/ 
Perl-Critic-Policy-RegularExpressions-ProhibitRegexInStrings-0.001
/ Perl::Critic::Policy::RegularExpressions::ProhibitRegexInStrings

NAME

Perl::Critic::Policy::RegularExpressions::ProhibitRegexInStrings - Write a regular expression as qr//, not as a string that somebody compiles later.

VERSION

version 0.001

Perl::Critic::Policy::RegularExpressions::ProhibitRegexInStrings

A regular expression held in a string is compiled somewhere else, later, under the rules of that place and not of the file that wrote it. Two things go wrong with it, and nothing reports either:

  • The modifiers of the file do not reach it. Under use re '/aa', [[:alnum:]], \d and \w match only ASCII in the code of the file. In a string that JSON::Validator compiles as the pattern of a schema, they match any letter or digit of Unicode.

  • The policies of Perl::Critic do not read it. They read m//, qr//, s/// and split, and a string is a string to them. So '^[A-Za-z0-9]+$' passes ProhibitEnumeratedClasses and RequireExtendedFormatting, and its $, which also matches before a newline at the end, passes everything:

    pattern => '^[a-z_][a-z0-9_-]*$'    # reported: accepts "bob\n"

Write the expression as qr//, where the file and the policies can see it. Where a string is what the other end takes, give it the qr// in a string. A compiled expression keeps its modifiers when it becomes one, as (?^aa:...):

my $USER = qr/\A [[:lower:]_] [[:lower:][:digit:]_-]* \z/x;
...
pattern => "$USER"

This policy reports two kinds of string.

PROHIBITED

The value of a key that names a regular expression, pattern, regex or regexp by default, in a list of pairs:

{ type => 'string', pattern => '^[a-z]+$' }
validate( value => $v, regex => q{\A\d+\z} )
{ 'regexp' => "^$prefix-" }

A lexical scalar declared with a string, and used as a regular expression in its scope: interpolated into a match, a substitution or a qr//, bound with =~ or !~, or given to split:

my $sep = '\s*,\s*';
my @parts = split $sep, $line;

my $name = '[A-Za-z]+';
return unless $value =~ m/\A$name\z/;

ALLOWED

pattern => "$USER"                  # a qr// in a string
pattern => "${USER}"
pattern => qr/\A[a-z]+\z/
name    => '^not a pattern$'        # a key that names no expression
my $sep = qr/\s*,\s*/;              # a qr//
my $text = 'abc';                   # a string that no match uses
$value =~ m/\Q$literal\E/;          # see CAVEATS

CONFIGURATION

keys is the list of the keys whose value is a regular expression, separated by spaces. It replaces the default, pattern regex regexp:

[RegularExpressions::ProhibitRegexInStrings]
keys = pattern regex regexp match_re

CAVEATS

The second kind is found by its name, in the block that declares it and after the declaration. So a scalar that the block declares again with another value can be reported for a match that uses the second one, and a package variable that another file matches with is not seen.

A string that a match quotes with \Q is a literal, and not a pattern, but the policy does not look inside \Q. Say ## no critic (ProhibitRegexInStrings) there, or use index.

A key is matched by its name, whatever the hash is for. A pattern key that holds a glob or a sprintf format is reported too. Take the key out of keys for such a code base.

METHODS

supported_parameters

default_severity

default_themes

applies_to

violates

BUGS

Please report any bugs or feature requests on the bugtracker website https://github.com/Troglodyne-Internet-Widgets/perl-critic-policy-prohibitregexinstrings/issues

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.

AUTHORS

Current Maintainers:

  • George S. Baugh <george@troglodyne.net>

CONTRIBUTOR

troglodyne-robot <trogbot@troglodyne.net>

COPYRIGHT AND LICENSE

Copyright (c) 2026 Troglodyne LLC

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.