meta_package_manager.managers.cpan module¶

class meta_package_manager.managers.cpan.CPAN[source]¶

Bases: PackageManager

The cpan client of the Comprehensive Perl Archive Network.

The tracked version is CPAN.pm’s library version, not the cpan script version printed on the same line.

Installs may require sudo when using the system Perl; local::lib gives user-local installs instead. The write operations carry dormant privileged markers: --sudo or a sudo = true override escalates them, while nothing escalates by default. cpan cannot uninstall a module, so no remove operation is declared.

Caution

Perl’s core modules (warnings, feature, POSIX, B, and the like) exist only inside Perl itself, with no standalone CPAN distribution, so their versions are tied to whichever Perl you run. cpan -O reports them as outdated whenever that Perl trails the newest one CPAN has indexed, yet cpan -u can never upgrade them in place, since only a newer Perl carries newer core modules. mpm relays both faithfully. This holds for any Perl, whether the macOS system one or a Homebrew install.

On the macOS system Perl at /usr/bin/perl, that Perl sits on the sealed, read-only system volume and cannot be replaced even with sudo, so the list never clears.

With a writable, user-controlled Perl ahead on your PATH (via brew install perl, since mpm drives whichever cpan comes first), the list does clear, but on a recurring delay: each yearly Perl release reaches CPAN before Homebrew publishes its bottle, so for a few weeks cpan -O flags the new release’s core modules as outdated against your current ones. Perl 5.44.0, released 2026-07-15, opened one such window against the 5.42 series Homebrew still bottled. Running brew upgrade perl once the new bottle lands moves your core modules to the new set and clears the list, until the next release reopens the window.

If you do not track Perl modules with cpan at all, disable the manager entirely: set cpan = false in your mpm config, or pass --no-cpan. See #1983 for the original report.

Note

On Debian and Ubuntu, Perl reaches its core modules through @INC directories that are symlinks, like /usr/share/perl/5.40 pointing to 5.40.1. cpan -l does not enter a directory it is given as a symlink, so it lists none of those modules, while cpan -O still reports them as outdated. mpm therefore runs cpan -l a second time with the resolved directories in PERL5LIB, and adds the modules that only this second run finds.

Initialize cli_errors list.

name: str = 'Perl CPAN'¶

Return package manager’s common name.

Default value is based on class name.

homepage_url: str | None = 'https://www.cpan.org'¶

Home page of the project, only used in documentation for reference.

Slug of the brand mark standing for this manager in the documentation.

Names an SVG vendored under docs/assets/managers/, whose provenance and license are recorded in docs/assets/managers/logos.yaml. Inlined at the top of the manager’s page by meta_package_manager._docs; a manager leaving it unset keeps the page’s default package glyph.

Several managers legitimately share one slug, either because they wrap the same upstream (brew and cask) or because the tool has no mark of its own and its ecosystem’s stands in (apt under Debian’s swirl, cargo under Rust’s gear). Documentation-only, like homepage_url: no CLI output reads it.

keywords: tuple[str, ...] = ('perl',)¶

Well-known names for this manager that its id does not already carry.

Merged into the PyPI keywords of pyproject.toml by update_keywords() of docs/docs_update.py, alongside every manager ID and the globally curated KEYWORDS_EXTRAS. Declare an alias here rather than in that tuple whenever it names this manager: an alias living beside the class it describes cannot outlive it, where a central entry silently rots once the manager is renamed or dropped.

