Composer option to use alternative to composer.json?

Question

I've just started using the Composer feature where you tell it to look at local directories for dependencies, so that you can develop a library and something that uses that library in parallel without having to push to git to update all the time, which is awesome. e.g.

"repositories": [
    {
        "type": "vcs",
        "url": "/documents/projects/github/guzzle"
    }
],

"require":{
    "guzzle/guzzle": "3.7.*@dev"
}

So when you do a composer update, Composer will pull in the version of Guzzle from the local directory, so you can test the code for a library in another application that uses that library without having to push to a repository between each code change.

However I just almost checked in the composer.json for my project with that set - which is obviously not going to work on anyone elses machine.

Is there anyway to tell composer to use a different file than composer.json, or other way to be able to tell composer to use local directories safely, without the high probability of accidentally committing a broken version of composer.json to your repository?

Answer 1

Use the COMPOSER environment variable:

env COMPOSER=composer-dev.json composer install

It has actually been available since at least 2012.