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Date: Thu, 27 May 2021 11:33:09 -0400
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To: Rowan Tommins <rowan.collins@gmail.com>
Subject: Re: [PHP-DEV] Consensus Gathering: is_initialized
From: mike@newclarity.net (Mike Schinkel)

> On May 27, 2021, at 10:43 AM, Rowan Tommins <rowan.collins@gmail.com> =
wrote:
>=20
> On 27/05/2021 14:55, Andreas Leathley wrote:
>>=20
>> When using isset on a non-nullable property a
>> static analyzer would rightfully complain that the property is not
>> nullable
>=20
>=20
> Precisely, so don't mark a property as non-nullable and then leave it =
unset.
>=20
>=20
>> isset in this case is abused to check for uninitialized, hiding the
>> actual intent
>=20
>=20
> On the contrary, the uninitialized state is what is being abused. If =
you want to make the intent clear, use a clear flag of "needs =
lazy-loading", or whatever you're actually using this magic "not null =
but not really anything else either" state for.

If in fact that uninitialized state is "being abused" as asserted, maybe =
the real abuse is the fact that PHP allows such a state to exist in the =
first place?

Since the argument against is_initialized() seems to almost universally =
be that we should not write code that lets type properties be =
uninitialized past the constructor then it would follow that PHP is in =
the wrong to even allow uninitialized state past the constructor?=20

If a property is defined as `?int` or `null|int` why should PHP allow an =
uninitialized state to begin with?  Why shouldn't PHP initialize any of =
those properties to null to begin with? =20

And for non-nullable, why shouldn't PHP default `int` to 0, `string` to =
`""`, `array` to `[]`, etc.?

But if the answer is that PHP *should* have an uninitialized state past =
the constructor then it makes good sense to have a *performant* =
is_initialized() function to allow userland to discern the difference =
when applicable use-cases occur.

Maybe the proper solution would be for PHP to set a default value to any =
uninitialized properties at the end of the constructor, null for =
properties that are nullable or objects, and a known default for any =
scalar types?  Then post-constructor it would not be possible to have =
uninitialized and thus no need for the function?

-Mike