Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:120969
Content-Type: multipart/alternative;
 boundary="------------FUntaCn7Gg9YFJKuuT4bzONs"
Message-ID: <5075145d-dcbc-a993-9394-665fbb6fd747@gmail.com>
Date: Fri, 1 Sep 2023 19:09:11 +0100
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101
 Thunderbird/102.15.0
To: internals@lists.php.net
References: <4406C50C-18FF-4F20-BA7B-206E86610CCC@sakiot.com>
Content-Language: en-GB
In-Reply-To: <4406C50C-18FF-4F20-BA7B-206E86610CCC@sakiot.com>
Subject: Re: [PHP-DEV] Apply strict_types to internal functions
From: rowan.collins@gmail.com (Rowan Tommins)

--------------FUntaCn7Gg9YFJKuuT4bzONs
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit

On 29/08/2023 01:46, Saki Takamachi wrote:
> As the documentation below states, PHP's internal functions currently ignore strict_types.
> https://www.php.net/manual/en/language.types.declarations.php#language.types.declarations.strict


Just to be really clear, it is not true that internal functions "ignore" 
the setting; they behave exactly the same as any userland function which 
was *declared* in strict_types=0 mode.

The warning in the manual is actually a consequence of the following 
Note (perhaps the order should be reversed?):

1. Strict typing applies to function calls made from within the file 
with strict typing enabled
2. Function calls from within internal functions will not be affected by 
the |strict_types| declaration


To clarify the scenario, imagine three files:

/* a.php */
declare(strict_types=0);
function call_me_back(callable $f, mixed $input) {
     $f($input);
}

/* b.php */
declare(strict_types=1);
function output_me(string $output) {
     echo "$output\n";
}

/* c.php */
declare(strict_types=1);
call_me_back( output_me(...), 42 );

The only calls that happen are:

1. A call from c.php to call_me_back; c.php is in strict_types=1 mode, 
so the parameters $f and $input will not be coerced
2. A call from a.php to output_me; a.php is in strict_types=0 mode, so 
the parameter $output *will* be coerced to a string


The behaviour of internal functions like array_filter is exactly the 
same - array_filter is  the caller, and it is defined in strict_types=0 
mode, just like call_me_back above; the mode set in any other code is 
irrelevant, because it is not the caller.


As Claude Pache, it's actually very difficult to design a version of the 
feature that would be fully intuitive in this case - if I write the 
below, does the caller of wrapped_array_filter still get to control the 
mode that call_me_back is run under?

function call_me_back(int $value) {
     return $value <= 42;
}
function backwards_array_filter(array $array, ?callable $callback = 
null, int $mode = 0): array {
     return array_reverse(   array_filter($array, $callback, $mode)   );
}
// In another file:
var_dump( backwards_array_filter($some_array, call_me_back(...)) );


Regards,

-- 
Rowan Tommins
[IMSoP]

--------------FUntaCn7Gg9YFJKuuT4bzONs--