Reserve KEYWORDS_EXTRAS for terms belonging to no manager in particular, like cyclonedx or package manager. Documentation-only: no CLI output reads it.

platforms: frozenset[Platform] | Group | Platform | Iterable[Platform | Group] = frozenset({Platform(id='aix', name='IBM AIX'), Platform(id='almalinux', name='AlmaLinux'), Platform(id='alpine', name='Alpine Linux'), Platform(id='altlinux', name='ALT Linux'), Platform(id='amzn', name='Amazon Linux'), Platform(id='android', name='Android'), Platform(id='arch', name='Arch Linux'), Platform(id='buildroot', name='Buildroot'), Platform(id='cachyos', name='CachyOS'), Platform(id='centos', name='CentOS'), Platform(id='chromeos', name='ChromeOS'), Platform(id='clearlinux', name='Clear Linux OS'), Platform(id='cloudlinux', name='CloudLinux OS'), Platform(id='crux', name='CRUX'), Platform(id='cygwin', name='Cygwin'), Platform(id='debian', name='Debian'), Platform(id='dragonfly_bsd', name='DragonFly BSD'), Platform(id='endeavouros', name='EndeavourOS'), Platform(id='exherbo', name='Exherbo Linux'), Platform(id='fedora', name='Fedora'), Platform(id='freebsd', name='FreeBSD'), Platform(id='generic_linux', name='Generic Linux'), Platform(id='gentoo', name='Gentoo Linux'), Platform(id='guix', name='Guix System'), Platform(id='haiku', name='Haiku'), Platform(id='hurd', name='GNU/Hurd'), Platform(id='ibm_powerkvm', name='IBM PowerKVM'), Platform(id='illumos', name='illumos'), Platform(id='kali', name='Kali Linux'), Platform(id='kvmibm', name='KVM for IBM z Systems'), Platform(id='linuxmint', name='Linux Mint'), Platform(id='macos', name='macOS'), Platform(id='mageia', name='Mageia'), Platform(id='mandriva', name='Mandriva Linux'), Platform(id='manjaro', name='Manjaro Linux'), Platform(id='midnightbsd', name='MidnightBSD'), Platform(id='netbsd', name='NetBSD'), Platform(id='nixos', name='NixOS'), Platform(id='nobara', name='Nobara'), Platform(id='nutyx', name='NuTyX'), Platform(id='openbsd', name='OpenBSD'), Platform(id='opensuse', name='openSUSE'), Platform(id='openwrt', name='OpenWrt'), Platform(id='oracle', name='Oracle Linux'), Platform(id='os400', name='IBM i'), Platform(id='parallels', name='Parallels'), Platform(id='pidora', name='Pidora'), Platform(id='pikaos', name='PikaOS'), Platform(id='raspbian', name='Raspbian'), Platform(id='rhel', name='RedHat Enterprise Linux'), Platform(id='rocky', name='Rocky Linux'), Platform(id='scientific', name='Scientific Linux'), Platform(id='slackware', name='Slackware'), Platform(id='sles', name='SUSE Linux Enterprise Server'), Platform(id='slitaz', name='SliTaz GNU/Linux'), Platform(id='solaris', name='Solaris'), Platform(id='solus', name='Solus'), Platform(id='sourcemage', name='Source Mage GNU/Linux'), Platform(id='sunos', name='SunOS'), Platform(id='tuxedo', name='Tuxedo OS'), Platform(id='ubuntu', name='Ubuntu'), Platform(id='ultramarine', name='Ultramarine'), Platform(id='void', name='Void Linux'), Platform(id='windows', name='Windows'), Platform(id='wsl1', name='Windows Subsystem for Linux v1'), Platform(id='wsl2', name='Windows Subsystem for Linux v2'), Platform(id='xenserver', name='XenServer')})¶

List of platforms supported by the manager.

Allows for a mishmash of platforms and groups of platforms. Will be normalized into a frozenset of Platform instances at instantiation.

requirement: str | None = '>=1.64'¶

Version requirement specifier.

Supports a comma-separated range of constraints (e.g. ">=1.20.0,<2.0.0"). A bare version string like "1.20.0" is treated as >=1.20.0.

Parsed by meta_package_manager.version.VersionRange.

Defaults to None, which deactivates version check entirely.

extra_env: ClassVar = {'PERL_MM_USE_DEFAULT': '1'}¶

Suppress the interactive configuration cpan may launch on first run.

version_cli_options: tuple[str, ...] = ('-v',)¶

CLI options used to produce the version of the package manager.

