From beeb6b5946fec1c01bc6f5c47d24e4318f86cf89 Mon Sep 17 00:00:00 2001
From: Daniel Sheppard <dans@dansheps.com>
Date: Tue, 15 Dec 2020 09:00:25 -0600
Subject: [PATCH] Fixes: #5450 - Change all *_count and count_* serializers to
 have default value

---
 docs/release-notes/version-2.10.md            |  1 +
 netbox/circuits/api/nested_serializers.py     |  4 +-
 netbox/circuits/api/serializers.py            |  4 +-
 netbox/dcim/api/nested_serializers.py         | 24 +++++-----
 netbox/dcim/api/serializers.py                | 44 +++++++++----------
 netbox/extras/api/serializers.py              |  2 +-
 netbox/ipam/api/nested_serializers.py         | 10 ++---
 netbox/ipam/api/serializers.py                | 14 +++---
 netbox/secrets/api/nested_serializers.py      |  2 +-
 netbox/secrets/api/serializers.py             |  2 +-
 netbox/tenancy/api/nested_serializers.py      |  2 +-
 netbox/tenancy/api/serializers.py             | 22 +++++-----
 netbox/users/api/serializers.py               |  2 +-
 .../virtualization/api/nested_serializers.py  |  6 +--
 netbox/virtualization/api/serializers.py      |  8 ++--
 15 files changed, 74 insertions(+), 73 deletions(-)

diff --git a/docs/release-notes/version-2.10.md b/docs/release-notes/version-2.10.md
index 7584d8eae..351f5462b 100644
--- a/docs/release-notes/version-2.10.md
+++ b/docs/release-notes/version-2.10.md
@@ -4,6 +4,7 @@
 
 ### Bug Fixes
 
+* [#5450](https://github.com/netbox-community/netbox/issues/5450) - API serializer foreign count fields do not have a default value
 * [#5458](https://github.com/netbox-community/netbox/issues/5458) - Creating a component template throws an exception
 * [#5461](https://github.com/netbox-community/netbox/issues/5461) - Rack Elevations throw reverse match exception
 
diff --git a/netbox/circuits/api/nested_serializers.py b/netbox/circuits/api/nested_serializers.py
index 2d3457d2c..e777247b9 100644
--- a/netbox/circuits/api/nested_serializers.py
+++ b/netbox/circuits/api/nested_serializers.py
@@ -17,7 +17,7 @@ __all__ = [
 
 class NestedProviderSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='circuits-api:provider-detail')
-    circuit_count = serializers.IntegerField(read_only=True)
+    circuit_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = Provider
@@ -30,7 +30,7 @@ class NestedProviderSerializer(WritableNestedSerializer):
 
 class NestedCircuitTypeSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='circuits-api:circuittype-detail')
-    circuit_count = serializers.IntegerField(read_only=True)
+    circuit_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = CircuitType
diff --git a/netbox/circuits/api/serializers.py b/netbox/circuits/api/serializers.py
index 88890bf95..6291a8ea8 100644
--- a/netbox/circuits/api/serializers.py
+++ b/netbox/circuits/api/serializers.py
@@ -17,7 +17,7 @@ from .nested_serializers import *
 
 class ProviderSerializer(TaggedObjectSerializer, CustomFieldModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='circuits-api:provider-detail')
-    circuit_count = serializers.IntegerField(read_only=True)
+    circuit_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = Provider
@@ -33,7 +33,7 @@ class ProviderSerializer(TaggedObjectSerializer, CustomFieldModelSerializer):
 
 class CircuitTypeSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='circuits-api:circuittype-detail')
-    circuit_count = serializers.IntegerField(read_only=True)
+    circuit_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = CircuitType
diff --git a/netbox/dcim/api/nested_serializers.py b/netbox/dcim/api/nested_serializers.py
index d63d32d68..23cb9b550 100644
--- a/netbox/dcim/api/nested_serializers.py
+++ b/netbox/dcim/api/nested_serializers.py
@@ -45,7 +45,7 @@ __all__ = [
 
