Everything

php

iterator_count signature for iterables

php.internals

[ ]

1 year ago

Hello internals!

Currently, iterator_count has the following signature:

iterator_count(Traversable|array $iterator): int

If we try to use iterable type and pass it to iterator_count function, we'd
get following static analysis error:

Argument 1 of iterator_count expects Traversable|array<array-key, mixed>,
but iterable<int, list<string>> provided (see https://psalm.dev/004)
$start(iterator_count($chunks));

From what I know, iterable is just built-in compile time type alias
for array|Traversable
(https://www.php.net/manual/en/language.types.iterable.php)

I think it would make sense to change the signature of iterator_count to
accept iterable rather than array|Traversable so that static analysis tools
would pick it up better

Tim Düsterhus

1 year ago

Hi

Am 2024-11-26 10:40, schrieb Eugene Sidelnyk:

> I think it would make sense to change the signature of iterator_count
> to
> accept iterable rather than array|Traversable so that static analysis
> tools
> would pick it up better

That sounds like a bug in Psalm's understanding of union types. PHPStan
handles it just fine:
https://phpstan.org/r/8604ef1d-3500-4695-8c23-bb5d30ce4268

Best regards
Tim Düsterhus

Marco Pivetta

1 year ago

Hey Tim,

On Tue, 26 Nov 2024 at 10:50, Tim Düsterhus <tim@bastelstu.be> wrote:

> Hi
>
> Am 2024-11-26 10:40, schrieb Eugene Sidelnyk:
> > I think it would make sense to change the signature of iterator_count
> > to
> > accept iterable rather than array|Traversable so that static analysis
> > tools
> > would pick it up better
>
> That sounds like a bug in Psalm's understanding of union types. PHPStan
> handles it just fine:
> https://phpstan.org/r/8604ef1d-3500-4695-8c23-bb5d30ce4268
>

Is `Traversable|array` an alias of `iterable`? Is it **always** like that?

Marco Pivetta

https://mastodon.social/@ocramius

https://ocramius.github.io/

Tim Düsterhus

1 year ago

Hi

Am 2024-11-26 12:00, schrieb Marco Pivetta:

> Is `Traversable|array` an alias of `iterable`? Is it **always** like
> that?

Since PHP 8.2 `iterable` is internally transformed into
`Traversable|array` on the engine level:
https://github.com/php/php-src/pull/7309. `iterable` no longer exists as
a type since then. But even before that it was *semantically* identical,
but technically it was a distinct type.

Best regards
Tim Düsterhus

Marco Pivetta

1 year ago

Hey Tim,

On Tue, 26 Nov 2024 at 12:07, Tim Düsterhus <tim@bastelstu.be> wrote:

> it was *semantically* identical,
>

That's the most important bit, thanks! That means that upstream Psalm may
translate back/forth from it into a uniform version :-)

To Eugene: consider posting this to the Psalm issue tracker.

Marco Pivetta

https://mastodon.social/@ocramius

https://ocramius.github.io/