File::ShareDir::ProjectDistDir(3)

NAME
File::ShareDir::ProjectDistDir - Simple set-and-forget using of a '/share' directory in your projects root

VERSION
version 1.000009

DETERRENT
STOP!. Before using this distribution, some warnings MUST be considered.

The primary use-case for this module is targeted at development projects that are NOT intended for "CPAN".

As such, using it for "CPAN" is generally a bad idea, and better solutions generally involve the less fragile "Test::File::ShareDir", constraining any magical behavior exclusively to where it is needed: Tests.

Why?

•   Determining whether or not we are "dev" during "runtime" is a perilous heuristic that routinely fails with even slightly unusual file system layouts.

•   Auto-magical changing of behavior at "runtime" based on the above leads to many surprising and hard to debug problems.

For these reason, it is dangerous to rely on this distribution while striving to produce quality code.

If this documentation is not sufficient to dissuade you, I must strongly implore you to choose the "strict" mechanism, because that substantially reduces the possibilities with regards to false-positive of potential "dev" directories.

I have in mind to find a better mechanism to deliver the same objective, but no solutions are forthcoming at this time.

SYNOPSIS
  package An::Example::Package;

  use File::ShareDir::ProjectDistDir;

  # during development, $dir will be $projectroot/share
  # but once installed, it will be wherever File::Sharedir thinks it is.
  my $dir = dist_dir('An-Example')

Project layout requirements:

  $project/
  $project/lib/An/Example/Package.pm
  $project/share/   # files for package 'An-Example' go here.

You can use a directory name other than 'share' ( Assuming you make sure when you install that, you specify the different directory there also ) as follows:

  use File::ShareDir::ProjectDistDir ':all', defaults => {
    projectdir => 'templates',
  };

METHODS

  import
    use File::ShareDir::ProjectDistDir (@args);

This uses "Sub::Exporter" to do the heavy lifting, so most usage of this module can be maximized by understanding that first.

•   ":all"

        ->import( ':all' , .... )

    Import both "dist_dir" and "dist_file"

•   "dist_dir"

        ->import('dist_dir' , .... )

    Import the dist_dir method

•   "dist_file"

        ->import('dist_file' , .... )

    Import the dist_file method

•   "projectdir"

        ->import( .... , projectdir => 'share' )

    Specify what the project directory is as a path relative to the base of your distributions source, and this directory will be used as a "ShareDir" simulation path for the exported methods During development.

    If not specified, the default value 'share' is used.

•   "filename"

        ->import( .... , filename => 'some/path/to/foo.pm' );

    Generally you don't want to set this, as its worked out by caller() to work out the name of the file its being called from. This file's path is walked up to find the 'lib' element with a sibling of the name of your "projectdir".

•   "distname"

        ->import( .... , distname => 'somedistname' );

    Specifying this argument changes the way the functions are emitted at installed "runtime", so that instead of taking the standard arguments File::ShareDir does, the specification of the "distname" in those functions is eliminated.

    i.e:

        # without this flag
        use File::ShareDir::ProjectDistDir qw( :all );

        my $dir = dist_dir('example');
        my $file = dist_file('example', 'path/to/file.pm' );

        # with this flag
        use File::ShareDir::ProjectDistDir ( qw( :all ), distname => 'example' );

        my $dir = dist_dir();
        my $file = dist_file('path/to/file.pm' );

•   "strict"

        ->import( ... , strict => 1 );

    This parameter specifies that all "dist" "sharedirs" will occur within the "projectdir" directory using the following layout:

        <root>/<projectdir>/dist/<DISTNAME>/

    As opposed to

        <root>/<projectdir>

    This means if Heuristics misfire and accidentally find another distributions "share" directory, it will not pick up on it unless that "share" directory also has that layout, and will instead revert to the "installdir" path in @INC

    This parameter may become the default option in the future

    Specifying this parameter also mandates you MUST declare the "DISTNAME" value in your file somewhere. Doing otherwise is considered insanity anyway.

•   "defaults"

        ->import( ... , defaults => {
            filename => ....,
            projectdir => ....,
        });

    This is mostly an alternative syntax for specifying "filename" and "projectdir", which is mostly used internally, and their corresponding other values are packed into this one.

Sub::Exporter tricks of note.

