Creating a Composer Package with its own Dependency

gistfile1.txt

I'm trying to set up composer for a package I maintain called Zymurgy:CM, which is on github but not on packagist.  I created a 'composer' branch which has the following composer.json file:

{
    "name": "zymurgy/zymurgy-cm",
    "type": "library",
    "description": "Zymurgy:CM Content Management",
    "license":"MIT",
    "authors": [
        {
            "name": "Vic Metcalfe",
            "email": "[email protected]",
            "homepage": "http://vicmetcalfe.com",
            "role": "Developer"
        }
    ],
    "require": {
        "php": ">=5.3.0",
        "minmb/phpmailer": "dev-master"
    }
}

If I run composer install from this project it installs phpmailer no problem.

Now I want to use my package in a test project, so I set up a custom repository to point to my github, and that on its own works fine, but with the above dependency on phpmailer installing my package fails.  Here's the test project's composer.json:

{
    "name": "test/test",
    "repositories": [
        {
            "type": "vcs",
            "url": "http://github.com/zymsys/zymurgy-cm"
        }
    ],
    "require": {
        "zymurgy/zymurgy-cm": "dev-composer"
    }
}

When I do a composer install with this, I get the following error:

Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Installation request for zymurgy/zymurgy-cm dev-composer -> satisfiable by zymurgy/zymurgy-cm dev-composer.
    - zymurgy/zymurgy-cm dev-composer requires minmb/phpmailer dev-master -> no matching package found.

Potential causes:
 - A typo in the package name
 - The package is not available in a stable-enough version according to your minimum-stability setting
   see <https://groups.google.com/d/topic/composer-dev/_g3ASeIFlrc/discussion> for more details.

Read <http://getcomposer.org/doc/articles/troubleshooting.md> for further common problems.

I followed the above links, but I'm still missing something.