puppet module is unusable at sites that do not have a compatible ::systemd namespace about puppet-puppet

[ekohl]

This drastically reduces the universal usability for a relatively small gain as far as code complexity is concerned.

I disagree with that, in particular the systemd timer and other ordering/workarounds are good examples where there's more code complexity than you'd think.

The ultimate fix for situations like these would require a feature in puppet that would enable a module to include another module in a private namespace. Referals from within the including module (i.e. in this particular case, the calls to ::systemd resources) would work as expected. However, the namespace would not be visible from modules other than the one including it.

Until such a private namespace puppet feature is available, published modules should take care not to trample on namespaces outside their own module.

While I agree that Puppet never solved namespacing quite right (other issues are around moving from one to another), I don't see how the current situation tramples on namespaces outside their own module. We have a dependency declared in our metadata.json and utilize it.

In the latter manifest the inclusion of the systemd::timer resource takes place even if the 'systemd timer' method is not enabled.

The reason for that is a user can switch between runmodes. That's why it is there: to ensure it's absent. You can override unavailable_runmodes to disable it. It would still leave the service overrides on the server side though which can be a problem.

[ekohl]

At this point I think the Vox Pupuli systemd module is very common. Even puppetlabs/postgresql has started to depend on it.