Re: Canonicalize "iterable" into "array|Traversable" and Reflection

On Sat, Apr 23, 2022, at 7:27 AM, G. P. B. wrote: > Hello internals, > > One area the engine currently needs to take special care is dealing with > the typing relation between iterable, Traversable, and array. > The change is to canonicalize "iterable" into "array|Traversable" as this > then removes this special case. > > However, doing so breaks Reflection for iterable types and will now return > a ReflectionUnionType instead of a ReflectionNamed type. > There are a couple of options to proceed: > - Accept the BC break, and expect end users to already be handling union > types for code running on 8.2 (least complexity) > - Only provide a BC layer for (?)iterable to return a ReflectionNamedType > and have usages of iterable in a union type be exposed as Traversable|array > (OK complexity) > - Full BC such that even in union types where iterabl was used > Traversable|array gets converted back to iterable (high complexity) > > The PR for this change is > https://github.com/php/php-src/pull/7309 > > This PR is also blocking the implementation for DNF types, as it vastly > simplifies the implementation of it. > > Best regards, > > George P. Banyard To make sure I understand, Option 1: * function foo(iterable $i) // $i is ReflectionUnionType of array,traversable * function foo(iterable|Beep $i) // $i is ReflectionUnionType of array,Traversable,Beep Option 2: * function foo(iterable $i) // $i is ReflectionNamedType of iterable * function foo(iterable|Beep $i) // $i is ReflectionUnionType of array,Traversable,Beep Option 3: * function foo(iterable $i) // $i is ReflectionNamedType of iterable * function foo(iterable|Beep $i) // $i is ReflectionUnionType of iterable,Beep Am I following correctly? If so, I'm fine with 1 or 2. I... cannot imagine a situation where someone is doing iterable|Beep to begin with, so I don't really care if that is a slight break. Though... I do have some code that might get cranky with Option 1, as it doesn't deal with union types at all (for various reasons). I don't think it currently deals with iterables either, which is possibly an oversight... So, I think my preference would be 2, 1, no 3. --Larry Garfield