 class NestedRegionSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:region-detail')
-    site_count = serializers.IntegerField(read_only=True)
+    site_count = serializers.IntegerField(read_only=True, default=0)
     _depth = serializers.IntegerField(source='level', read_only=True)
 
     class Meta:
@@ -67,7 +67,7 @@ class NestedSiteSerializer(WritableNestedSerializer):
 
 class NestedRackGroupSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:rackgroup-detail')
-    rack_count = serializers.IntegerField(read_only=True)
+    rack_count = serializers.IntegerField(read_only=True, default=0)
     _depth = serializers.IntegerField(source='level', read_only=True)
 
     class Meta:
@@ -77,7 +77,7 @@ class NestedRackGroupSerializer(WritableNestedSerializer):
 
 class NestedRackRoleSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:rackrole-detail')
-    rack_count = serializers.IntegerField(read_only=True)
+    rack_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = models.RackRole
@@ -86,7 +86,7 @@ class NestedRackRoleSerializer(WritableNestedSerializer):
 
 class NestedRackSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:rack-detail')
-    device_count = serializers.IntegerField(read_only=True)
+    device_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = models.Rack
@@ -111,7 +111,7 @@ class NestedRackReservationSerializer(WritableNestedSerializer):
 
 class NestedManufacturerSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:manufacturer-detail')
-    devicetype_count = serializers.IntegerField(read_only=True)
+    devicetype_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = models.Manufacturer
@@ -121,7 +121,7 @@ class NestedManufacturerSerializer(WritableNestedSerializer):
 class NestedDeviceTypeSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:devicetype-detail')
     manufacturer = NestedManufacturerSerializer(read_only=True)
-    device_count = serializers.IntegerField(read_only=True)
+    device_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = models.DeviceType
@@ -198,8 +198,8 @@ class NestedDeviceBayTemplateSerializer(WritableNestedSerializer):
 
 class NestedDeviceRoleSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:devicerole-detail')
-    device_count = serializers.IntegerField(read_only=True)
-    virtualmachine_count = serializers.IntegerField(read_only=True)
+    device_count = serializers.IntegerField(read_only=True, default=0)
+    virtualmachine_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = models.DeviceRole
@@ -208,8 +208,8 @@ class NestedDeviceRoleSerializer(WritableNestedSerializer):
 
 class NestedPlatformSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:platform-detail')
-    device_count = serializers.IntegerField(read_only=True)
-    virtualmachine_count = serializers.IntegerField(read_only=True)
+    device_count = serializers.IntegerField(read_only=True, default=0)
+    virtualmachine_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = models.Platform
@@ -325,7 +325,7 @@ class NestedCableSerializer(serializers.ModelSerializer):
 class NestedVirtualChassisSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:virtualchassis-detail')
     master = NestedDeviceSerializer()
-    member_count = serializers.IntegerField(read_only=True)
+    member_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = models.VirtualChassis
@@ -338,7 +338,7 @@ class NestedVirtualChassisSerializer(WritableNestedSerializer):
 
 class NestedPowerPanelSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:powerpanel-detail')
-    powerfeed_count = serializers.IntegerField(read_only=True)
+    powerfeed_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = models.PowerPanel
diff --git a/netbox/dcim/api/serializers.py b/netbox/dcim/api/serializers.py
index 6f497bfa6..3a6009148 100644
--- a/netbox/dcim/api/serializers.py
+++ b/netbox/dcim/api/serializers.py
@@ -85,7 +85,7 @@ class ConnectedEndpointSerializer(ValidatedModelSerializer):
 class RegionSerializer(serializers.ModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:region-detail')
     parent = NestedRegionSerializer(required=False, allow_null=True)
-    site_count = serializers.IntegerField(read_only=True)
+    site_count = serializers.IntegerField(read_only=True, default=0)
     _depth = serializers.IntegerField(source='level', read_only=True)
 