Make your own sharedir util

    package Foo::Util;

    sub import {
        my ($caller_class, $caller_file, $caller_line )  = caller();
        if ( grep { /share/ } @_ ) {
            require File::ShareDir::ProjectDistDir;
            File::ShareDir::ProjectDistDir->import(
                filename => $caller_file,
                dist_dir => { distname => 'myproject' , -as => 'share' },
                dist_dir => { distname => 'otherproject' , -as => 'other_share' , projectdir => 'share2' },
                -into => $caller_class,
            );
        }
    }

    ....

    package Foo;
    use Foo::Util qw( share );

    my $dir = share();
    my $other_dir => other_share();

  build_dist_dir
    use File::ShareDir::ProjectDirDir ( : all );

    #  this calls
    my $coderef = File::ShareDir::ProjectDistDir->build_dist_dir(
      'dist_dir' => {},
      { defaults => { filename => 'path/to/yourcallingfile.pm', projectdir => 'share' } }
    );

    use File::ShareDir::ProjectDirDir ( qw( :all ), distname => 'example-dist' );

    #  this calls
    my $coderef = File::ShareDir::ProjectDistDir->build_dist_dir(
      'dist_dir' => {},
      { distname => 'example-dist', defaults => { filename => 'path/to/yourcallingfile.pm', projectdir => 'share' } }
    );

    use File::ShareDir::ProjectDirDir
      dist_dir => { distname => 'example-dist', -as => 'mydistdir' },
      dist_dir => { distname => 'other-dist',   -as => 'otherdistdir' };

    # This calls
    my $coderef = File::ShareDir::ProjectDistDir->build_dist_dir(
      'dist_dir',
      { distname => 'example-dist' },
      { defaults => { filename => 'path/to/yourcallingfile.pm', projectdir => 'share' } },
    );
    my $othercoderef = File::ShareDir::ProjectDistDir->build_dist_dir(
      'dist_dir',
      { distname => 'other-dist' },
      { defaults => { filename => 'path/to/yourcallingfile.pm', projectdir => 'share' } },
    );

    # And leverages Sub::Exporter to create 2 subs in your package.

Generates the exported 'dist_dir' method. In development environments, the generated method will return a path to the development directories 'share' directory. In non-development environments, this simply returns "File::ShareDir::dist_dir".

As a result of this, specifying the Distribution name is not required during development ( unless in "strict" mode ), however, it will start to matter once it is installed. This is a potential avenues for bugs if you happen to name it wrong.

In "strict" mode, the distribution name is ALWAYS REQUIRED, either at least at "import" or "dist_dir()" time.

  build_dist_file
    use File::ShareDir::ProjectDirDir ( : all );

    #  this calls
    my $coderef = File::ShareDir::ProjectDistDir->build_dist_file(
      'dist_file' => {},
      { defaults => { filename => 'path/to/yourcallingfile.pm', projectdir => 'share' } }
    );

    use File::ShareDir::ProjectDirDir ( qw( :all ), distname => 'example-dist' );

    #  this calls
    my $coderef = File::ShareDir::ProjectDistDir->build_dist_file(
      'dist_file' => {},
      { distname => 'example-dist', defaults => { filename => 'path/to/yourcallingfile.pm', projectdir => 'share' } }
    );

    use File::ShareDir::ProjectDirDir
      dist_file => { distname => 'example-dist', -as => 'mydistfile' },
      dist_file => { distname => 'other-dist',   -as => 'otherdistfile' };

    # This calls
    my $coderef = File::ShareDir::ProjectDistDir->build_dist_file(
      'dist_file',
      { distname => 'example-dist' },
      { defaults => { filename => 'path/to/yourcallingfile.pm', projectdir => 'share' } },
    );
    my $othercoderef = File::ShareDir::ProjectDistDir->build_dist_file(
      'dist_file',
      { distname => 'other-dist' },
      { defaults => { filename => 'path/to/yourcallingfile.pm', projectdir => 'share' } },
    );

    # And leverages Sub::Exporter to create 2 subs in your package.

Generates the 'dist_file' method.

In development environments, the generated method will return a path to the development directories 'share' directory. In non-development environments, this simply returns "File::ShareDir::dist_file".

Caveats as a result of package-name as stated in "build_dist_dir" also apply to this method.

SIGNIFICANT CHANGES

  1.000000
Strict Mode.

Using Strict Mode

    use File::ShareDir::ProjectDistDir ':all', strict => 1;
    use File::ShareDir::ProjectDistDir 'dist_dir' => { strict => 1 };

Why you should use strict mode

Starting with 1.000000, there is a parameter "strict" that changes how "sharedir" resolution performs.

Without strict:

    lib/...
    share/...

With strict

    lib/...
    share/dist/Dist-Name-Here/...

This technique greatly builds resilience to the long standing problem with "develop" vs "install" heuristic ambiguity.

Here at least,

    dist_dir('Dist-Name')

Will instead fall back to

    @INC/auto/share/dist/Dist-Name

When

    share/dist/Dist-Name

Does not exist.

