[RFC][Discussion] Consistent callables

Hi,

I'd like to introduce an RFC to cleanup the behaviour of callables and
related functions in PHP.

https://wiki.php.net/rfc/consistent_callables

Note, this RFC targets PHP 8, with soft deprecations in PHP 7.3 and
deprecation notices in 7.last. This means there is a lot of time for
reading and thinking about the RFC.

One piece of feedback I've had from informal discussions is that the
BC break for one part is too big even for a major release number. I'd
like to get other people's opinion on the RFC before possibly
modifying it.

Additionally modifying the signature of is_callable() might not be the
best path. Again, looking forward to getting the opinion of other
people.

cheers
Dan
Ack

--

Hi Dan,

While there is a difference, your resulting comments are reversed for the "call_user_func different from is_callable” section. The call_user_func invocation works properly, the direct invocation does not.

A lot of the things you’re highlighting as “errors” or “is_callable lied to us” are neither - they’re just a consequence of scope, and I think the wording should be changed, because “it lied” has very different meaning to “it’s response is not necessary applicable in a different scope”. If an astronaut on the moon says he weighs 11.5kg, but you are looking at his medical report on Earth and it says he weighs 69kg, would you call him a liar?

Regarding the big change you suggest, making protected/private methods return false unless a new third parameter is true in is_callable():

I think you need to make your intention a lot clearer under the "Private and protected functions no longer report as callable for is_callable” section. You make no mention of it being user controlled, simply “this will not work any more”, until the next section.

As for the actual change: I think for the sake of BC, and frankly logic, it would make more sense, to reverse your flag, so the default respects current behaviour, but it gives people who rely on is_callable() from another scope the ability to make sure they only get universally-callable values.

Lastly - you mention the need to use Reflection to create closures, but Closure::fromCallable exists, so perhaps you drafted this before that passed, and haven’t updated that part?

Cheers,

Stephen

Hi,

I'd like to introduce an RFC to cleanup the behaviour of callables and
related functions in PHP.

https://wiki.php.net/rfc/consistent_callables

Hi Dan,

I like the principle behind this RFC, so thanks for tackling it. A few comments came to mind from a first read through:

In your strict definition of a callable, you mention "a string at index 0 which is a valid class name"; this should probably say "a fully qualified class name", i.e. Foo:: class not 'Foo'. This would fit with your proposal to remove support for 'self' and 'static', as the meaning of 'Foo' depends on the current namespace and aliases.

Regarding is_callable, I appreciate you want to keep the parameter list short, but I think replacing an existing parameter without any version where it's removed completely could lead to some very confusing bugs. IMO, when BC breaks are necessary, they should be big and obvious so people spot and fix them.

Finally, I notice you target a few deprecations at "7.last"; the problem with that is that we might not know when we release that version that it will be the last. It wasn't decided until nearly a year after 5.6 was released that there wouldn't be a 5.7, and the idea of creating a 5.7 containing only deprecations was ruled out. Suggestions to plot a roadmap of future releases have so far but gained traction, so it's likely that 8.0 will be a similar scenario.

Regards,

--
Rowan Collins
[IMSoP]