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Nullsafe array access can still emit a warning

php.internals

Gert

4 years ago

Hi Internals,

I recently learned that using null safe on an array access can still
emit a warning when the array access is not defined. I kinda expected
it to work like a null coalesce and just short circuit there,without
the warning.

Is there any chance this behaviour could be changed in a n upcoming
PHP version? I didn't see anything mentioned specifically about this
in the RFC.

https://3v4l.org/1raa8

Greetings,
Gert de Pagter/ BackEndTea

Marco Pivetta

4 years ago

Hey Gert,

On Wed, 24 Aug 2022 at 14:59, Gert de Pagter <gertp93@gmail.com> wrote:

> Hi Internals,
>
> I recently learned that using null safe on an array access can still
> emit a warning when the array access is not defined. I kinda expected
> it to work like a null coalesce and just short circuit there,without
> the warning.
>
> Is there any chance this behaviour could be changed in a n upcoming
> PHP version? I didn't see anything mentioned specifically about this
> in the RFC.
>
> https://3v4l.org/1raa8
>
> Greetings,
> Gert de Pagter/ BackEndTea
>

This seems expected behavior to me: it's "nullsafe", not "undefinedsafe".

If it operated like `??`, then `$undefined?->bar()` would be valid too,
which seems wrong, IMO.

Marco Pivetta

https://twitter.com/Ocramius

https://ocramius.github.io/

Gert

4 years ago

`$undefined?->bar()` does feel wrong, but `$arr[0]?->bar()` does not to me.

But maybe i've just been using javascript too much lately

On Wed, 24 Aug 2022 at 15:11, Marco Pivetta <ocramius@gmail.com> wrote:

[ ]

4 years ago

I completely agree with Marco. We should not mix up nullsafe operator with
array access. As for me, aforementioned code works as expected.

As an improvement, we can think of access-safe operator (like `$arr[?0]`),
however I'm not sure if introduction of such will make sense.

Regards
Yevhen

On Wed, Aug 24, 2022, 4:11 PM Marco Pivetta <ocramius@gmail.com> wrote:

Christoph Becker

4 years ago

On 24.08.2022 at 14:58, Gert de Pagter wrote:

> I recently learned that using null safe on an array access can still
> emit a warning when the array access is not defined. I kinda expected
> it to work like a null coalesce and just short circuit there,without
> the warning.
>
> Is there any chance this behaviour could be changed in a n upcoming
> PHP version? I didn't see anything mentioned specifically about this
> in the RFC.
>
> https://3v4l.org/1raa8

That behaves as documented[1]:

| The nullsafe operator works the same as property or method access as
| above, except that if the object being dereferenced is null then null
| will be returned rather than an exception thrown.

And particularly:

| The effect is similar to wrapping each access in an is_null() check
| first, but more compact.

However, see e.g.
<https://github.com/php/php-src/issues/7825#issuecomment-1100052164>.

[1]
<https://www.php.net/manual/en/language.oop5.basic.php#language.oop5.basic.nullsafe>

--
Christoph M. Becker