Overview

The goal of this library is to allow Composer plugin authors to have a unified way of defining strongly typed configuration in a standardized way.

Once a list of possible configuration values is defined, the specific value can come from one of three places:

1. A default value declared by the plugin.
2. The value set in composer.json
3. An environment variable.

Environment variables take precedence over values in composer.json or the default value, and values in composer.json take precedence over the default value.

This library was originally written as part of Composer Patches and was later extracted into a standalone project.