NAME

cpandeps - show a module on the CPAN's dependency tree.

DESCRIPTION

This program is a simple wrapper around CPAN::FindDependencies.

SYNOPSIS

    cpandeps CPAN::FindDependencies

    cpandeps CPAN::FindDependencies --perl 5.8.8 --cachedir ../foo/bar

    cpandeps CPAN::FindDependencies --showmoduleversions

Given a module name, this program will show you the module's dependency tree. It takes exactly the same arguments as the finddeps function of CPAN::FindDependencies, with the exception that nowarnings is turned *on* by default:

nowarnings

Warnings about modules where we can't find their META.yml or Makefile.PL, and so can't divine their pre-requisites, will be suppressed;

fatalerrors

Failure to get a module's dependencies will be a fatal error instead of merely emitting a warning;

perl

Use this version of perl to figure out what's in core. If not specified, it defaults to 5.005. Three part version numbers (eg 5.8.8) are supported but discouraged.

cachedir

A directory to use for caching. It defaults to no caching. Even if caching is turned on, this is only for META.yml or Makefile.PL files.

The cache is never automatically cleared out. It is your responsibility to clear out old data.

maxdepth

Cuts off the dependency tree at the specified depth. Your specified module is at depth 0, your dependencies at depth 1, their dependencies at depth 2, and so on.

If you don't specify any maxdepth at all it will grovel over the entire tree.

mirror

This can be provided more than once, if for example you want to use a private Pinto repository for your own code while using a public CPAN mirror for open source dependencies. The argument comes in two parts separated by a comma - the base URL from which to fetch files, and optionally the URL or a file from which to fetch the index 02packages.details.txt.gz file to use with that mirror.

  mirror https://cpan.mydomain.net,file:///home/me/mycache/02packages.txt.gz

If you want to use the default CPAN mirror (https://cpan.metacpan.org/) but also specify an index location you can use DEFAULT for the mirror URL.

So for example, to use your own special private mirror, including fetching 02packages from it, but also use the default mirror with a cached local copy of its 02packages, specify two mirrors thus:

  mirror => 'https://cpan.mydomain.net',
  mirror => 'DEFAULT,file:///home/me/mycache/02packages.txt.gz'

The index is cached for three minutes or until your process finishes, whichever is soonest. This is because it is HUMUNGOUS and parsing it takes ages even when it's loaded from a local disk, and I don't want the tests to take forever.

usemakefilepl

If set to true, then for any module that doesn't have a META.yml, try to use its Makefile.PL as well. Note that this involves downloading code from the Internet and running it. This obviously opens you up to all kinds of bad juju, hence why it is disabled by default. NB that this fetches Makefile.PL from https://fastapi.metacpan.org only so will not work for private mirrors. This is a deliberate choice, your own private code ought to be packaged properly with a META file, you should only care about divining dependencies from Makefile.PL if you rely on really old stuff on public CPAN mirrors.

Adds recommended modules to the list of dependencies, if set to a true value.

suggested

Adds suggested modules to the list of dependencies, if set to a true value.

It also takes the following extra parameter:

--showmoduleversions

If present, the required version of each module is also shown

It shows the module name, its distribution, and if any warnings were raised (such as if a module's dependencies couldn't be fetched) this is indicated with an asterisk before the module's name.

INCOMPATIBLE CHANGES

Up to version 2.49 you used the 02packages argument to specify where a cached 02packages.details.txt.gz could be found. That argument no longer exists as of version 3.00, use the mirror argument instead.

Up to version 2.49, maxdepth => 0 would incorrectly return the whole tree. From version 3.00 it cuts the tree off at its root so will only return the module that you asked about. Not very useful, but correct.

In version 2.49 you used the configreqs argument to specify that you were interested in configure-time requirements as well as build- and run-time requirements. That option no longer exists as of version 3.00, it will always report on configure, build, test, and run-time requirements.

TREE PRUNING

The dependency tree is pruned to remove duplicates. This means that even though Test::More, for example, is a dependency of almost everything on the CPAN, it will only be listed once.

WARNINGS, BUGS and FEEDBACK

This script has not been thoroughly tested.

I welcome feedback about my code, including constructive criticism. Bug reports should be made on Github or by email.

SEE ALSO

CPAN::FindDependencies

http://deps.cpantesters.org/

AUTHOR, LICENCE and COPYRIGHT

Copyright 2007 - 2020 David Cantrell <david@cantrell.org.uk>

This software is free-as-in-speech software, and may be used, distributed, and modified under the terms of either the GNU General Public Licence version 2 or the Artistic Licence. It's up to you which one you use. The full text of the licences can be found in the files GPL2.txt and ARTISTIC.txt, respectively.

CONSPIRACY

This software is also free-as-in-mason.