Refactor obj_make_compatible to reduce complexity

Our tox.ini sets the maximum complexity of a function to be 40. Adding
anything new to the ImageMetaProps.obj_make_compatible push it over the
limit. So this patch factors out common new field value checking logic
to a helper function to reduce the complexity before adding new supported
values.

As there was a small amount of this check in other ovos this patch does
the refactor across all nova ovos.

Change-Id: I828d91196ea06f4dc2823218f036960123446255

nova/objects/base.py

@@ -26,6 +26,7 @@ from oslo_utils import versionutils
 from oslo_versionedobjects import base as ovoo_base
 from oslo_versionedobjects import exception as ovoo_exc
 
+from nova import exception
 from nova import objects
 from nova.objects import fields as obj_fields
 from nova import utils
@@ -58,6 +59,15 @@ def get_attrname(name):
     return '_obj_' + name
 
 
+def raise_on_too_new_values(version, primitive, field, new_values):
+    value = primitive.get(field, None)
+    if value in new_values:
+        raise exception.ObjectActionError(
+            action='obj_make_compatible',
+            reason='%s=%s not supported in version %s' %
+                   (field, value, version))
+
+
 class NovaObjectRegistry(ovoo_base.VersionedObjectRegistry):
     notification_classes = []
 

nova/objects/image_meta.py

@@ -16,7 +16,6 @@ import copy
 
 from oslo_utils import versionutils
 
-from nova import exception
 from nova import objects
 from nova.objects import base
 from nova.objects import fields
@@ -224,32 +223,23 @@ class ImageMetaProps(base.NovaObject):
         if target_version < (1, 31):
             primitive.pop('hw_emulation_architecture', None)
         if target_version < (1, 30):
-            video = primitive.get('hw_video_model', None)
-            if video == fields.VideoModel.BOCHS:
-                raise exception.ObjectActionError(
-                    action='obj_make_compatible',
-                    reason='hw_video_model=%s not supported in version %s' %
-                           (video, target_version))
+            base.raise_on_too_new_values(
+                target_version, primitive,
+                'hw_video_model', (fields.VideoModel.BOCHS,))
         if target_version < (1, 29):
             primitive.pop('hw_input_bus', None)
         if target_version < (1, 28):
-            policy = primitive.get('hw_pci_numa_affinity_policy', None)
-            if policy == fields.PCINUMAAffinityPolicy.SOCKET:
-                raise exception.ObjectActionError(
-                    action='obj_make_compatible',
-                    reason='hw_numa_affinity_policy=%s not supported '
-                           'in version %s' %
-                           (policy, target_version))
+            base.raise_on_too_new_values(
+                target_version, primitive,
+                'hw_pci_numa_affinity_policy',
+                (fields.PCINUMAAffinityPolicy.SOCKET,))
         if target_version < (1, 27):
             primitive.pop('hw_tpm_model', None)
             primitive.pop('hw_tpm_version', None)
         if target_version < (1, 26):
-            policy = primitive.get('hw_cpu_policy', None)
-            if policy == fields.CPUAllocationPolicy.MIXED:
-                raise exception.ObjectActionError(
-                    action='obj_make_compatible',
-                    reason='hw_cpu_policy=%s not supported in version %s' %
-                           (policy, target_version))
+            base.raise_on_too_new_values(
+                target_version, primitive,
+                'hw_cpu_policy', (fields.CPUAllocationPolicy.MIXED,))
         if target_version < (1, 25):
             primitive.pop('hw_pci_numa_affinity_policy', None)
         if target_version < (1, 24):
@@ -259,12 +249,12 @@ class ImageMetaProps(base.NovaObject):
         # NOTE(sean-k-mooney): unlike other nova object we version this object
         # when composed object are updated.
         if target_version < (1, 22):
-            video = primitive.get('hw_video_model', None)
-            if video in ('gop', 'virtio', 'none'):
-                raise exception.ObjectActionError(
-                    action='obj_make_compatible',
-                    reason='hw_video_model=%s not supported in version %s' % (
-                        video, target_version))
+            base.raise_on_too_new_values(
+                target_version, primitive,
+                'hw_video_model',
+                (fields.VideoModel.GOP,
+                 fields.VideoModel.VIRTIO,
+                 fields.VideoModel.NONE))
         if target_version < (1, 21):
             primitive.pop('hw_time_hpet', None)
         if target_version < (1, 20):
@@ -303,12 +293,9 @@ class ImageMetaProps(base.NovaObject):
             primitive.pop('os_require_quiesce', None)
 
         if target_version < (1, 6):
-            bus = primitive.get('hw_disk_bus', None)
-            if bus in ('lxc', 'uml'):
-                raise exception.ObjectActionError(
-                    action='obj_make_compatible',
-                    reason='hw_disk_bus=%s not supported in version %s' % (
-                        bus, target_version))
+            base.raise_on_too_new_values(
+                target_version, primitive,
+                'hw_disk_bus', (fields.DiskBus.LXC, fields.DiskBus.UML))
 
     # Maximum number of NUMA nodes permitted for the guest topology
     NUMA_NODES_MAX = 128

nova/objects/instance_numa.py

@@ -20,7 +20,6 @@ from oslo_utils import versionutils
 
 from nova.db.main import api as db
 from nova import exception
-from nova.i18n import _
 from nova.objects import base
 from nova.objects import fields as obj_fields
 from nova.virt import hardware
@@ -48,15 +47,9 @@ class InstanceNUMACell(base.NovaEphemeralObject,
         # Instance with a 'mixed' CPU policy could not provide a backward
         # compatibility.
         if target_version < (1, 6):
-            if primitive['cpu_policy'] == obj_fields.CPUAllocationPolicy.MIXED:
-                raise exception.ObjectActionError(
-                    action='obj_make_compatible',
-                    reason=_(
-                        '{policy} policy is not supported in '
-                        'version {version}'
-                    ).format(policy=primitive['cpu_policy'],
-                             version=target_version))
-
+            base.raise_on_too_new_values(
+                target_version, primitive,
+                'cpu_policy', (obj_fields.CPUAllocationPolicy.MIXED,))
         # NOTE(huaqiang): Since version 1.5, 'cpuset' is modified to track the
         # unpinned CPUs only, with pinned CPUs tracked via 'pcpuset' instead.
         # For a backward compatibility, move the 'dedicated' instance CPU list

nova/objects/pci_device.py

@@ -132,21 +132,14 @@ class PciDevice(base.NovaPersistentObject, base.NovaObject):
         if target_version < (1, 5) and 'parent_addr' in primitive:
             added_statuses = (fields.PciDeviceStatus.UNCLAIMABLE,
                               fields.PciDeviceStatus.UNAVAILABLE)
-            status = primitive['status']
-            if status in added_statuses:
-                raise exception.ObjectActionError(
-                    action='obj_make_compatible',
-                    reason='status=%s not supported in version %s' % (
-                        status, target_version))
+            base.raise_on_too_new_values(
+                target_version, primitive, 'status', added_statuses)
         if target_version < (1, 6) and 'uuid' in primitive:
             del primitive['uuid']
         if target_version < (1, 7) and 'dev_type' in primitive:
-            dev_type = primitive['dev_type']
-            if dev_type == fields.PciDeviceType.VDPA:
-                raise exception.ObjectActionError(
-                    action='obj_make_compatible',
-                    reason='dev_type=%s not supported in version %s' % (
-                        dev_type, target_version))
+            base.raise_on_too_new_values(
+                target_version, primitive,
+                'dev_type', (fields.PciDeviceType.VDPA,))
 
     def __repr__(self):
         return (