$_proxy has Undef Value

[goeldicom]

Describe the Bug

When $_proxy has no value, this error may appear:

Error while evaluating a Resource Statement
Evaluation Error: Operator '[]' is not applicable to an Undef Value. 
(file: /etc/puppetlabs/code/environments/production/modules/apt/manifests/ppa.pp, line: 68, column: 8)

Expected Behavior

$_proxy should be defined, perhaps this way:

$_proxy = $::apt::_proxy ? {
  undef  => { 'host' => '', 'port' => '', 'https' => false },
  default => $::apt::_proxy,
}

Environment

• Version [7.7.1}
• Platform [Ubuntu 20.04]

Additional Context

This should be done by the module, not in node manifests.

[kenyon]

Is that the right module version and error message? Line 68 of v7.7.1 (quite an old version) is this, which doesn't make sense with that error message:

puppetlabs-apt/manifests/ppa.pp

Line 68 in ef15f35

} else {