Suppress deprecation warnings in oslopolicy-list-redundant

When running the tool against a project with a lot of deprecated
policies, the deprecation warnings overwhelm the important output
from the tool. Since checking for deprecations isn't the purpose of
this tool, let's just suppress warnings and limit the output to the
list of redundant policy rules that the user cares about.

I will note that the suppress_deprecation_warnings member is marked
as test only, but that was targeted at consumers of oslo.policy
rather than oslo.policy itself. I could also argue that we're
"testing" for redundant policies here, but that feels like semantic
hair splitting. :-)

Change-Id: I194af14ebd341366dbb1dd033654739a7f3d085c
Partial-Bug: 1836568

oslo_policy/generator.py

@@ -315,6 +315,11 @@ def _list_redundant(namespace):
     in a policy file and operators should consider removing them.
     """
     enforcer = _get_enforcer(namespace)
+    # NOTE(bnemec): We don't want to see policy deprecation warnings in the
+    # output of this tool. They tend to overwhelm the output that the user
+    # actually cares about, and checking for deprecations isn't the purpose of
+    # this tool.
+    enforcer.suppress_deprecation_warnings = True
     # Ensure that files have been parsed
     enforcer.load_rules()
 

oslo_policy/tests/test_generator.py

@@ -564,7 +564,8 @@ class ListRedundantTestCase(base.PolicyBaseTestCase):
     def setUp(self):
         super(ListRedundantTestCase, self).setUp()
 
-    def test_matched_rules(self):
+    @mock.patch('warnings.warn')
+    def test_matched_rules(self, mock_warn):
         extensions = []
         for name, opts in OPTS.items():
             ext = stevedore.extension.Extension(name=name, entry_point=None,
@@ -587,7 +588,13 @@ class ListRedundantTestCase(base.PolicyBaseTestCase):
         enforcer.register_default(
             policy.RuleDefault('owner', 'project_id:%(project_id)s'))
         # register a new opt
-        enforcer.register_default(policy.RuleDefault('foo', 'role:foo'))
+        deprecated_rule = policy.DeprecatedRule('old_foo', 'role:bar')
+        enforcer.register_default(
+            policy.RuleDefault('foo', 'role:foo',
+                               deprecated_rule=deprecated_rule,
+                               deprecated_reason='reason',
+                               deprecated_since='T')
+            )
 
         # Mock out stevedore to return the configured enforcer
         ext = stevedore.extension.Extension(name='testing', entry_point=None,
@@ -618,6 +625,9 @@ class ListRedundantTestCase(base.PolicyBaseTestCase):
         self.assertEqual('"owner"', opt1[0])
         self.assertEqual('"project_id:%(project_id)s"', opt1[1])
 
+        self.assertFalse(mock_warn.called,
+                         'Deprecation warnings not suppressed.')
+
 
 class UpgradePolicyTestCase(base.PolicyBaseTestCase):
     def setUp(self):

releasenotes/notes/list-redundant-deprecation-warnings-f84a06133efdaedd.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Deprecated policy warnings are now suppressed in the
+    ``oslopolicy-list-redundant`` tool so that they don't overwhelm the
+    relevant output.