Debian Perl Policy Raphaël Hertzog hertzog@debian.org Brendan O'Dea bod@debian.org version 1.20 This document describes the packaging of Perl within the Debian GNU/Linux distribution and the policy requirements for packaged Perl programs and modules. Copyright © 1999, 2001 Software in the Public Interest

This manual is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

A copy of the GNU General Public License is available as /usr/share/common-licences/GPL in the Debian GNU/Linux distribution or on the World Wide Web at .

You can also obtain it by writing to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

Perl Packaging Versions

At any given time, the package perl should represent the current stable upstream version of Perl revision 5 (see ).

Only one package may contain the /usr/bin/perl binary and that package must either be perl or a dependency of that package (see ).

Where possible, Perl should be compiled to provide binary compatibility to at least the last released package version to allow a grace period over which binary module packages may be re-built against the new package (see ).

The perl-base package must provide perlapi-version for all released versions it is compatible with.

Base Package

In order to provide a minimal installation of Perl for use by applications without requiring the whole of Perl to be installed, the perl-base package contains the binary and a basic set of modules.

As Perl is currently used by such things as update-alternatives and some package maintainer scripts, it must be priority required and marked as essential.

Note that the perl-base package is intended only to provide for exceptional circumstances and the contents may change. In general only packages which form part of the base system should declare a dependency on perl-base rather than perl.

Module Path

Perl searches three different locations for modules, referred to in this document as core in which modules distributed with Perl are installed, vendor for packaged modules and site for modules installed by the local administrator.

The module search path (@INC) in the Debian packages has been ordered to include these locations in the following order: site (current)

Modules installed by the local administrator for the current version of Perl (see ). /usr/local/lib/perl/version /usr/local/share/perl/version Where version indicates the current Perl version ($Config{version}see the Config module).

vendor

Packaged modules (see ). /usr/lib/perl5 /usr/share/perl5

core

Modules included in the core Perl distribution. /usr/lib/perl/version /usr/share/perl/version

site (old)

site directories (as above) for modules installed with previously released perl packages for which the current package is binary compatible are included if present.

In each of the directory pairs above, the lib component is for binary (XS) modules, and share for architecture-independent (pure-perl) modules.

Documentation

The POD files and manual pages which do not refer to programs may be split out into a separate perl-doc package.

Manual pages distributed with Perl packages must be installed into the standard directories: Programs

Manual pages for programs and scripts are installed into /usr/share/man/man1 with the extension .1.

Modules

Manual pages for modules are installed into /usr/share/man/man3 with the extension .3perl.

Locally Installed Modules Site Directories

The Perl packages must provide a mechanism for the local administrator to install modules under /usr/local but must not create or remove those directories.

Modules should be installed to the directories described above in as site (current), programs to /usr/local/bin and manual pages under /usr/local/man.

Site Installation

The following commands should be sufficient in the majority of cases for the local administrator to install modules and must create directories as required: perl Makefile.PL make install

Packaged Modules Vendor Directories

The installation directory for Debian modules must be different from that for core and site modules.

The current Perl packaging uses the vendor directories for this purpose, which are at present as described in as vendor.

No version subdirectory exists on these directories as the dependencies for packaged modules (see ) should ensure that all work with the current perl package.

The Perl distribution includes many modules available separately from CPAN, which may have a newer version. The intent of the @INC ordering (described in ) is to allow such modules to be packaged to vendor which take precedence over the version in core. A packaged module which shadows a core module in this way must be a newer version.

Module packages must install manual pages into the standard directories (see ) using the extensions .1p and .3pm to ensure that no conflict arises where a packaged module duplicates a core module.

.packlist files should not be installed.

Module Package Names

Perl module packages should be named for the primary module provided. The naming convention for module Foo::Bar is libfoo-bar-perl. Packages which include multiple modules may additionally include provides for those modules using the same convention.

Vendor Installation

A module should use the following lines in the debian/rules build targetThe environment variable PERL_MM_OPT may be used to pass the INSTALLDIRS=vendor option in cases where Makefile.PL is not invoked directly from debian/rules: perl Makefile.PL INSTALLDIRS=vendor $(MAKE) OPTIMIZE="-O2 -g -Wall" and this one to install the results into the temporary tree: $(MAKE) install PREFIX=$(CURDIR)/debian/tmp/usr

A Build-Depends on perl (>= 5.6.0-16) is required.

Module Dependencies Architecture-Independent Modules

Architecture-independent modules which require core modules from the perl package must specify a dependency on that package.

Modules which contain explicit require version or use version statements must specify a dependency on perl or perl-base with the minimum required version, or more simply the current version.

In the absence of an explicit requirement, architecture-independent modules must depend on a minimum perl or perl-base version of 5.6.0-16 due to the changes in @INC introduced by that version.

Binary Modules

Binary modules must specify a dependency on either perl or perl-base with a minimum version of the perl package used to build the module, and must additionally depend on the expansion of perlapi-$Config{version} using the Config module.

Automating Perl Dependencies

Rather than hard-coding the dependencies into the control file, using a substitution such as ${perl:Depends} is suggested. This allows the dependencies to be determined as build time and written to the substvars file in the form perl:Depends=deps.

Packages built with debhelper may use to generate this substitution automatically. This additionally requires a versioned Build-Depends (or Build-Depends-Indep) on debhelper (>= 3.0.18).

Perl Programs Script Magic

All packaged perl programs must start with #!/usr/bin/perl and may append such flags as are required.

Program Dependencies

Programs which require core modules from the perl package must specify a dependency on that package.

Programs which contain explicit require version or use version statements must specify a dependency on perl or perl-base with the minimum required version, or more simply the current version.

As with modules, packages using debhelper may use to automatically generate dependences (see ).

Programs Embedding Perl Building Embedded Programs

Programs which embed a perl interpreter must declare a Build-Depends on libperl-dev.

The default linker options produced by perl -MExtUtils::Embed -e ldopts will link against the dynamic libperl. If programs wish to link to the static library, then -lperl should be changed to /usr/lib/libperl.a in those options.

Embedded Perl Dependencies

Dependencies for programs linking against the shared Perl library will be automatically created by dpkg-shlibdeps. Note however that the shared perl library package only suggests perl-base and packages requiring any core modules from the perl package must depend upon it explicitly.

Perl 6

The current stable upstream version at the time of this writing is 5.6.0. There is currently work in progress on the next major revision, although the specifications have yet to be finalised.

It is anticipated that when Perl 6 is released it will initially be packaged as perl6, install the binary as /usr/bin/perl6 and use different directories for packaged modules to perl: /usr/lib/perl6 /usr/share/perl6 This will allow Perl 5 and 6 packages and modules (which should be packaged as libfoo-bar-perl6), to co-exist for as long as required.

At some stage in the future when Perl 6 is sufficiently mature, the package naming may be reversed such that the perl package contains Perl 6 and the current package becomes perl5.