246@gmail.com> wrote:
> A code like this already throws a fatal error.
>=20
> function enc(string $a){}
> enc(null);
>=20
> The only thing remaining to be fixed in PHP 9 is to make this error =
consistent on all function invocations.



Or, be consistent with all of the other type coercions?


```
function user_function(string $s, int $i, float $f, bool $b) {
  var_dump($s, $i, $f, $b);
}
=20
user_function('1', '1', '1', '1');
  // string(1) "1" / int(1) / float(1) / bool(true)
=20
user_function(2, 2, 2, 2);
  // string(1) "2" / int(2) / float(2) / bool(true)
=20
user_function(3.3, 3.3, 3.3, 3.3);
  // string(3) "3.3" / int(3), lost precision / float(3.3) / bool(true)
=20
user_function(false, false, false, false);
  // string(0) "" / int(0) / float(0) / bool(false)
```


The documentation does clearly say how NULL should be coerced:

https://www.php.net/manual/en/language.types.string.php
"null is always converted to an empty string."

https://www.php.net/manual/en/language.types.integer.php
"null is always converted to zero (0)."

https://www.php.net/manual/en/language.types.float.php
"For values of other types, the conversion is performed by converting =
the value to int first and then to float"

https://www.php.net/manual/en/language.types.boolean.php
"When converting to bool, the following values are considered false =
[...] the special type NULL"


Maybe documentation should be amended to say "except when being passed =
to a function"?

Or, should we have fatal errors with the following as well:

```
$nullable =3D NULL;

print($nullable);

echo $nullable;

printf('%s', $nullable);

var_dump('A' . $nullable);

var_dump(3 + $nullable);

var_dump($nullable / 6);

var_dump('' =3D=3D $nullable);
```



> Without it, you would never know that you have a logical error in your =
code.


But it's not an error?

Craig


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