Perl::...ignAref(3pm)

💖 NAME 💖

Perl::Critic::Policy::Plicease::ProhibitArrayAssignAref — bestie, this is a Perl::Critic policy, and its whole vibe is: don't assign an anonymous arrayref to an array. That's it. That's the policy. (It lives in section 3pm, and yes the page header is abbreviated as Perl::...ignAref(3pm) because manpages love to be dramatic and truncate. 🙈)

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✨ VERSION ✨

version 100.00

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🦋 DESCRIPTION 🦋

Okay so, first things first: this policy is a fork of Perl::Critic::Policy::ValuesAndExpressions::ProhibitArrayAssignAref. The glow-up? It differs from the original by not having a dependency on List::MoreUtils. Slay. But also — and I have to be honest with you — it is unfortunately still licensed as GPL3. 💀 We love a freedom-respecting queen but we also love permissive licensing, y'know?

So what does it actually do? It asks you, politely but firmly, not to assign an anonymous arrayref to an array:

@array = [ 1, 2, 3 ];       # bad

The idea (and it's a good idea, no cap) is that it's rather unclear whether an arrayref is intended, or whether you might have meant to write a list like:

@array = ( 1, 2, 3 );

This policy is filed under the "bugs" theme (see "POLICY THEMES" in Perl::Critic) — like, for the chance that [] is a mistake, and since even if it's correct, it will likely make anyone reading it wonder. It's giving ✨confusion✨ and we simply cannot have that in the group chat.

A single arrayref can still be assigned to an array, but you gotta use parens to make it clear:

@array = ( [1,2,3] );       # ok

Dereferences or array and hash slices (see "Slices" in perldata) are recognised as an array target and treated similarly, bestie:

@$ref = [1,2,3];            # bad assign to deref
@{$ref} = [1,2,3];          # bad assign to deref
@x[1,2,3] = ['a','b','c'];  # bad assign to array slice
@x{'a','b'} = [1,2];        # bad assign to hash slice

🌸 List Assignment Parens 🌸

Not me needing to clarify this: this policy is not a blanket requirement for () parens on array assignments. It's normal and unambiguous to have a function call or grep etc. without parens. Lowkey iconic behaviour, actually.

@array = foo();                    # ok
@array = grep {/\.txt$/} @array;   # ok

The only likely problem from lack of parens in such cases is that the , comma operator has lower precedence than = (see perlop), so something like

@array = 1,2,3;   # oops, not a list

actually means

@array = (1);
2;
3;

😭 Bestie. That's not a list. That's three statements wearing a trench coat.

Normally the remaining literals in void context provoke a warning from Perl itself, so at least Perl is also side-eyeing you.

An intentional single element assignment is quite common as a statement, for instance:

@ISA = 'My::Parent::Class';   # ok

And for reference, the range operator precedence is high enough:

@array = 1..10;               # ok

But of course parens are needed if you're concatenating some disjoint ranges with the comma operator:

@array = (1..5, 10..15);      # parens needed

The qw form gives a list too:

@array = qw(a b c);           # ok

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👀 SEE ALSO 👀

• Perl::Critic
• Perl::Critic::Policy::ValuesAndExpressions::ProhibitArrayAssignAref

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🌈 HOME PAGE 🌈

<https://github.com/uperl/Perl-Critic-Policy-Plicease-ProhibitArrayAssignAref>

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🎀 COPYRIGHT 🎀

Copyright 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2019, 2021 Kevin Ryde

Perl-Critic-Policy-Plicease-ProhibitArrayAssignAref is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version.

Perl-Critic-Policy-Plicease-ProhibitArrayAssignAref is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with Perl-Critic-Policy-Plicease-ProhibitArrayAssignAref. If not, see <http://www.gnu.org/licenses>.

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💜 AUTHOR 💜

• Original author: Kevin Ryde
• Current maintainer: Graham Ollis <plicease@cpan.org>

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👑 COPYRIGHT AND LICENSE 👑

This software is Copyright (c) 2011-2021 by Kevin Ryde.

This is free software, licensed under:

The GNU General Public License, Version 3, June 2007

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And that's the whole page, bestie — this doc was served up by perl v5.40.1, dated 2025-03-20, and that footer was literally its little signature at the bottom of the page. Go forth and parenthesise responsibly. 💅✨