`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.

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 cpan -O reports them as outdated whenever that Perl trails the newest one CPAN has indexed, yet cpan -u can never upgrade them in place, since only a newer Perl carries newer core modules.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reaches CPAN before Homebrew publishes its bottle, so for a few weeks cpan -O flags the new release’s core modules as outdated against your current ones.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.

Initialize cli_errors list.

operation_notes: ClassVar = {'remove': "CPAN's client cannot uninstall a module at all."}¶

Per-operation hints rendered in the Notes column of the manager page’s Operations table.

Keyed by the Operations member name, each value is a single short sentence explaining why the manager lacks the operation, or what makes its implementation partial: the pointer a reader needs to judge whether the gap is one they could help close. Each sentence starts with a capital and closes with a period, and starts on a word rather than a code span, so the cell reads standalone beside its row. A blank cell stays silent: a manager documenting nothing documents no gap.

The full rationale never lives here: it belongs in a comment beside the implementing method (or beside this declaration, for an operation with no method to hang it on), so the sentence on the page stays a hint and the code keeps the story. The class docstring follows the same split: it keeps only what a user needs to run the tool day to day, never how mpm wraps it.

Validated by test_operation_notes, which also checks every key matches a real operation: a key outside the enum’s vocabulary would never reach a page.

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.

Left unset when the home page is the project’s repository, which repository_url names on its own, and when it is the project’s manual, which documentation_url names. Never inherited, like the other links.

documentation_url: str | None = 'https://metacpan.org/pod/CPAN'¶

Entry point of the project’s own documentation, or None when it has none.

The manual, the documentation site, or the man page of the CLI mpm drives: whichever page a user reads to learn the commands this manager wraps. Listed between homepage_url and repository_url in the links of the manager’s page, so a reader reaching for the tool’s reference finds it in the box of facts rather than in the prose below it.

Left unset where a link would state a fact twice or invent one: a tool documenting itself in its repository alone, whose README repository_url already reaches. A page about the ecosystem rather than the tool does not qualify either.

Where a project’s only site is its manual, that address belongs here and homepage_url stays unset: the slot names what the page is, and a reader reaching for the reference looks under the documentation link.

Never inherited, like every other link: the AUR helpers extending pacman each document themselves.

repository_url: str | None = 'https://github.com/andk/cpanpm'¶

Repository holding the project’s code, or None when it has no public one.

Linked from the manager’s documentation page. Also what the weekly metrics sample reads: docs/docs_update.py writes it into the [tool.repomatic.metrics] subjects of pyproject.toml when its forge answers the sampler, through a mirror for a forge that does not.

Never inherited, for the same reason as wikipedia_url: the AUR helpers extending pacman each live in a repository of their own.

wikipedia_url: str | None = 'https://en.wikipedia.org/wiki/CPAN'¶

English Wikipedia article about the project, or None when it has none.

Listed last in the links of the manager’s documentation page. The article covers the project that home page names, or is a redirect Wikipedia keeps under the project’s name, landing on the part of a broader article that describes it: Cargo_(software) opens the Cargo section of the Rust article. An article that merely mentions the project does not count, nor does one about a related subject: lazy is a Neovim plugin manager, and the Neovim article is not about it.

Never inherited: the metaclass resets it to None on any class not declaring its own. A subclass often wraps a distinct project, like the six AUR helpers extending pacman, and would otherwise present pacman’s article as its own. Documentation-only, like homepage_url.

logo: str | None = 'perl'¶

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.

Each keyword also becomes a content rule of the issue labeller, so its precision bar applies here: see generate_content_rules(). A subclass inherits the terms of its parent without claiming them, since test_manager_keywords_have_one_owner reads what a class declares itself.

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.

privileged_operations: ClassVar[frozenset[str]] = frozenset({'install', 'upgrade', 'upgrade_all'})¶

Operations with at least one command this manager marks privileged.

Keyed by the Operations member name, like operation_notes. An operation belongs here when a method implementing it passes sudo=True to run_cli() or build_cli(), with the method-to-operation map of METHOD_OPERATIONS. Those commands are the only ones the escalation policy (sudo, else default_sudo) wraps in the escalator. A definition derives the set from the operations it marks sudo = true.

prime_sudo() reads it to prompt only for the managers that escalate a command of the current run. With [mpm.overrides.gem] sudo = true, mpm sync asks for no password: the gem sources --update command of sync carries no marker. test_privileged_operations holds the set to the markers in the method bodies.

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]¶

Generates the CLI to upgrade all modules.

$ cpan -u

Return type:: tuple[str, ...]

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

Generates the CLI to upgrade one module.

$ cpan -i Try::Tiny

Return type:: tuple[str, ...]

meta_package_manager.managers.cpan module¶

`meta_package_manager.managers.cpan` module¶