Re: Deprecated partially supported callables: should is_callable() throw a deprecation notice ?

Am 16.03.2022 um 06:52 schrieb Juliette Reinders Folmer <php-internals_nospam@adviesenzo.nl>: > I've just been looking in detail at the Partially Supported Callables deprecation RFC: > https://wiki.php.net/rfc/deprecate_partially_supported_callables > > The RFC explicitly excludes the is_callable() function and the > callable type from throwing deprecation notices. > >> The |is_callable()| function and |callable| type remain side-effect free and do not throw a >> deprecation warning. They will continue to accept these callables until support is removed entirely. >> > > While I can fully support this for the callable type, I wonder > if the decision to not throw a deprecation on use in is_callable() > is the right one (though I understand the desire to keep it side-effect free). > > Consider these code samples: > > function foo(callable $callback) {} > foo('static::method'); > > This function call not throwing a deprecation is not problematic as in PHP 9.0 the function > will start throwing a TypeError. My reaction to your last sentence is actually quite the opposite: This is a major problem because code which was "just working" directly goes to a TypeError without a migration phase warning about it. This is something I've repeatedly advocated against. > if (is_callable('static::method')) { > static::method(); > } > > The second code sample, however, is problematic, as in PHP 9.0, the behaviour of this code will > be silently reversed for those callbacks which would previously result in > is_callable() returning true, which makes this a potentially > dangerous change without deprecation notice. I agree with you here: Code which silently changes behavior is also a migration hassle. - Chris