Don't parse cli args on the global object in sphinxpolicygen3.0.2

sphinxpolicygen is calling the generate_sample cli entrypoint when
we aren't actually the command being run. This can cause problems
if the consuming project has cli args that get registered on import
of their modules because we may have parsed args before those modules
get imported. This results in an exception because oslo.config won't
allow cli args to be registered after they've been parsed once.

This change makes use of the existing parameter to generate_sample
that allows us to pass in a local config object on which to register
the cli args. This way we can parse them without affecting the
global config object.

This was the only place I could find that we were doing something
like this so I believe it should eliminate the problem.

Change-Id: I8e9f28b0a15d1ed092d72b983be74fe281708fbe

1 files changed, 8 insertions, 1 deletions

diff --git a/oslo_policy/sphinxpolicygen.py b/oslo_policy/sphinxpolicygen.py
index c6158c6..2693e34 100644
--- a/oslo_policy/sphinxpolicygen.py
+++ b/oslo_policy/sphinxpolicygen.py
@@ -17,6 +17,7 @@
 
 import os
 
+from oslo_config import cfg
 from sphinx.util import logging
 
 from oslo_policy import generator
@@ -77,8 +78,14 @@ def _generate_sample(app, policy_file, base_name):
         out_file = os.path.join(app.srcdir, file_name)
 
     info('writing sample policy to %s' % out_file)
+    # NOTE(bnemec): We don't want to do cli parsing on the global object here
+    # because that can break consumers who do cli arg registration on import
+    # in their documented modules. It's not allowed to register a cli arg after
+    # the args have been parsed once.
+    conf = cfg.ConfigOpts()
     generator.generate_sample(args=['--config-file', config_path,
-                                    '--output-file', out_file])
+                                    '--output-file', out_file],
+                              conf=conf)
 
 
 def setup(app):