This means if you have a layout like this:

    <DEVROOT>/inc/<a local::lib path here>
    <DEVROOT>/lib/<development files here>

Then when "Foo-Bar-Baz" is installed as:

    <DEVROOT>/inc/lib/Foo/Bar/Baz.pm
    <DEVROOT>/inc/lib/auto/share/dist/Foo-Bar-Baz

Then "Baz.pm" will not see the "DEVROOT" and assume "Hey, this is development" and then proceed to try finding files in "DEVROOT/share"

Instead, "DEVROOT" must have "DEVROOT/share/dist/Foo-Bar-Baz" too, otherwise it reverts to "DEVROOT/inc/lib/auto..."

"Path::Class" interfaces deprecated and dependency dropped.

If you have any dependence on this function, now is the time to get yourself off it.

Minimum Changes to stay with "Path::Class" short term.

As the dependency has been dropped on "Path::Class", if you have "CPAN" modules relying on "Path::Class" interface, you should now at a very minimum start declaring

    { requires => "Path::Class" }

This will keep your dist working, but will not be future proof against further changes.

Staying with "Path::Class" long term.

Recommended approach if you want to stay using the "Path::Class" interface:

    use File::ShareDir::... etc
    use Path::Class qw( dir file );

    my $dir = dir( dist_dir('Dist-Name') );

This should future-proof you against anything File::ShareDir may do in the future.

"Versioning Scheme arbitrary converted to float"

This change is a superficial one, and should have no bearing on how significant you think this release is.

It is a significant release, but the primary reason for the version change is simply to avoid compatibility issues in versions themselves.

However, outside that, "x.y.z" semantics are still intended to be semi-meaningful, just with less "." and more 0 ☺

"dev" path determination now deferred to call time instead of "use"

This was essentially a required change to make "strict" mode plausible, because strict mode _requires_ the "distname" to be known, even in the development environment.

This should not have any user visible effects, but please, if you have any problems, file a bug.

"file" component determination wrested from "File::ShareDir".

    dist_file('foo','bar')

Is now simply sugar syntax for

    path(dist_dir('foo'))->child('bar')

This should have no side effects in your code, but please file any bugs you experience.

( return value is still "undef" if the file does not exist, and still "croak"'s if the file is not a file, or unreadable, but these may both be subject to change )

  0.5.0 - Heuristics and Return type changes
New "devdir" heuristic

Starting with 0.5.0, instead of using our simple "lib/../share" pattern heuristic, a more advanced heuristic is used from the new "Path::FindDev" and "Path::IsDev".

This relies on a more "concrete" marker somewhere at the top of your development tree, and more importantly, checks for the existence of specific files that are not likely to occur outside a project root.

"lib" and "share" based heuristics were a little fragile, for a few reasons:

•   "lib" can, and does appear all over UNIX file systems, for purposes other than development project roots.

    For instance, have a look in "/usr/"

        /usr/bin
        /usr/lib
        /usr/share  ## UHOH.

    This would have the very bad side effect of anything installed in "/usr/lib" thinking its "in development".

    Fortunately, nobody seems to have hit this specific bug, which I suspect is due only to "/usr/lib" being a symbolic link on most x86_64 systems.

•   "lib" is also reasonably common within "CPAN" package names.

    For instance:

        lib::abs

    Which means you'll have a hierarchy like:

        $PREFIX/lib/lib/abs

    All you need for something to go horribly wrong would be for somebody to install a "CPAN" module named:

        share::mystuff

    Or similar, and instantly, you have:

        $PREFIX/lib/lib/
        $PREFIX/lib/share/

    Which would mean any module calling itself "lib::*" would be unable to use this module.

So instead, as of 0.5.0, the heuristic revolves around certain specific files being in the "dev" directory.

Which is hopefully a more fault resilient mechanism.

New Return Types

Starting with 0.5.0, the internals are now based on "Path::Tiny" instead of "Path::Class", and as a result, there may be a few glitches in transition.

Also, previously you could get a "Path::Class::*" object back from "dist_dir" and "dist_file" by importing it as such:

    use File::ShareDir::ProjectDistDir
        qw( dist_dir dist_file ),
        defaults => { pathclass => 1 };

Now you can also get "Path::Tiny" objects back, by passing:

    use File::ShareDir::ProjectDistDir
        qw( dist_dir dist_file ),
        defaults => { pathtiny => 1 };

For the time being, you can still get Path::Class objects back, it is deprecated since 1.000000

( In fact, I may even make 2 specific sub-classes of "PDD" for people who want objects back, as it will make the "API" and the code much cleaner )

AUTHOR
Kent Fredric <kentnl@cpan.org>

COPYRIGHT AND LICENSE
This software is copyright (c) 2017 by Kent Fredric <kentnl@cpan.org>.

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