Fixes #3831: Fix API-driven filter field rendering (#3812 regression)

docs/release-notes/version-2.6.md

@@ -1,3 +1,11 @@
+# v2.6.11 (FUTURE)
+
+## Bug Fixes
+
+* [#3831](https://github.com/netbox-community/netbox/issues/3831) - Fix API-driven filter field rendering (#3812 regression)
+
+---
+
 # v2.6.10 (2020-01-02)
 
 ## Enhancements

netbox/circuits/forms.py

@@ -302,6 +302,9 @@ class CircuitFilterForm(BootstrapMixin, TenancyFilterForm, CustomFieldFilterForm
         widget=APISelectMultiple(
             api_url="/api/dcim/regions/",
             value_field="slug",
+            filter_for={
+                'site': 'region'
+            }
         )
     )
     site = FilterChoiceField(

netbox/dcim/forms.py

@@ -651,16 +651,15 @@ class RackFilterForm(BootstrapMixin, TenancyFilterForm, CustomFieldFilterForm):
             }
         )
     )
-    group_id = ChainedModelChoiceField(
-        label='Rack group',
-        queryset=RackGroup.objects.prefetch_related('site'),
-        chains=(
-            ('site', 'site'),
+    group_id = FilterChoiceField(
+        queryset=RackGroup.objects.prefetch_related(
+            'site'
         ),
-        required=False,
+        label='Rack group',
+        null_label='-- None --',
         widget=APISelectMultiple(
             api_url="/api/dcim/rack-groups/",
-            null_option=True,
+            null_option=True
         )
     )
     status = forms.MultipleChoiceField(

netbox/utilities/templates/widgets/select_api.html

@@ -1,5 +1,9 @@
-<select name="{{ widget.name }}"{% include "django/forms/widgets/attrs.html" %}>{% for group_name, group_choices, group_index in widget.optgroups %}{% if group_name %}
-  <optgroup label="{{ group_name }}">{% endif %}{% for widget in group_choices %}{% if widget.attrs.selected %}
-  {% include widget.template_name %}{% endif %}{% endfor %}{% if group_name %}
-  </optgroup>{% endif %}{% endfor %}
+<select name="{{ widget.name }}"{% include "django/forms/widgets/attrs.html" %}>
+{% for group_name, group_choices, group_index in widget.optgroups %}
+  {% if group_name %}<optgroup label="{{ group_name }}">{% endif %}
+  {% for option in group_choices %}
+    {% if option.attrs.selected or option.value == "null" %}{% include option.template_name with widget=option %}{% endif %}
+  {% endfor %}
+  {% if group_name %}</optgroup>{% endif %}
+{% endfor %}
 </select>

netbox/virtualization/forms.py

@@ -563,7 +563,9 @@ class VirtualMachineFilterForm(BootstrapMixin, TenancyFilterForm, CustomFieldFil
         widget=APISelectMultiple(
             api_url='/api/dcim/regions/',
             value_field="slug",
-            null_option=True,
+            filter_for={
+                'site': 'region'
+            }
         )
     )
     site = FilterChoiceField(