Jos Boumans > CPANPLUS-0.059_01 > CPANPLUS::inc

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Source   Latest Release: CPANPLUS-0.85_06

NAME ^

CPANPLUS::inc - runtime inclusion of privately bundled modules

SYNOPSIS ^

    ### set up CPANPLUS::inc to do it's thing ###
    BEGIN { use CPANPLUS::inc };

    ### enable debugging ###
    use CPANPLUS::inc qw[DEBUG];

DESCRIPTION ^

This module enables the use of the bundled modules in the CPANPLUS/inc directory of this package. These modules are bundled to make sure CPANPLUS is able to bootstrap itself. It will do the following things:

Put a coderef at the beginning of @INC

This allows us to decide which module to load, and where to find it. For details on what we do, see the INTERESTING MODULES section below. Also see the CAVEATS section.

Add the full path to the CPANPLUS/inc directory to $ENV{PERL5LIB.

This allows us to find our bundled modules even if we spawn off a new process. Although it's not able to do the selective loading as the coderef in @INC could, it's a good fallback.

METHODS ^

CPANPLUS::inc->inc_path()

Returns the full path to the CPANPLUS/inc directory.

CPANPLUS::inc->my_path()

Returns the full path to be added to @INC to load CPANPLUS::inc from.

CPANPLUS::inc->installer_path()

Returns the full path to the CPANPLUS/inc/installers directory.

CPANPLUS::inc->original_perl5lib

Returns the value of $ENV{PERL5LIB} the way it was when CPANPLUS::inc got loaded.

CPANPLUS::inc->original_perl5opt

Returns the value of $ENV{PERL5OPT} the way it was when CPANPLUS::inc got loaded.

CPANPLUS::inc->original_inc

Returns the value of @INC the way it was when CPANPLUS::inc got loaded.

CPANPLUS::inc->limited_perl5opt(@modules);

Returns a string you can assign to $ENV{PERL5OPT} to have a limited include facility from CPANPLUS::inc. It will roughly look like:

    -I/path/to/cpanplus/inc -MCPANPLUS::inc=module1,module2

CPANPLUS::inc->interesting_modules()

Returns a hashref with modules we're interested in, and the minimum version we need to find.

It would looks something like this:

    {   File::Fetch             => 0.06,
        IPC::Cmd                => 0.22,
        ....
    }

INTERESTING MODULES ^

CPANPLUS::inc doesn't even bother to try find and find a module it's not interested in. A list of interesting modules can be obtained using the interesting_modules method described above.

Note that all subclassed modules of an interesting module will also be attempted to be loaded, but a version will not be checked.

When it however does encounter a module it is interested in, it will do the following things:

Loop over your @INC

And for every directory it finds there (skipping all non directories -- see the CAVEATS section), see if the module requested can be found there.

Check the version on every suitable module found in @INC

After a list of modules has been gathered, the version of each of them is checked to find the one with the highest version, and return that as the module to use.

This enables us to use a recent enough version from our own bundled modules, but also to use a newer module found in your path instead, if it is present. Thus having access to bugfixed versions as they are released.

If for some reason no satisfactory version could be found, a warning will be emitted. See the DEBUG section for more details on how to find out exactly what CPANPLUS::inc is doing.

DEBUG ^

Since this module does Clever Things to your search path, it might be nice sometimes to figure out what it's doing, if things don't work as expected. You can enable a debug trace by calling the module like this:

    use CPANPLUS::inc 'DEBUG';

This will show you what CPANPLUS::inc is doing, which might look something like this:

    CPANPLUS::inc: Found match for 'Params::Check' in
    '/opt/lib/perl5/site_perl/5.8.3' with version '0.07'
    CPANPLUS::inc: Found match for 'Params::Check' in
    '/my/private/lib/CPANPLUS/inc' with version '0.21'
    CPANPLUS::inc: Best match for 'Params::Check' is found in
    '/my/private/lib/CPANPLUS/inc' with version '0.21'

CAVEATS ^

This module has 2 major caveats, that could lead to unexpected behaviour. But currently I don't know how to fix them, Suggestions are much welcomed.

On multiple use lib calls, our coderef may not be the first in @INC

If this happens, although unlikely in most situations and not happening when calling the shell directly, this could mean that a lower (too low) versioned module is loaded, which might cause failures in the application.

Non-directories in @INC

Non-directories are right now skipped by CPANPLUS::inc. They could of course lead us to newer versions of a module, but it's too tricky to verify if they would. Therefor they are skipped. In the worst case scenario we'll find the sufficing version bundled with CPANPLUS.

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