only install curl if it isn't defined elsewhere

[ghost]

If ensure_package() is used with a conventional resource declaration
such as package { 'curl': ensure => present, }, it could result in
a duplicate resource error. This commit ensures that curl is not
declared if it's already defined elsewhere, such as a site-wide packages
class (this is fairly common behavior).

Considering that $install_dependencies defaults to false in init.pp,
this commit/PR probably satisfies most of the use cases. But you might
want to consider the use of ensure_package() in the rest of the
dependencies classes.

[carlossg]

if you have package { 'curl': ensure => present, } then ensure_packages will not install curl. Only in the case that your package definition has more attributes

[ghost]

Maybe my message / use case wasn't clear enough then; in the interest of brevity I just included a quick in-line case, but you're correct. As soon as you add any other parameters...

package { 'puppet':
  ensure => installed,
  alias  => 'curl',
}

... applying maestrodev/rvm will result in a duplicate resource error. Considering $install_dependencies defaults to false, I wouldn't expect this module to attempt to install any packages. But since curl is necessary to get rvm downloaded and installed, it's clearly needed here, and removing it completely would hurt users more than it would help.

The nicest way to work around all that is to just wrap it in a if ! defined(), as I've done in this PR. This wouldn't affect existing usage of the module, and would allow users with curl defined elsewhere to apply maestrodev/rvm without errors. It worked for me anyway.

[carlossg]

yes, that's a known issue with ensure_packages / ensure_resources, the hash needs to match exactly with ensure => present so it is not redefined