Address code review feedback: fix imports and BuildConfig consistency

Co-authored-by: humitos <244656+humitos@users.noreply.github.com>

Author: Copilot

readthedocs/builds/models.py

@@ -863,10 +863,11 @@ def save(self, *args, **kwargs):  # noqa
             if previous is not None and self._config and self._config == previous.config:
                 previous_pk = previous._config.get(self.CONFIG_KEY, previous.pk)
                 self._config = {self.CONFIG_KEY: previous_pk}
-            
-            # Populate the new readthedocs_yaml_data field
-            # We only create a BuildConfig when we have actual config data (not a reference)
-            if self._config and self.CONFIG_KEY not in self._config:
+                # Clear readthedocs_yaml_data when using reference style
+                self.readthedocs_yaml_data = None
+            elif self._config and self.CONFIG_KEY not in self._config:
+                # Populate the new readthedocs_yaml_data field
+                # We only create a BuildConfig when we have actual config data (not a reference)
                 # Use get_or_create to avoid duplicates and leverage the unique constraint
                 build_config, created = BuildConfig.objects.get_or_create(
                     data=self._config

readthedocs/builds/tests/test_buildconfig.py

@@ -2,9 +2,11 @@
 
 import django_dynamic_fixture as fixture
 import pytest
+from django.db import IntegrityError
 
 from readthedocs.builds.models import Build
 from readthedocs.builds.models import BuildConfig
+from readthedocs.builds.models import Version
 from readthedocs.projects.models import Project
 
 
@@ -28,7 +30,6 @@ def test_buildconfig_unique_constraint(self):
         BuildConfig.objects.create(data=config_data)
 
         # Try to create another with the same data - should raise IntegrityError
-        from django.db import IntegrityError
         with pytest.raises(IntegrityError):
             BuildConfig.objects.create(data=config_data)
 
@@ -117,8 +118,6 @@ def test_build_without_config_does_not_create_buildconfig(self):
 
     def test_build_with_config_reference_uses_same_buildconfig(self):
         """Test that a Build with config reference (old style) doesn't create a new BuildConfig."""
-        from readthedocs.builds.models import Version
-        
         project = fixture.get(Project)
         version = fixture.get(Version, project=project)
         config_data = {"build": {"os": "ubuntu-22.04"}}