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Reply-To: bishop@php.net
Date: Tue, 25 Feb 2020 14:12:15 -0500
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To: Nikita Popov <nikita.ppv@gmail.com>
Cc: PHP internals <internals@lists.php.net>
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Subject: Re: [PHP-DEV] Deprecate ReflectionParameter::isArray() and friends
From: bishop@php.net (Bishop Bettini)

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On Tue, Feb 25, 2020 at 10:33 AM Nikita Popov <nikita.ppv@gmail.com> wrote:

> I've put up https://github.com/php/php-src/pull/5209 to deprecate the
> following reflection methods:
>
>  * ReflectionParameter::isArray()
>  * ReflectionParameter::isCallable()
>  * ReflectionParameter::getClass()
>
> These APIs have been superseded by ReflectionParameter::getType() since PHP
> 7.0. Types introduced since that time are not available through the old
> APIs. The behavior of these methods becomes increasingly confusing with
> additional type system extensions. With the addition of union types in PHP
> 8:
>
>  * isArray() will return true if the type is array or ?array, but not any
> other union type.
>  * getClass() will return a ReflectionClass for T|int etc, as long as the
> union only contains a single type. T1|T2 will return null.
>
> There is really no reasonable behavior for these methods in the presence of
> union types; we should start phasing them out.
>
> One point I'm not sure about is whether we want to deprecate
> ReflectionParameter::allowsNull() as well. Logically this method belongs on
> ReflectionType (and does in fact exist there), but the way it is formulated
> is still compatible with union types, so leaving it alone is a possibility.
>

Why do you say there's no "reasonable behavior ... in the presence of union
types"? To me, the following seem like reasonable interpretations in a
post-union-type world:

::isArray() returns true IIF is_array(type) === true for at least one type
in the parameter
::isCallable() returns true IIF is_callable(type) === true for at least one
type in the parameter
::getClass() returns null IIF class_exists(type) === false for all types in
the parameter; returns ReflectionClass IIF class_exists(type) for exactly
one type in the parameter; throws \TypeError otherwise

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