Perl::Critic::Policy::Modules::ProhibitConditionalUseStatements3pm

Affiliation

This Policy is part of the core Perl::Critic distribution.

Overview

Modules included via "use" are loaded at compile-time. Placing conditional logic around the "use" statement has no effect on whether the module will be loaded. Doing so can also serve to confuse the reader as to the author's original intent.

If you need to conditionally load a module you should be using "require" instead.

This policy will catch the following forms of conditional "use" statements:

    # if-elsif-else
    if ($a == 1) { use Module; }
    if ($a == 1) { } elsif ($a == 2) { use Module; }
    if ($a == 1) { } else { use Module; }
    # for/foreach
    for (1..$a) { use Module; }
    foreach (@a) { use Module; }
    # while
    while ($a == 1) { use Module; }
    # unless
    unless ($a == 1) { use Module; }
    # until
    until ($a == 1) { use Module; }
    # do-condition
    do { use Module; } if $a == 1;
    do { use Module; } while $a == 1;
    do { use Module; } unless $a == 1;
    do { use Module; } until $a == 1;
    # operator-do
    $a == 1 || do { use Module; };
    $a == 1 && do { use Module; };
    $a == 1 or do { use Module; };
    $a == 1 and do { use Module; };
    # non-string eval
    eval { use Module; };

Including a module via "use" in bare blocks, standalone do blocks, or string evals is allowed.

    # bare block
    { use Module; }
    # do
    do { use Module; }
    # string eval
    eval "use Module";

Configuration

This Policy is not configurable except for the standard options.