Perl::Critic::Policy::Variables::ProhibitLoopOnHash(3pm)

NAME
Perl::Critic::Policy::Variables::ProhibitLoopOnHash - Don't write loops on hashes, only on keys and values of hashes

VERSION
version 0.009

DESCRIPTION
When "looping over hashes," we mean looping over hash keys or hash values. If you forgot to call "keys" or "values" you will accidentally loop over both.

    foreach my $foo (%hash) {...}        # not ok
    action() for %hash;                  # not ok
    foreach my $foo ( keys %hash ) {...} # ok
    action() for values %hash;           # ok

An effort is made to detect expressions:

    action() for %hash ? keys %hash : ();                             # ok
    action() for %{ $hash{'stuff'} } ? keys %{ $hash{'stuff'} } : (); # ok

(Granted, the second example there doesn't make much sense, but I have found a variation of it in real code.)

CONFIGURATION
This policy is not configurable except for the standard options.

AUTHOR
Sawyer X, "xsawyerx@cpan.org"

THANKS
Thank you to Ruud H.G. Van Tol.

SEE ALSO
Perl::Critic

AUTHOR
Sawyer X

COPYRIGHT AND LICENSE
This software is Copyright (c) 2026 by Sawyer X.

This is free software, licensed under:

  The MIT (X11) License