     class Meta:
@@ -99,12 +99,12 @@ class SiteSerializer(TaggedObjectSerializer, CustomFieldModelSerializer):
     region = NestedRegionSerializer(required=False, allow_null=True)
     tenant = NestedTenantSerializer(required=False, allow_null=True)
     time_zone = TimeZoneField(required=False)
-    circuit_count = serializers.IntegerField(read_only=True)
-    device_count = serializers.IntegerField(read_only=True)
-    prefix_count = serializers.IntegerField(read_only=True)
-    rack_count = serializers.IntegerField(read_only=True)
-    virtualmachine_count = serializers.IntegerField(read_only=True)
-    vlan_count = serializers.IntegerField(read_only=True)
+    circuit_count = serializers.IntegerField(read_only=True, default=0)
+    device_count = serializers.IntegerField(read_only=True, default=0)
+    prefix_count = serializers.IntegerField(read_only=True, default=0)
+    rack_count = serializers.IntegerField(read_only=True, default=0)
+    virtualmachine_count = serializers.IntegerField(read_only=True, default=0)
+    vlan_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = Site
@@ -124,7 +124,7 @@ class RackGroupSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:rackgroup-detail')
     site = NestedSiteSerializer()
     parent = NestedRackGroupSerializer(required=False, allow_null=True)
-    rack_count = serializers.IntegerField(read_only=True)
+    rack_count = serializers.IntegerField(read_only=True, default=0)
     _depth = serializers.IntegerField(source='level', read_only=True)
 
     class Meta:
@@ -134,7 +134,7 @@ class RackGroupSerializer(ValidatedModelSerializer):
 
 class RackRoleSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:rackrole-detail')
-    rack_count = serializers.IntegerField(read_only=True)
+    rack_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = RackRole
@@ -151,8 +151,8 @@ class RackSerializer(TaggedObjectSerializer, CustomFieldModelSerializer):
     type = ChoiceField(choices=RackTypeChoices, allow_blank=True, required=False)
     width = ChoiceField(choices=RackWidthChoices, required=False)
     outer_unit = ChoiceField(choices=RackDimensionUnitChoices, allow_blank=True, required=False)
-    device_count = serializers.IntegerField(read_only=True)
-    powerfeed_count = serializers.IntegerField(read_only=True)
+    device_count = serializers.IntegerField(read_only=True, default=0)
+    powerfeed_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = Rack
@@ -244,9 +244,9 @@ class RackElevationDetailFilterSerializer(serializers.Serializer):
 
 class ManufacturerSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:manufacturer-detail')
-    devicetype_count = serializers.IntegerField(read_only=True)
-    inventoryitem_count = serializers.IntegerField(read_only=True)
-    platform_count = serializers.IntegerField(read_only=True)
+    devicetype_count = serializers.IntegerField(read_only=True, default=0)
+    inventoryitem_count = serializers.IntegerField(read_only=True, default=0)
+    platform_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = Manufacturer
@@ -259,7 +259,7 @@ class DeviceTypeSerializer(TaggedObjectSerializer, CustomFieldModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:devicetype-detail')
     manufacturer = NestedManufacturerSerializer()
     subdevice_role = ChoiceField(choices=SubdeviceRoleChoices, allow_blank=True, required=False)
-    device_count = serializers.IntegerField(read_only=True)
+    device_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = DeviceType
@@ -380,8 +380,8 @@ class DeviceBayTemplateSerializer(ValidatedModelSerializer):
 
