feat: add delete-segment-override experimental endpoint

api/api/urls/experiments.py

@@ -7,7 +7,11 @@
 
 from django.urls import path
 
-from features.feature_states.views import update_flag_v1, update_flag_v2
+from features.feature_states.views import (
+    delete_segment_override,
+    update_flag_v1,
+    update_flag_v2,
+)
 
 app_name = "experiments"
 
@@ -22,4 +26,9 @@
         update_flag_v2,
         name="update-flag-v2",
     ),
+    path(
+        "environments/<str:environment_key>/delete-segment-override/",
+        delete_segment_override,
+        name="delete-segment-override",
+    ),
 ]

api/features/feature_states/serializers.py

@@ -8,7 +8,11 @@
     FlagChangeSetV2,
     SegmentOverrideChangeSet,
 )
-from features.versioning.versioning_service import update_flag, update_flag_v2
+from features.versioning.versioning_service import (
+    delete_segment_override,
+    update_flag,
+    update_flag_v2,
+)
 from segments.models import Segment
 
 
@@ -188,3 +192,24 @@ def change_set_v2(self) -> FlagChangeSetV2:
     def save(self, **kwargs: object) -> None:
         feature = self.get_feature()
         update_flag_v2(self.environment, feature, self.change_set_v2)
+
+
+class SegmentIdentifierSerializer(serializers.Serializer):  # type: ignore[type-arg]
+    id = serializers.IntegerField(required=True)
+
+
+class DeleteSegmentOverrideSerializer(BaseFeatureUpdateSerializer):
+    feature = FeatureIdentifierSerializer(required=True)
+    segment = SegmentIdentifierSerializer(required=True)
+
+    def validate_segment(self, value: dict) -> dict:  # type: ignore[type-arg]
+        if value and value.get("id"):
+            self.validate_segment_id(value["id"])
+        return value
+
+    def save(self, **kwargs: object) -> None:
+        feature = self.get_feature()
+        segment_id = self.validated_data["segment"]["id"]
+        author = AuthorData.from_request(self.context["request"])
+
+        delete_segment_override(self.environment, feature, segment_id, author)

api/features/feature_states/views.py

@@ -10,7 +10,11 @@
 from environments.models import Environment
 
 from .permissions import EnvironmentUpdateFeatureStatePermission
-from .serializers import UpdateFlagSerializer, UpdateFlagV2Serializer
+from .serializers import (
+    DeleteSegmentOverrideSerializer,
+    UpdateFlagSerializer,
+    UpdateFlagV2Serializer,
+)
 
 
 def _check_workflow_not_enabled(environment: Environment) -> None:
@@ -145,3 +149,52 @@ def update_flag_v2(request: Request, environment_key: str) -> Response:
     serializer.save()
 
     return Response(status=status.HTTP_204_NO_CONTENT)
+
+
+@swagger_auto_schema(
+    method="post",
+    operation_summary="Delete segment override",
+    operation_description="""
+    **EXPERIMENTAL ENDPOINT** - Subject to change without notice.
+
+    Deletes a segment override for a feature in the given environment.
+
+    **Feature Identification:**
+    - Use `feature.name` OR `feature.id` (mutually exclusive)
+    - Feature must belong to the environment's project
+
+    **Segment Identification:**
+    - Use `segment.id` (required)
+
+    The segment override must exist for the given feature/environment combination.
+    Returns 400 if the segment override does not exist.
+    """,
+    manual_parameters=[
+        openapi.Parameter(
+            "environment_key",
+            openapi.IN_PATH,
+            description="The environment API key",
+            type=openapi.TYPE_STRING,
+            required=True,
+        )
+    ],
+    request_body=DeleteSegmentOverrideSerializer,
+    responses={
+        204: openapi.Response(description="Segment override deleted successfully")
+    },
+    tags=["experimental"],
+)  # type: ignore[misc]
+@api_view(http_method_names=["POST"])
+@permission_classes([IsAuthenticated, EnvironmentUpdateFeatureStatePermission])
+def delete_segment_override(request: Request, environment_key: str) -> Response:
+    environment = Environment.objects.get(api_key=environment_key)
+    _check_workflow_not_enabled(environment)
+
+    serializer = DeleteSegmentOverrideSerializer(
+        data=request.data,
+        context={"request": request, "environment": environment},
+    )
+    serializer.is_valid(raise_exception=True)
+    serializer.save()
+
+    return Response(status=status.HTTP_204_NO_CONTENT)

api/features/versioning/versioning_service.py

@@ -3,11 +3,13 @@
 from common.core.utils import using_database_replica
 from django.db.models import Prefetch, Q, QuerySet
 from django.utils import timezone
+from rest_framework.exceptions import NotFound
 
 from environments.models import Environment
 from features.feature_states.models import FeatureValueType
-from features.models import Feature, FeatureState, FeatureStateValue
+from features.models import Feature, FeatureSegment, FeatureState, FeatureStateValue
 from features.versioning.dataclasses import (
+    AuthorData,
     FlagChangeSet,
     FlagChangeSetV2,
 )
@@ -395,6 +397,64 @@ def _update_flag_v2_for_versioning_v1(
                 _update_segment_priority(segment_state, override.priority)
 
 
+def delete_segment_override(
+    environment: "Environment",
+    feature: "Feature",
+    segment_id: int,
+    author: AuthorData,
+) -> None:
+    if environment.use_v2_feature_versioning:
+        _delete_segment_override_v2(environment, feature, segment_id, author)
+    else:
+        _delete_segment_override_v1(environment, feature, segment_id)
+
+
+def _delete_segment_override_v1(
+    environment: "Environment",
+    feature: "Feature",
+    segment_id: int,
+) -> None:
+    deleted_count, _ = FeatureSegment.objects.filter(
+        feature=feature,
+        segment_id=segment_id,
+        environment=environment,
+    ).delete()
+    if deleted_count == 0:
+        raise NotFound(f"Segment override for segment {segment_id} does not exist")
+
+
+def _delete_segment_override_v2(
+    environment: "Environment",
+    feature: "Feature",
+    segment_id: int,
+    author: AuthorData,
+) -> None:
+    current_version = get_current_live_environment_feature_version(
+        environment.id, feature.id
+    )
+    if (
+        not current_version
+        or not current_version.feature_states.filter(
+            feature_segment__segment_id=segment_id
+        ).exists()
+    ):
+        raise NotFound(f"Segment override for segment {segment_id} does not exist")
+
+    new_version = EnvironmentFeatureVersion.objects.create(
+        environment=environment,
+        feature=feature,
+        created_by=author.user,
+        created_by_api_key=author.api_key,
+    )
+
+    segment_feature_state = new_version.feature_states.get(
+        feature_segment__segment_id=segment_id
+    )
+    segment_feature_state.feature_segment.delete()
+
+    new_version.publish(published_by=author.user, published_by_api_key=author.api_key)
+
+
 def get_updated_feature_states_for_version(
     version: EnvironmentFeatureVersion,
 ) -> list[FeatureState]: