adapters: fix compat for auto accessors

The keystone interface rebase to the Endpoint base class re-uses
the auto_accessors approach from RelationBase which makes the
interface smell a little different to other Endpoint based interfaces.

Check and map any keys listed in auto_accessors for all relation
class types rather than just for RelationBase.

This also fixes a minor issue where self.accessors was reset to []
when the auto_accessors attribute was not found in the relation
overwriting any accessors passed in during object construction.

Change-Id: I4481c6d8ad5c9f0a8bc5e892d1d7472be83f3454

charms_openstack/adapters.py

@@ -187,23 +187,22 @@ class OpenStackRelationAdapter(object):
                         (lambda name: property(
                             lambda self: getattr(
                                 self.relation, name)))(name))
-        else:
-            try:
-                self.accessors.extend(self.relation.auto_accessors)
-            except AttributeError:
-                self.accessors = []
-            for field in self.accessors:
-                meth_name = field.replace('-', '_')
-                # Get the relation property dynamically
-                # Note the additional lambda name: is to create a closure over
-                # meth_name so that a new 'name' gets created for each loop,
-                # otherwise the same variable meth_name is referenced in each
-                # of the internal lambdas.  i.e. this is (lambda x: ...)(value)
-                setattr(self.__class__,
-                        meth_name,
-                        (lambda name: property(
-                            lambda self: getattr(
-                                self.relation, name)()))(meth_name))
+        try:
+            self.accessors.extend(self.relation.auto_accessors)
+        except AttributeError:
+            pass
+        for field in self.accessors:
+            meth_name = field.replace('-', '_')
+            # Get the relation property dynamically
+            # Note the additional lambda name: is to create a closure over
+            # meth_name so that a new 'name' gets created for each loop,
+            # otherwise the same variable meth_name is referenced in each
+            # of the internal lambdas.  i.e. this is (lambda x: ...)(value)
+            setattr(self.__class__,
+                    meth_name,
+                    (lambda name: property(
+                        lambda self: getattr(
+                            self.relation, name)()))(meth_name))
 
 
 class MemcacheRelationAdapter(OpenStackRelationAdapter):

tox.ini

@@ -30,6 +30,10 @@ deps = -r{toxinidir}/test-requirements.txt
 basepython = python3.8
 deps = -r{toxinidir}/test-requirements.txt
 
+[testenv:py310]
+basepython = python3.10
+deps = -r{toxinidir}/test-requirements.txt
+
 [testenv:pep8]
 basepython = python3
 deps = -r{toxinidir}/test-requirements.txt

unit_tests/test_charms_openstack_adapters.py

@@ -136,6 +136,16 @@ class MyEndpointRelation(reactive.Endpoint):
         return self.value
 
 
+class MyEndpointAutoAccessorsRelation(
+        MyEndpointRelation,
+        metaclass=reactive.relations.AutoAccessors):
+
+    auto_accessors = ['foo', 'bar']
+
+    def get_remote(self, key):
+        return key
+
+
 class TestOpenStackRelationAdapter(unittest.TestCase):
 
     def test_class(self):
@@ -184,6 +194,17 @@ class TestOpenStackRelationAdapter(unittest.TestCase):
         with self.assertRaises(AttributeError):
             self.assertFalse(ad.a_function)
 
+    def test_class_with_endpoint_auto_accessors_relation(self):
+        er = MyEndpointAutoAccessorsRelation('my-name')
+        ad = adapters.OpenStackRelationAdapter(er)
+        self.assertEqual(ad.a_property, 'has value in config rendering')
+        er.value = 'can change after instantiation'
+        self.assertEqual(ad.a_property, 'can change after instantiation')
+        with self.assertRaises(AttributeError):
+            self.assertFalse(ad.a_function)
+        self.assertEqual(ad.foo, 'foo')
+        self.assertEqual(ad.bar, 'bar')
+
 
 class FakeMemcacheRelation():