puppet-lint-optional_default-check

A puppet-lint plugin to check that Optional parameters don't default to something other than undef.

Installing

From the command line

$ gem install puppet-lint-optional_default-check

In a Gemfile

gem 'puppet-lint-optional_default-check', :require => false

Checks

`Optional` parameter defaults to something other than `undef`

An Optional parameter in Puppet is one where undef is an allowed value.

It is normally a mistake to set the default of an Optional parameter to something other than undef. This is because it's not possible to 'pass' undef as the value to use for a parameter when declaring a class or defined type. When you try to set a parameter to undef, Puppet actually uses the class's default value for that parameter, not undef itself.

(The caveat is that it is possible to use hiera to override a non undef default back to undef, but in practice, doing this is quite rare.)

A defined type with an mandatory (no default), Optional parameter will raise a warning.

The plugin will not raise a warning if a class Optional parameter doesn't have a default. Mandatory parameters can have defaults set in hiera, and several modules do use ~ for this.

What you have done

class foo (
  Optional[Integer] $port = 8080,
){
}

What you should have done

class foo (
  Integer $port = 8080,
){
}

class foo (
  Optional[Integer] $port = undef,
){
}

Copyright

Licensed under the MIT License.