Fix RelatedField rendering wrong domain in hrefs

(cherry picked from commit 816a633)

Author: jobselko

CHANGES/7835.bugfix

@@ -0,0 +1 @@
+Fixed `RelatedField` rendering wrong domain in hrefs when `DOMAIN_ENABLED=True`.

pulpcore/app/serializers/base.py

@@ -65,6 +65,16 @@ def _patched_reverse(viewname, request=None, args=None, kwargs=None, **extra):
 class HrefPrnFieldMixin:
     """A mixin to configure related fields to generate relative hrefs and accept PRNs."""
 
+    def use_pk_only_optimization(self):
+        """Disable DRF's PK-only optimization when domains are enabled.
+
+        DRF's optimization passes a PKOnlyObject (no pulp_domain) to get_url,
+        causing _reverse to fall back to the default domain.
+        """
+        if settings.DOMAIN_ENABLED:
+            return False
+        return super().use_pk_only_optimization()
+
     def get_url(self, obj, view_name, request, *args, **kwargs):
         # Use the Pulp reverse method to display relative hrefs.
         self.reverse = _reverse(obj)