.\" Automatically generated by Pod::Man 4.14 (Pod::Simple 3.40) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. Capital omega is used to do unbreakable dashes and .\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff, .\" nothing in troff, for use with C<>. .tr \(*W- .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' .ie n \{\ . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} .el\{\ . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" ======================================================================== .\" .IX Title "Perl::Critic::Policy::ValuesAndExpressions::ProhibitDuplicateHashKeys 3pm" .TH Perl::Critic::Policy::ValuesAndExpressions::ProhibitDuplicateHashKeys 3pm "2021-02-28" "perl v5.32.1" "User Contributed Perl Documentation" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" Perl::Critic::Policy::ValuesAndExpressions::ProhibitDuplicateHashKeys \- disallow duplicate literal hash keys .SH "DESCRIPTION" .IX Header "DESCRIPTION" This policy is part of the \f(CW\*(C`Perl::Critic::Pulp\*(C'\fR add-on. It reports duplicate literal hash keys in a hash assignment or anonymous hashref. .PP .Vb 4 \& my %hash = (red => 1, \& green => 2, \& red => 3, # bad \& ); \& \& my $hashref = { red => 1, \& red => 3, # bad \& }; .Ve .PP Writing duplicate literal keys is probably a mistake or too much cut and paste, and if the values are different will make it unclear to human readers what was meant. On that basis this policy is under the \*(L"bugs\*(R" theme and medium severity (see \*(L"\s-1POLICY THEMES\*(R"\s0 in Perl::Critic). .PP Perl is happy to run code like the above. The value of the last \*(L"red\*(R" is stored. As runtime behaviour, this is good since you can give defaults which further values from a caller or similar can replace. For example, .PP .Vb 6 \& sub new { \& my $class = shift; \& return bless { foo => \*(Aqdefault\*(Aq, \& bar => \*(Aqdefault\*(Aq, \& @_ }, $class; \& } \& \& MyClass\->new (foo => \*(Aqcaller value\*(Aq); # overriding \*(Aqdefault\*(Aq .Ve .SS "Expressions" .IX Subsection "Expressions" Expressions within a hash list cannot be checked in general. Some concatenations of literals are recognised though they're probably unusual. .PP .Vb 2 \& my %hash = (ab => 1, \& \*(Aqa\*(Aq.\*(Aqb\*(Aq => 2); # bad \& \& my %hash = (_\|_PACKAGE_\|_.\*(Aqa\*(Aq => 1, \& _\|_PACKAGE_\|_.\*(Aqa\*(Aq => 2); # bad .Ve .PP Function calls etc within a list might return an odd or even number of values. Fat commas \f(CW\*(C`=>\*(C'\fR are taken as indicating a key when in doubt. .PP .Vb 3 \& my %hash = (blah() => 1, # guided by => \& a => 2, \& a => 3); # bad \& \& my %hash = (blah(), \& a => 2, # guided by => \& a => 3); # bad .Ve .PP A hash substitution is always an even number of arguments, .PP .Vb 3 \& my %hash = (a => 1, \& %blah, # even number \& a => 5); # bad, duplicate .Ve .PP \&\f(CW\*(C`qw()\*(C'\fR words are recognised too .PP .Vb 2 \& my %hash = (qw(foo value1 \& foo value2)); # bad .Ve .SS "Disabling" .IX Subsection "Disabling" If you don't care about this you can always disable \&\f(CW\*(C`ProhibitDuplicateHashKeys\*(C'\fR from your \fI.perlcriticrc\fR file in the usual way (see \*(L"\s-1CONFIGURATION\*(R"\s0 in Perl::Critic), .PP .Vb 1 \& [\-ValuesAndExpressions::ProhibitDuplicateHashKeys] .Ve .SH "SEE ALSO" .IX Header "SEE ALSO" Perl::Critic::Pulp, Perl::Critic .PP Perl::Critic::Policy::CodeLayout::RequireTrailingCommas, Perl::Critic::Policy::CodeLayout::RequireTrailingCommaAtNewline .SH "HOME PAGE" .IX Header "HOME PAGE" http://user42.tuxfamily.org/perl\-critic\-pulp/index.html .SH "COPYRIGHT" .IX Header "COPYRIGHT" Copyright 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2019, 2020, 2021 Kevin Ryde .PP Perl-Critic-Pulp is free software; you can redistribute it and/or modify it under the terms of the \s-1GNU\s0 General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. .PP Perl-Critic-Pulp is distributed in the hope that it will be useful, but \&\s-1WITHOUT ANY WARRANTY\s0; without even the implied warranty of \s-1MERCHANTABILITY\s0 or \s-1FITNESS FOR A PARTICULAR PURPOSE.\s0 See the \s-1GNU\s0 General Public License for more details. .PP You should have received a copy of the \s-1GNU\s0 General Public License along with Perl-Critic-Pulp. If not, see .