 class DeviceRoleSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:devicerole-detail')
-    device_count = serializers.IntegerField(read_only=True)
-    virtualmachine_count = serializers.IntegerField(read_only=True)
+    device_count = serializers.IntegerField(read_only=True, default=0)
+    virtualmachine_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = DeviceRole
@@ -393,8 +393,8 @@ class DeviceRoleSerializer(ValidatedModelSerializer):
 class PlatformSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:platform-detail')
     manufacturer = NestedManufacturerSerializer(required=False, allow_null=True)
-    device_count = serializers.IntegerField(read_only=True)
-    virtualmachine_count = serializers.IntegerField(read_only=True)
+    device_count = serializers.IntegerField(read_only=True, default=0)
+    virtualmachine_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = Platform
@@ -573,7 +573,7 @@ class InterfaceSerializer(TaggedObjectSerializer, CableTerminationSerializer, Co
         many=True
     )
     cable = NestedCableSerializer(read_only=True)
-    count_ipaddresses = serializers.IntegerField(read_only=True)
+    count_ipaddresses = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = Interface
@@ -805,7 +805,7 @@ class InterfaceConnectionSerializer(ValidatedModelSerializer):
 class VirtualChassisSerializer(TaggedObjectSerializer, CustomFieldModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='dcim-api:virtualchassis-detail')
     master = NestedDeviceSerializer(required=False)
-    member_count = serializers.IntegerField(read_only=True)
+    member_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = VirtualChassis
@@ -824,7 +824,7 @@ class PowerPanelSerializer(TaggedObjectSerializer, CustomFieldModelSerializer):
         allow_null=True,
         default=None
     )
-    powerfeed_count = serializers.IntegerField(read_only=True)
+    powerfeed_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = PowerPanel
diff --git a/netbox/extras/api/serializers.py b/netbox/extras/api/serializers.py
index a85ca05b7..4bc10f7d8 100644
--- a/netbox/extras/api/serializers.py
+++ b/netbox/extras/api/serializers.py
@@ -66,7 +66,7 @@ class ExportTemplateSerializer(ValidatedModelSerializer):
 
 class TagSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='extras-api:tag-detail')
-    tagged_items = serializers.IntegerField(read_only=True)
+    tagged_items = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = Tag
diff --git a/netbox/ipam/api/nested_serializers.py b/netbox/ipam/api/nested_serializers.py
index 660db2b22..1c3217ae0 100644
--- a/netbox/ipam/api/nested_serializers.py
+++ b/netbox/ipam/api/nested_serializers.py
@@ -23,7 +23,7 @@ __all__ = [
 
 class NestedVRFSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='ipam-api:vrf-detail')
-    prefix_count = serializers.IntegerField(read_only=True)
+    prefix_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = models.VRF
@@ -48,7 +48,7 @@ class NestedRouteTargetSerializer(WritableNestedSerializer):
 
 class NestedRIRSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='ipam-api:rir-detail')
-    aggregate_count = serializers.IntegerField(read_only=True)
+    aggregate_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = models.RIR
@@ -70,8 +70,8 @@ class NestedAggregateSerializer(WritableNestedSerializer):
 
 class NestedRoleSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='ipam-api:role-detail')
-    prefix_count = serializers.IntegerField(read_only=True)
-    vlan_count = serializers.IntegerField(read_only=True)
+    prefix_count = serializers.IntegerField(read_only=True, default=0)
+    vlan_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = models.Role
@@ -80,7 +80,7 @@ class NestedRoleSerializer(WritableNestedSerializer):
 
 class NestedVLANGroupSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='ipam-api:vlangroup-detail')
-    vlan_count = serializers.IntegerField(read_only=True)
+    vlan_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = models.VLANGroup
diff --git a/netbox/ipam/api/serializers.py b/netbox/ipam/api/serializers.py
index 7552ae0d2..e5c0e33a2 100644
--- a/netbox/ipam/api/serializers.py
+++ b/netbox/ipam/api/serializers.py
@@ -27,8 +27,8 @@ class VRFSerializer(TaggedObjectSerializer, CustomFieldModelSerializer):
     tenant = NestedTenantSerializer(required=False, allow_null=True)
     import_targets = NestedRouteTargetSerializer(required=False, allow_null=True, many=True)
     export_targets = NestedRouteTargetSerializer(required=False, allow_null=True, many=True)
-    ipaddress_count = serializers.IntegerField(read_only=True)
-    prefix_count = serializers.IntegerField(read_only=True)
+    ipaddress_count = serializers.IntegerField(read_only=True, default=0)
+    prefix_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = VRF
@@ -59,7 +59,7 @@ class RouteTargetSerializer(TaggedObjectSerializer, CustomFieldModelSerializer):
 
 class RIRSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='ipam-api:rir-detail')
-    aggregate_count = serializers.IntegerField(read_only=True)
+    aggregate_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = RIR
@@ -87,8 +87,8 @@ class AggregateSerializer(TaggedObjectSerializer, CustomFieldModelSerializer):
 
