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Date: Tue, 3 Nov 2020 20:56:33 +0100
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To: Eugene Sidelnyk <zsidelnik@gmail.com>
Subject: Re: [PHP-DEV] Nullsafe
From: claude.pache@gmail.com (Claude Pache)



> Le 3 nov. 2020 =C3=A0 17:38, Eugene Sidelnyk <zsidelnik@gmail.com> a =
=C3=A9crit :
>=20
> Hello, internals!
> I am wondering why don't we use ordinary `->` operator with safe null
> handling? Programmers will be more prone to return null values. And =
thus,
> in most of cases `?->` will replace `->`.
> Why do we need another operator, if we can implement null safe in =
current
> operator without BC breaks?

Hi,

In a parallel world where people never commit bugs, yes, this is =
reasonable semantics.

However, it happens more than once that a null value occurs by accident =
where an object is expected by the programmer. In this case, I very much =
prefer to have a Warning or an Error, typically handled by an error =
handler which sends a bug report to the developer, then triggers an =
emergency stop. That makes it much easier to locate and fix bugs.

Of course, this debuggability facility have to be balanced with the =
inconvenience to having to write more code in cases where a null value =
is expected. Having to write =E2=80=9C?->=E2=80=9D instead of =E2=80=9C->=E2=
=80=9D in those cases is a minimal inconvenience. Here, I mean =
=E2=80=9Cminimal=E2=80=9D in a very literal way: exactly one character =
of difference.

Also, there is the following benefit: When I write =E2=80=9C->=E2=80=9D, =
I am stating that the LHS value should never be null; when I write =
=E2=80=9C?->=E2=80=9D, I am stating that I expect that the LHS is =
sometimes null. Thus, my code is documented in a very concise way =
(between zero and one character), which is an aid for any future reader =
(including myself).

Aside: The name =E2=80=9Cnullsafe=E2=80=9D is misleading. The operator =
is not about safety, it is about handling null values in a concise way. =
In fact, in some circumstances, sweeping an unexpected null value under =
the rug may be totally unsafe.

=E2=80=94Claude=