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Date: Wed, 30 Mar 2022 16:11:03 +0200
Cc: PHP Internals <internals@lists.php.net>
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To: Rowan Tommins <rowan.collins@gmail.com>
Subject: Re: [PHP-DEV] Undefined variables and the array append operator
From: claude.pache@gmail.com (Claude Pache)



> Le 29 mars 2022 =C3=A0 21:44, Rowan Tommins <rowan.collins@gmail.com> =
a =C3=A9crit :
>=20
> Hi all,
>=20
> If $foo is not defined, statements such as $foo +=3D 1 and $foo .=3D =
'blah' raise "undefined variable" Warnings in PHP 8, and will throw =
Errors in PHP 9. However, the very similar looking $foo[] =3D 1 succeeds =
silently.
>=20
> This seems odd to me, as "append to string" and "append to array" seem =
like very similar operations, with most of the same use cases and =
possible bugs.
>=20
>=20


Hi,

There are various subcases to consider:

(1) $x[] =3D 42; and $x['y'] =3D 42; where $x is undefined

(2) $x[] =3D 42; and  $x['y'] =3D 42; where $x is null

(3) $x['y'][] =3D 42;  and  $x['y']['w'] =3D 42; where $x is an array, =
and $x['y'] is undefined.

Of course, I agree that (1) should be an error.

The case (3) is similar to (1), but I think it is more controversial to =
change. I bet that they are various places in my code that take =
advantage of that feature, although personally I don=E2=80=99t mind to =
write $x['y'] ??=3D [ ]; when needed.

=E2=80=94Claude