Development

Summary

Cause gem require to load a path other than the RubyGems installation.

Description

Intercept gem-require expression (require 'gem') and require version at alternative path (such as a development version).

Install

sudo gem install development

Why?

Use cases include:

Development work on a gem in the context of another gem that requires it and provides a problem context - cause development version to load without changing any code. This is particularly useful when the require statement is nested in other gems than the one providing the problem context.
Development of multiple side-by-side gems that are not yet released - use require 'gem-name' even before the gem has been installed.
Test development code for deployment contexts (and debug tests) before building/installing gem.

Usage

Enabling Development requires two things:

1. Require Development

begin ; require 'development' ; rescue LoadError ; end

Or a multi-line version if you prefer:

begin
  require 'development'
rescue LoadError
end

Doing this rather than simply requiring development ensures that Development can work transparently without requiring even a development dependency.

2. Configure Which Gems Development Should Override

The primary interface to development is the .development.rb configuration file, which should be placed in the user's home directory.

I would make project-specific .development.rb files a requirement (to avoid accidentally enabling it) but I don't think there is a reliable way to find the project directory based on the require. If you know a way, please let me know!

The .development.rb Configuration File

Short Example

The shortest possible example is a one-liner:

enable! :parallel_ancestry => '~/Projects/rp/ruby/parallel_ancestry'

Extended Example

But other configuration possibilities are provided for more complex configurations:

###
# Declare named locations to associate gems or gemsets with specific locations.
#   If a directory exists by name of gem or gemset it will be used automatically.
#   Otherwise the directory will have to be declared explicitly.
#
directory( :code, '~/Projects' )

###
# Paths can start with names of other paths.
#
directory( :ridiculous_power, :code, 'rp' )

directory( :ruby, :ridiculous_power, 'ruby' )
directory( :hooked_objects, :ruby, 'hooked_objects' )
directory( :compositing_objects, :ruby, 'compositing_objects' )

###
# Add gems or gemsets to directory.
#
directory( :ridiculous_power ).add( 'persistence', 'magnets' )

###
# Declare a gemset to group a set of gems and configure them by a single reference.
#
gemset( :ruby,                'module-cluster', 
                              'parallel_ancestry', 
                              'identifies_as' )

gemset( :hooked_objects,      'hash-hooked', 
                              'array-hooked', 
                              'array-sorted', 
                              'array-unique', 
                              'array-sorted-unique' )

gemset( :compositing_objects, 'hash-compositing', 
                              'array-compositing', 
                              'array-sorted-compositing', 
                              'array-unique-compositing', 
                              'array-sorted-unique-compositing' )

###
# Specify directory by gem or gemset.
#
gem( 'to_lambda' ).directory( :ruby )

###
# Enable all (no parameters) or specific gems.
#
enable! :ruby, :hooked_objects, :compositing_objects, :parallel_ancestry

Using Development with Bundler

Development plays well with bundler. The only caveat is that you have to require Development before Bundler.require:

require 'bundler'

begin ; require 'development' ; rescue LoadError ; end

Bundler.require

begin ; require 'development' ; rescue LoadError ; end

require 'bundler'

Bundler.require

License

(The MIT License)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.