 class RoleSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='ipam-api:role-detail')
-    prefix_count = serializers.IntegerField(read_only=True)
-    vlan_count = serializers.IntegerField(read_only=True)
+    prefix_count = serializers.IntegerField(read_only=True, default=0)
+    vlan_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = Role
@@ -98,7 +98,7 @@ class RoleSerializer(ValidatedModelSerializer):
 class VLANGroupSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='ipam-api:vlangroup-detail')
     site = NestedSiteSerializer(required=False, allow_null=True)
-    vlan_count = serializers.IntegerField(read_only=True)
+    vlan_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = VLANGroup
@@ -126,7 +126,7 @@ class VLANSerializer(TaggedObjectSerializer, CustomFieldModelSerializer):
     tenant = NestedTenantSerializer(required=False, allow_null=True)
     status = ChoiceField(choices=VLANStatusChoices, required=False)
     role = NestedRoleSerializer(required=False, allow_null=True)
-    prefix_count = serializers.IntegerField(read_only=True)
+    prefix_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = VLAN
diff --git a/netbox/secrets/api/nested_serializers.py b/netbox/secrets/api/nested_serializers.py
index aaec27c1f..838100865 100644
--- a/netbox/secrets/api/nested_serializers.py
+++ b/netbox/secrets/api/nested_serializers.py
@@ -19,7 +19,7 @@ class NestedSecretSerializer(WritableNestedSerializer):
 
 class NestedSecretRoleSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='secrets-api:secretrole-detail')
-    secret_count = serializers.IntegerField(read_only=True)
+    secret_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = SecretRole
diff --git a/netbox/secrets/api/serializers.py b/netbox/secrets/api/serializers.py
index b08b87bc5..ba19bf207 100644
--- a/netbox/secrets/api/serializers.py
+++ b/netbox/secrets/api/serializers.py
@@ -17,7 +17,7 @@ from .nested_serializers import *
 
 class SecretRoleSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='secrets-api:secretrole-detail')
-    secret_count = serializers.IntegerField(read_only=True)
+    secret_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = SecretRole
diff --git a/netbox/tenancy/api/nested_serializers.py b/netbox/tenancy/api/nested_serializers.py
index 7b227c123..8bb78b6c5 100644
--- a/netbox/tenancy/api/nested_serializers.py
+++ b/netbox/tenancy/api/nested_serializers.py
@@ -15,7 +15,7 @@ __all__ = [
 
 class NestedTenantGroupSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='tenancy-api:tenantgroup-detail')
-    tenant_count = serializers.IntegerField(read_only=True)
+    tenant_count = serializers.IntegerField(read_only=True, default=0)
     _depth = serializers.IntegerField(source='level', read_only=True)
 
     class Meta:
diff --git a/netbox/tenancy/api/serializers.py b/netbox/tenancy/api/serializers.py
index 05e83853e..594fd8d50 100644
--- a/netbox/tenancy/api/serializers.py
+++ b/netbox/tenancy/api/serializers.py
@@ -14,7 +14,7 @@ from .nested_serializers import *
 class TenantGroupSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='tenancy-api:tenantgroup-detail')
     parent = NestedTenantGroupSerializer(required=False, allow_null=True)
-    tenant_count = serializers.IntegerField(read_only=True)
+    tenant_count = serializers.IntegerField(read_only=True, default=0)
     _depth = serializers.IntegerField(source='level', read_only=True)
 
