inc::latest(3)

NAME
inc::latest - use modules bundled in inc/ if they are newer than installed ones

SYNOPSIS
  # in Build.PL
  use inc::latest 'Module::Build';

DESCRIPTION
The "inc::latest" module helps bootstrap configure-time dependencies for CPAN distributions. These dependencies get bundled into the "inc" directory within a distribution and are used by Build.PL (or Makefile.PL).

Arguments to "inc::latest" are module names that are checked against both the current @INC array and against specially-named directories in "inc". If the bundled verison is newer than the installed one (or the module isn't installed, then, the bundled directory is added to the start of <@INC> and the module is loaded from there.

There are actually two variations of "inc::latest" -- one for authors and one for the "inc" directory. For distribution authors, the "inc::latest" installed in the system will record modules loaded via "inc::latest" and can be used to create the bundled files in "inc", including writing the second variation as "inc/latest.pm".

This second "inc::latest" is the one that is loaded in a distribution being installed (e.g. from Build.PL). This bundled "inc::latest" is the one that determines which module to load.

  Special notes on bundling
The "inc::latest" module creates bundled directories based on the packlist file of an installed distribution. Even though "inc::latest" takes module name arguments, it is better to think of it as bundling and making available entire distributions. When a module is loaded through "inc::latest", it looks in all bundled distributions in "inc/" for a newer module than can be found in the existing @INC array.

Thus, the module-name provided should usually be the "top-level" module name of a distribution, though this is not strictly required. For example, Module::Build has a number of heuristics to map module names to packlists, allowing users to do things like this:

  use inc::latest 'Devel::AssertOS::Unix';

even though Devel::AssertOS::Unix is contained within the Devel-CheckOS distribution.

At the current time, packlists are required. Thus, bundling dual-core modules may require a 'forced install' over versions in the latest version of perl in order to create the necessary packlist for bundling.

USAGE
When calling "use", the bundled "inc::latest" takes a single module name and optional arguments to pass to that module's own import method.

  use 'inc::latest' 'Foo::Bar' qw/foo bar baz/;

  Author-mode
You are in author-mode inc::latest if any of the Author-mode methods are available. For example:

  if ( inc::latest->can('write') ) {
    inc::latest->write('inc');
  }

loaded_modules()
      my @list = inc::latest->loaded_modules;

    This takes no arguments and always returns a list of module names requested for loading via "use inc::latest 'MODULE'", regardless of wether the load was successful or not.

write()
      inc::latest->write( 'inc' );

    This writes the bundled version of inc::latest to the directory name given as an argument. It almost all cases, it should be '"inc"'.

bundle_module()
      for my $mod ( inc::latest->loaded_modules ) {
        inc::latest->bundle_module($mod, $dir);
      }

    If $mod corresponds to a packlist, then this function creates a specially-named directory in $dir and copies all .pm files from the modlist to the new directory (which almost always should just be 'inc'). For example, if Foo::Bar is the name of the module, and $dir is 'inc', then the directory would be 'inc/inc_Foo-Bar' and contain files like this:

      inc/inc_Foo-Bar/Foo/Bar.pm

    Currently, $mod must have a packlist. If this is not the case (e.g. for a dual-core module), then the bundling will fail. You may be able to create a packlist by forced installing the module on top of the version that came with core Perl.

  As bundled in inc/
All methods are private. Only the "import" method is public.

AUTHOR
Eric Wilhelm <ewilhelm@cpan.org>, David Golden <dagolden@cpan.org>

COPYRIGHT
Copyright (c) 2009 by Eric Wilhelm and David Golden

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO
Module::Build