# Dist::CheckConflicts - phpMan

## NAME
    [Dist::CheckConflicts] - declare version conflicts for your dist

## VERSION
    version 0.11

## SYNOPSIS
        use [Dist::CheckConflicts]
            -dist => 'Class-MOP',
            -conflicts => {
                'Moose'                => '1.14',
                '[namespace::autoclean]' => '0.08',
            },
            -also => [
                '[Package::Stash::Conflicts]',
            ];

        __PACKAGE__->check_conflicts;

## DESCRIPTION
    One shortcoming of the CPAN clients that currently exist is that they
    have no way of specifying conflicting downstream dependencies of
    modules. This module attempts to work around this issue by allowing you
    to specify conflicting versions of modules separately, and deal with
    them after the module is done installing.

    For instance, say you have a module "Foo", and some other module "Bar"
    uses "Foo". If "Foo" were to change its API in a
    non-backwards-compatible way, this would cause "Bar" to break until it
    is updated to use the new API. "Foo" can't just depend on the fixed
    version of "Bar", because this will cause a circular dependency (because
    "Bar" is already depending on "Foo"), and this doesn't express intent
    properly anyway - "Foo" doesn't use "Bar" at all. The ideal solution
    would be for there to be a way to specify conflicting versions of
    modules in a way that would let CPAN clients update conflicting modules
    automatically after an existing module is upgraded, but until that
    happens, this module will allow users to do this manually.

    This module accepts a hash of options passed to its "use" statement,
    with these keys being valid:

    -conflicts
        A hashref of conflict specifications, where keys are module names,
        and values are the last broken version - any version greater than
        the specified version should work.

    -also
        Additional modules to get conflicts from (potentially recursively).
        This should generally be a list of modules which use
        [Dist::CheckConflicts], which correspond to the dists that your dist
        depends on. (In an ideal world, this would be intuited directly from
        your dependency list, but the dependency list isn't available
        outside of build time).

    -dist
        The name of the distribution, to make the error message from
        check_conflicts more user-friendly.

    The methods listed below are exported by this module into the module
    that uses it, so you should call these methods on your module, not
    [Dist::CheckConflicts].

    As an example, this command line can be used to update your modules,
    after installing the "Foo" dist (assuming that "[Foo::Conflicts]" is the
    module in the "Foo" dist which uses [Dist::CheckConflicts]):

        perl -[MFoo::Conflicts] -e'print "$_\n"
            for map { $_->{package} } [Foo::Conflicts]->calculate_conflicts' | cpanm

    As an added bonus, loading your conflicts module will provide warnings
    at runtime if conflicting modules are detected (regardless of whether
    they are loaded before or afterwards).

## METHODS
  conflicts
    Returns the conflict specification (the "-conflicts" parameter to
    "import()"), as a hash.

  dist
    Returns the dist name (either as specified by the "-dist" parameter to
    "import()", or the package name which "use"d this module).

  check_conflicts
    Examine the modules that are currently installed, and throw an exception
    with useful information if any modules are at versions which conflict
    with the dist.

  calculate_conflicts
    Examine the modules that are currently installed, and return a list of
    modules which conflict with the dist. The modules will be returned as a
    list of hashrefs, each containing "package", "installed", and "required"
    keys.

## BUGS
    No known bugs.

    Please report any bugs to GitHub Issues at
    <<https://github.com/doy/dist-checkconflicts/issues>>.

## SEE ALSO
    [Module::Install::CheckConflicts]

    [Dist::Zilla::Plugin::Conflicts]

## SUPPORT
    You can find this documentation for this module with the perldoc
    command.

        perldoc [Dist::CheckConflicts]

    You can also look for information at:

    *   MetaCPAN

        <<https://metacpan.org/release/Dist-CheckConflicts>>

    *   Github

        <<https://github.com/doy/dist-checkconflicts>>

    *   RT: CPAN's request tracker

        <<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Dist-CheckConflicts>>

    *   CPAN Ratings

        <<http://cpanratings.perl.org/d/Dist-CheckConflicts>>

## AUTHOR
    Jesse Luehrs <<doy@tozt.net>>

## COPYRIGHT AND LICENSE
    This software is copyright (c) 2014 by Jesse Luehrs.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.