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.IX Title "Perl::Critic::Policy::Variables::ProhibitPackageVars 3pm"
.TH Perl::Critic::Policy::Variables::ProhibitPackageVars 3pm 2025-07-14 "perl v5.42.0" "User Contributed Perl Documentation"
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.SH NAME
Perl::Critic::Policy::Variables::ProhibitPackageVars \- Eliminate globals declared with "our" or "use vars".
.SH AFFILIATION
.IX Header "AFFILIATION"
This Policy is part of the core Perl::Critic
distribution.
.SH DESCRIPTION
.IX Header "DESCRIPTION"
Conway suggests avoiding package variables completely, because they
expose your internals to other packages.  Never use a package variable
when a lexical variable will suffice.  If your package needs to keep
some dynamic state, consider using an object or closures to keep the
state private.
.PP
This policy assumes that you\*(Aqre using \f(CW\*(C`strict vars\*(C'\fR so that naked
variable declarations are not package variables by default.  Thus, it
complains you declare a variable with \f(CW\*(C`our\*(C'\fR or \f(CW\*(C`use vars\*(C'\fR, or if you
make reference to variable with a fully\-qualified package name.
.PP
.Vb 7
\&    $Some::Package::foo = 1;    # not ok
\&    our $foo            = 1;    # not ok
\&    use vars \*(Aq$foo\*(Aq;            # not ok
\&    $foo = 1;                   # not allowed by \*(Aqstrict\*(Aq
\&    local $foo = 1;             # bad taste, but technically ok.
\&    use vars \*(Aq$FOO\*(Aq;            # ok, because it\*(Aqs ALL CAPS
\&    my $foo = 1;                # ok
.Ve
.PP
In practice though, its not really practical to prohibit all package
variables.  Common variables like \f(CW$VERSION\fR and \f(CW@EXPORT\fR need to
be global, as do any variables that you want to Export.  To work
around this, the Policy overlooks any variables that are in ALL_CAPS.
This forces you to put all your exported variables in ALL_CAPS too,
which seems to be the usual practice anyway.
.SH CONFIGURATION
.IX Header "CONFIGURATION"
There is room for exceptions.  Some modules, like the core File::Find
module, use package variables as their only interface, and others like
Data::Dumper use package variables as their most common interface.
These module can be specified from your \fI.perlcriticrc\fR file, and the
policy will ignore them.
.PP
.Vb 2
\&    [Variables::ProhibitPackageVars]
\&    packages = Data::Dumper File::Find FindBin Log::Log4perl
.Ve
.PP
This is the default setting.  Using \f(CW\*(C`packages =\*(C'\fR  will override these
defaults.
.PP
You can also add packages to the defaults like so:
.PP
.Vb 2
\&    [Variables::ProhibitPackageVars]
\&    add_packages = My::Package
.Ve
.PP
You can add package \f(CW\*(C`main\*(C'\fR to the list of packages, but that will
only OK variables explicitly in the \f(CW\*(C`main\*(C'\fR package.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
Perl::Critic::Policy::Variables::ProhibitPunctuationVars
.PP
Perl::Critic::Policy::Variables::ProhibitLocalVars
.SH AUTHOR
.IX Header "AUTHOR"
Jeffrey Ryan Thalhammer <jeff@imaginative\-software.com>
.SH COPYRIGHT
.IX Header "COPYRIGHT"
Copyright (c) 2005\-2023 Imaginative Software Systems.  All rights reserved.
.PP
This program is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.  The full text of this license
can be found in the LICENSE file included with this module.