Take WayGenerator (https://github.com/JeffreyWay/Laravel-4-Generators) for example

the installation instruction teaches us to install by adding

"require-dev": {
    "way/generators": "~2.0"
}

into composer.json. and add

'Way\Generators\GeneratorsServiceProvider'

into app/config/app.php ‘providers’ array

However, if you do composer install –no-dev    (install without require-dev packages)
or when you deploy to PaaS platform like heroku.

laravel artisan would go mad about it not being able to find Way\Generators\GeneratorsServiceProvider.

To fix it, one way is to add the following line into app/start/local.php  (your development environment)

App::register('Way\Generators\GeneratorsServiceProvider');

I have tested this and it works ok.  (reference)

The other way could be override providers variable with app/config/local/app.php and add our Provider there.  I havent verified this method yet.
but this suggestion came from the author of Way generators  (this forum post)

Problem solved.