I'm the maintainer of `zend-cache` and, right now, working on splitting the component into several components to be able to better define dependencies.
For example the APC(u) adapter will be an own component that requires the php extension `ext-apc(u)`.
The problem now are the adapters for Zend Data Cache as the extension names contain not allowed characters.
Error reported by `composer diagnose`:
require.ext-Zend Data Cache : invalid key, package names must be strings containing only [A-Za-z0-9_./-]
Error on trying to install dependencies:
The requested PHP extension ext-zend data cache * has the wrong version (0) installed. Install or enable PHP's zend data cache extension.
I also have filled up a bug report at composer (https://github.com/composer/composer/issues/6167)
but still having whitespaces in an extension name doesn't match naming convention of any extension I know.
Basically all other extensions I know using lower cased extension names only separated by `_`.