The raw output produced by the package manager CLI will be parsed with the version_regexes below to extract the version number.

version_regexes: tuple[str, ...] = ('CPAN\\.pm\\s+version\\s+(?P<version>\\S+)',)¶

Read the CPAN.pm version, the meaningful one, rather than the script’s.

$ cpan -v
Loading internal logger. Log::Log4perl recommended for better logging
>(info): /usr/bin/cpan script version 1.678, CPAN.pm version 2.36
property installed: Iterator[Package]¶

Fetch installed modules.

$ cpan -l
Loading internal logger. Log::Log4perl recommended for better logging
Glib    1.3294
Cairo   1.109
Clone   0.47
Text::CharWidth 0.04
Text::Iconv     1.7
HTML::TokeParser        3.83
HTML::PullParser        3.83
HTML::Entities  3.83
HTML::Parser    3.83
HTML::LinkExtor 3.83
HTML::Filter    3.83
HTML::HeadParser        3.83
Net::SSLeay     1.94
Net::DBus       1.2.0
Net::DBus::Error        undef
Net::DBus::Callback     undef
Net::DBus::Reactor      undef

cpan -l walks each @INC directory with File::Find, which does not enter a starting directory that is a symlink. When _symlinked_inc_targets() finds such directories, a second run puts their resolved paths in PERL5LIB, which cpan -l then walks too:

$ PERL5LIB=/usr/share/perl/5.40.1:/usr/lib/aarch64-linux-gnu/perl/5.40.1 cpan -l
Loading internal logger. Log::Log4perl recommended for better logging
UNIVERSAL       1.17
version 0.9930
English 1.11
_charnames      1.50
fields  2.25

From that second run, only the modules the first one missed are kept. PERL5LIB puts the resolved directories ahead of the rest of @INC, and Debian’s perl-base package ships a second copy of some core modules, like strict and warnings: keeping every row would list those modules twice.

Todo

Drop the second run, with _sibling_perl() and _symlinked_inc_targets(), once a fixed cpan -l reaches the Perl that Debian and Ubuntu ship. Reported upstream as andk/cpanpm#202.

property outdated: Iterator[Package]¶

Fetch outdated modules.

$ cpan -O
Loading internal logger. Log::Log4perl recommended for better logging
Reading '/home/user/.cpan/Metadata'
  Database was generated on Wed, 16 Sep 2026 14:17:02 GMT
Module Name                                Local    CPAN
-------------------------------------------------------------------------
App::Cpan                                 1.6780  1.6790
App::Prove                                3.4800  3.5200
App::Prove::State                         3.4800  3.5200
App::Prove::State::Result                 3.4800  3.5200
App::Prove::State::Result::Test           3.4800  3.5200
Archive::Tar                              3.0200  3.1200
Archive::Tar::Constant                    3.0200  3.1200
cli_names: tuple[str, ...] = ('cpan',)¶

List of CLI names the package manager is known as.

This list of recognized CLI names is ordered by priority. That way we can influence the search of the right binary.

..hint::

This was helpful in the case of the Python transition from 2.x to 3.x, where multiple versions of the same executable were named python or python3.

By default, this property’s value is derived from the manager’s ID (see the MetaPackageManager.__init__ method above).

id: str = 'cpan'¶

Package manager’s ID.

Derived by defaults from the lower-cased class name in which underscores _ are replaced by dashes -.

This ID must be unique among all package manager definitions and lower-case, as they’re used as feature flags for the mpm CLI.

install(package_id, version=None)[source]¶

Install one module.

A bare module name installs it.

$ cpan Try::Tiny
Return type:

str

virtual: bool = False¶

Should we expose the package manager to the user?

Virtual package manager are just skeleton classes used to factorize code among managers of the same family.

upgrade_all_cli()[source]¶

Generate the CLI to upgrade all modules.

$ cpan -u
Return type:

tuple[str, ...]

upgrade_one_cli(package_id, version=None)[source]¶

Generate the CLI to upgrade one module.

$ cpan -i Try::Tiny
Return type:

tuple[str, ...]