inc::latest - use modules bundled in inc/ if they are newer than installed ones
# in Build.PLuse inc::latest 'Module::Build';Theinc::latest module helps bootstrap configure-time dependencies for CPAN distributions. These dependencies get bundled into theinc directory within a distribution and are used by Build.PL (or Makefile.PL).
Arguments toinc::latest are module names that are checked against both the current@INC array and against specially-named directories ininc. 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 ofinc::latest -- one for authors and one for theinc directory. For distribution authors, theinc::latest installed in the system will record modules loaded viainc::latest and can be used to create the bundled files ininc, including writing the second variation asinc/latest.pm.
This secondinc::latest is the one that is loaded in a distribution being installed (e.g. from Build.PL). This bundledinc::latest is the one that determines which module to load.
Theinc::latest module creates bundled directories based on the packlist file of an installed distribution. Even thoughinc::latest takes module name arguments, it is better to think of it as bundling and making available entiredistributions. When a module is loaded throughinc::latest, it looks in all bundled distributions ininc/ 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.
When callinguse, the bundledinc::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/;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');}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.
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'.
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.pmCurrently, $modmust 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.
All methods are private. Only theimport method is public.
Eric Wilhelm <ewilhelm@cpan.org>, David Golden <dagolden@cpan.org>
Copyright (c) 2009 by Eric Wilhelm and David Golden
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