system_hostname fails when no static_hosts specified

[bleything]

system_hostname 'test1.ops.sea.example.com'

... will fail with the following stacktrace:

/var/chef/cache/cookbooks/system/providers/hostname.rb:199:in `block in class_from_file'
(eval):2:in `block in action_set'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/provider.rb:211:in `instance_eval'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/provider.rb:211:in `compile_and_converge_action'
(eval):2:in `action_set'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/provider.rb:171:in `run_action'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/resource.rb:591:in `run_action'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/runner.rb:70:in `run_action'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/runner.rb:98:in `block (2 levels) in converge'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/runner.rb:98:in `each'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/runner.rb:98:in `block in converge'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/resource_collection/resource_list.rb:94:in `block in execute_each_resource'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/resource_collection/stepable_iterator.rb:114:in `call_iterator_block'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/resource_collection/stepable_iterator.rb:85:in `step'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/resource_collection/stepable_iterator.rb:103:in `iterate'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/resource_collection/stepable_iterator.rb:55:in `each_with_index'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/resource_collection/resource_list.rb:92:in `execute_each_resource'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/runner.rb:97:in `converge'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/client.rb:715:in `block in converge'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/client.rb:710:in `catch'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/client.rb:710:in `converge'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/client.rb:749:in `converge_and_save'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/client.rb:286:in `run'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/application.rb:291:in `block in fork_chef_client'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/application.rb:279:in `fork'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/application.rb:279:in `fork_chef_client'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/application.rb:244:in `block in run_chef_client'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/local_mode.rb:44:in `with_server_connectivity'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/application.rb:232:in `run_chef_client'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/application/client.rb:464:in `sleep_then_run_chef_client'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/application/client.rb:451:in `block in interval_run_chef_client'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/application/client.rb:450:in `loop'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/application/client.rb:450:in `interval_run_chef_client'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/application/client.rb:434:in `run_application'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/lib/chef/application.rb:59:in `run'
/opt/chef/embedded/lib/ruby/gems/2.4.0/gems/chef-13.1.31/bin/chef-client:26:in `<top (required)>'
/usr/bin/chef-client:58:in `load'
/usr/bin/chef-client:58:in `<main>'

... which points to this block.

I think that adding a default value to that attribute in the resource ought to do the trick... but that brings up a second issue, which is that the docs say that attribute expects an array of hashes, but the attribute itself and the provider which uses it both expect a hash.

[flaccid]

@bleything can you paste the whole output of the run?

[flaccid]

bc3b179 should help iterate over an empty hash instead of nil.