Allow deprecated decorator to specify no plan for removal

Allow the @deprecated decorator to specify functionality as deprecated
but not slate any release for removal of the deprecated functionality.

Change-Id: Iff24553ec83c4a8b0faf4b6381b6fe1589a1c089

openstack/common/versionutils.py

@@ -53,6 +53,14 @@ class deprecated(object):
     >>> @deprecated(as_of=deprecated.ICEHOUSE, remove_in=+1)
     ... def c(): pass
 
+    4. Specifying the deprecated functionality will not be removed:
+    >>> @deprecated(as_of=deprecated.ICEHOUSE, remove_in=0)
+    ... def d(): pass
+
+    5. Specifying a replacement, deprecated functionality will not be removed:
+    >>> @deprecated(as_of=deprecated.ICEHOUSE, in_favor_of='f()', remove_in=0)
+    ... def e(): pass
+
     """
 
     # NOTE(morganfainberg): Bexar is used for unit test purposes, it is
@@ -83,6 +91,12 @@ class deprecated(object):
         '%(what)s is deprecated as of %(as_of)s and may be '
         'removed in %(remove_in)s. It will not be superseded.')
 
+    _deprecated_msg_with_alternative_no_removal = _(
+        '%(what)s is deprecated as of %(as_of)s in favor of %(in_favor_of)s.')
+
+    _deprecated_msg_with_no_alternative_no_removal = _(
+        '%(what)s is deprecated as of %(as_of)s. It will not be superseded.')
+
     def __init__(self, as_of, in_favor_of=None, remove_in=2, what=None):
         """Initialize decorator
 
@@ -128,9 +142,19 @@ class deprecated(object):
 
         if self.in_favor_of:
             details['in_favor_of'] = self.in_favor_of
-            msg = self._deprecated_msg_with_alternative
+            if self.remove_in > 0:
+                msg = self._deprecated_msg_with_alternative
+            else:
+                # There are no plans to remove this function, but it is
+                # now deprecated.
+                msg = self._deprecated_msg_with_alternative_no_removal
         else:
-            msg = self._deprecated_msg_no_alternative
+            if self.remove_in > 0:
+                msg = self._deprecated_msg_no_alternative
+            else:
+                # There are no plans to remove this function, but it is
+                # now deprecated.
+                msg = self._deprecated_msg_with_no_alternative_no_removal
         return msg, details
 
 

tests/unit/test_versionutils.py

@@ -21,12 +21,23 @@ from openstack.common import versionutils
 
 
 class DeprecatedTestCase(test_base.BaseTestCase):
-    def assert_deprecated(self, mock_log, **expected_details):
+    def assert_deprecated(self, mock_log, no_removal=False,
+                          **expected_details):
         decorator = versionutils.deprecated
         if 'in_favor_of' in expected_details:
-            expected_msg = decorator._deprecated_msg_with_alternative
+            if no_removal is False:
+                expected_msg = decorator._deprecated_msg_with_alternative
+            else:
+                expected_msg = getattr(
+                    decorator,
+                    '_deprecated_msg_with_alternative_no_removal')
         else:
-            expected_msg = decorator._deprecated_msg_no_alternative
+            if no_removal is False:
+                expected_msg = decorator._deprecated_msg_no_alternative
+            else:
+                expected_msg = getattr(
+                    decorator,
+                    '_deprecated_msg_with_no_alternative_no_removal')
         mock_log.deprecated.assert_called_with(expected_msg, expected_details)
 
     @mock.patch('openstack.common.versionutils.LOG', mock.Mock())
@@ -146,6 +157,36 @@ class DeprecatedTestCase(test_base.BaseTestCase):
                                as_of='Grizzly',
                                remove_in='Juno')
 
+    @mock.patch('openstack.common.versionutils.LOG')
+    def test_deprecated_with_removed_zero(self, mock_log):
+        @versionutils.deprecated(as_of=versionutils.deprecated.GRIZZLY,
+                                 remove_in=0)
+        def do_outdated_stuff():
+            return
+
+        do_outdated_stuff()
+        self.assert_deprecated(mock_log,
+                               no_removal=True,
+                               what='do_outdated_stuff()',
+                               as_of='Grizzly',
+                               remove_in='Grizzly')
+
+    @mock.patch('openstack.common.versionutils.LOG')
+    def test_deprecated_with_removed_zero_and_alternative(self, mock_log):
+        @versionutils.deprecated(as_of=versionutils.deprecated.GRIZZLY,
+                                 in_favor_of='different_stuff()',
+                                 remove_in=0)
+        def do_outdated_stuff():
+            return
+
+        do_outdated_stuff()
+        self.assert_deprecated(mock_log,
+                               no_removal=True,
+                               what='do_outdated_stuff()',
+                               as_of='Grizzly',
+                               in_favor_of='different_stuff()',
+                               remove_in='Grizzly')
+
 
 class IsCompatibleTestCase(test_base.BaseTestCase):
     def test_same_version(self):