     class Meta:
@@ -25,16 +25,16 @@ class TenantGroupSerializer(ValidatedModelSerializer):
 class TenantSerializer(TaggedObjectSerializer, CustomFieldModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='tenancy-api:tenant-detail')
     group = NestedTenantGroupSerializer(required=False)
-    circuit_count = serializers.IntegerField(read_only=True)
-    device_count = serializers.IntegerField(read_only=True)
-    ipaddress_count = serializers.IntegerField(read_only=True)
-    prefix_count = serializers.IntegerField(read_only=True)
-    rack_count = serializers.IntegerField(read_only=True)
-    site_count = serializers.IntegerField(read_only=True)
-    virtualmachine_count = serializers.IntegerField(read_only=True)
-    vlan_count = serializers.IntegerField(read_only=True)
-    vrf_count = serializers.IntegerField(read_only=True)
-    cluster_count = serializers.IntegerField(read_only=True)
+    circuit_count = serializers.IntegerField(read_only=True, default=0)
+    device_count = serializers.IntegerField(read_only=True, default=0)
+    ipaddress_count = serializers.IntegerField(read_only=True, default=0)
+    prefix_count = serializers.IntegerField(read_only=True, default=0)
+    rack_count = serializers.IntegerField(read_only=True, default=0)
+    site_count = serializers.IntegerField(read_only=True, default=0)
+    virtualmachine_count = serializers.IntegerField(read_only=True, default=0)
+    vlan_count = serializers.IntegerField(read_only=True, default=0)
+    vrf_count = serializers.IntegerField(read_only=True, default=0)
+    cluster_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = Tenant
diff --git a/netbox/users/api/serializers.py b/netbox/users/api/serializers.py
index eed0bd80e..a2eaa0c91 100644
--- a/netbox/users/api/serializers.py
+++ b/netbox/users/api/serializers.py
@@ -40,7 +40,7 @@ class UserSerializer(ValidatedModelSerializer):
 
 class GroupSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='users-api:group-detail')
-    user_count = serializers.IntegerField(read_only=True)
+    user_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = Group
diff --git a/netbox/virtualization/api/nested_serializers.py b/netbox/virtualization/api/nested_serializers.py
index 7763f0ef4..c86cbd3f5 100644
--- a/netbox/virtualization/api/nested_serializers.py
+++ b/netbox/virtualization/api/nested_serializers.py
@@ -19,7 +19,7 @@ __all__ = [
 
 class NestedClusterTypeSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='virtualization-api:clustertype-detail')
-    cluster_count = serializers.IntegerField(read_only=True)
+    cluster_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = ClusterType
@@ -28,7 +28,7 @@ class NestedClusterTypeSerializer(WritableNestedSerializer):
 
 class NestedClusterGroupSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='virtualization-api:clustergroup-detail')
-    cluster_count = serializers.IntegerField(read_only=True)
+    cluster_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = ClusterGroup
@@ -37,7 +37,7 @@ class NestedClusterGroupSerializer(WritableNestedSerializer):
 
 class NestedClusterSerializer(WritableNestedSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='virtualization-api:cluster-detail')
-    virtualmachine_count = serializers.IntegerField(read_only=True)
+    virtualmachine_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = Cluster
diff --git a/netbox/virtualization/api/serializers.py b/netbox/virtualization/api/serializers.py
index 518b7086c..8813c2644 100644
--- a/netbox/virtualization/api/serializers.py
+++ b/netbox/virtualization/api/serializers.py
@@ -20,7 +20,7 @@ from .nested_serializers import *
 
 class ClusterTypeSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='virtualization-api:clustertype-detail')
-    cluster_count = serializers.IntegerField(read_only=True)
+    cluster_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = ClusterType
@@ -29,7 +29,7 @@ class ClusterTypeSerializer(ValidatedModelSerializer):
 
 class ClusterGroupSerializer(ValidatedModelSerializer):
     url = serializers.HyperlinkedIdentityField(view_name='virtualization-api:clustergroup-detail')
-    cluster_count = serializers.IntegerField(read_only=True)
+    cluster_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = ClusterGroup
@@ -42,8 +42,8 @@ class ClusterSerializer(TaggedObjectSerializer, CustomFieldModelSerializer):
     group = NestedClusterGroupSerializer(required=False, allow_null=True)
     tenant = NestedTenantSerializer(required=False, allow_null=True)
     site = NestedSiteSerializer(required=False, allow_null=True)
-    device_count = serializers.IntegerField(read_only=True)
-    virtualmachine_count = serializers.IntegerField(read_only=True)
+    device_count = serializers.IntegerField(read_only=True, default=0)
+    virtualmachine_count = serializers.IntegerField(read_only=True, default=0)
 
     class Meta:
         model = Cluster