Fixes #4525: Allow passing initial data to custom script MultiObjectVar

docs/release-notes/version-2.8.md

@@ -15,6 +15,7 @@
 ### Bug Fixes
 
 * [#3304](https://github.com/netbox-community/netbox/issues/3304) - Fix caching invalidation issue related to device/virtual machine primary IP addresses
+* [#4525](https://github.com/netbox-community/netbox/issues/4525) - Allow passing initial data to custom script MultiObjectVar
 * [#4644](https://github.com/netbox-community/netbox/issues/4644) - Fix ordering of services table by parent
 * [#4646](https://github.com/netbox-community/netbox/issues/4646) - Correct UI link for reports with custom name
 * [#4647](https://github.com/netbox-community/netbox/issues/4647) - Fix caching invalidation issue related to assigning new IP addresses to interfaces

netbox/extras/forms.py

@@ -432,11 +432,11 @@ class ScriptForm(BootstrapMixin, forms.Form):
 
     def __init__(self, vars, *args, commit_default=True, **kwargs):
 
-        super().__init__(*args, **kwargs)
-
         # Dynamically populate fields for variables
         for name, var in vars.items():
-            self.fields[name] = var.as_field()
+            self.base_fields[name] = var.as_field()
+
+        super().__init__(*args, **kwargs)
 
         # Toggle default commit behavior based on Meta option
         if not commit_default:

netbox/utilities/forms.py

@@ -606,15 +606,18 @@ class DynamicModelChoiceMixin:
     filter = django_filters.ModelChoiceFilter
     widget = APISelect
 
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
+    def _get_initial_value(self, initial_data, field_name):
+        return initial_data.get(field_name)
 
     def get_bound_field(self, form, field_name):
         bound_field = BoundField(form, self, field_name)
 
+        # Override initial() to allow passing multiple values
+        bound_field.initial = self._get_initial_value(form.initial, field_name)
+
         # Modify the QuerySet of the field before we return it. Limit choices to any data already bound: Options
         # will be populated on-demand via the APISelect widget.
-        data = self.prepare_value(bound_field.data or bound_field.initial)
+        data = bound_field.value()
         if data:
             filter = self.filter(field_name=self.to_field_name or 'pk', queryset=self.queryset)
             self.queryset = filter.filter(self.queryset, data)
@@ -647,6 +650,12 @@ class DynamicModelMultipleChoiceField(DynamicModelChoiceMixin, forms.ModelMultip
     filter = django_filters.ModelMultipleChoiceFilter
     widget = APISelectMultiple
 
+    def _get_initial_value(self, initial_data, field_name):
+        # If a QueryDict has been passed as initial form data, get *all* listed values
+        if hasattr(initial_data, 'getlist'):
+            return initial_data.getlist(field_name)
+        return initial_data.get(field_name)
+
 
 class LaxURLField(forms.URLField):
     """