validate_legacy fails catalog compilation under Puppet 8 strict deprecation handling

Summary

validate_legacy() still calls stdlib's deprecation() helper directly. Under Puppet 8 / OpenVox 8, where strict=error is the default behaviour, this deprecation call can raise a hard evaluation error before validate_legacy() performs its actual type assertion.

This appears to be an uncovered validate_legacy() instance of the deprecation/Puppet 8 compatibility issue tracked in #1391.

Related issues and PRs:

• The deprecation function and Puppet 8 are not compatible #1391: The deprecation function and Puppet 8 are not compatible
• Calls to Deprecation function cause catalog compilation to fail if strict setting is set to error #1373: Calls to Deprecation function cause catalog compilation to fail if strict setting is set to error
• Ignore Puppet's strict setting when calling function without namespace #1377: Ignore Puppet's strict setting when calling function without namespace
• Add use_strict_setting parameter to deprecation function #1378: Add use_strict_setting parameter to deprecation function

The previous fixes addressed namespaced/non-namespaced function shims, but validate_legacy() still has a direct deprecation() call and can still fail.

Affected Code

Current validate_legacy() calls deprecation() before doing the assertion:

def validate_legacy(_scope, target_type, _function_name, value, *_prev_args)
  call_function('deprecation', 'validate_legacy', 'This method is deprecated, please use Puppet data types to validate parameters')
  if assert_type(target_type, value)
    # "Silently" passes
  else
    inferred_type = Puppet::Pops::Types::TypeCalculator.infer_set(value)
    error_msg = Puppet::Pops::Types::TypeMismatchDescriber.new.describe_mismatch("validate_legacy(#{target_type}, ...)", target_type, inferred_type)
    call_function('fail', error_msg)
  end
end

Expected Behaviour

validate_legacy() should preserve its legacy compatibility behaviour:

• valid values should pass silently
• invalid values should fail with the existing type mismatch error
• the fact that validate_legacy() is deprecated should not itself make catalog compilation fail under Puppet 8

Actual Behaviour

The direct call to stdlib deprecation() can raise under Puppet 8 strict deprecation handling, so otherwise valid catalogs fail before validate_legacy() evaluates the supplied value.