feat(api): add discriminators to link iface, appliance version and template settings schemas

tests/api/routes/controller/test_appliances.py

@@ -101,3 +101,33 @@ class TestApplianceRoutes:
             app.url_path_for("add_appliance_version", appliance_id=appliance_id), json=new_version
         )
         assert response.status_code == status.HTTP_409_CONFLICT
+
+    async def test_add_v8_version_appliance(self, app: FastAPI, client: AsyncClient) -> None:
+
+        appliance_id = "1cfdf900-7c30-4cb7-8f03-3f61d2581633"  # Empty VM appliance
+        new_version = {"name": "v8-99G", "category": "guest", "images": {"hda_disk_image": "empty99G.qcow2"}}
+        response = await client.post(
+            app.url_path_for("add_appliance_version", appliance_id=appliance_id), json=new_version
+        )
+        assert response.status_code == status.HTTP_201_CREATED
+        assert new_version in response.json()["versions"]
+
+    async def test_add_version_appliance_with_registry_version(self, app: FastAPI, client: AsyncClient) -> None:
+
+        appliance_id = "1cfdf900-7c30-4cb7-8f03-3f61d2581633"  # Empty VM appliance
+        stored_version = {"name": "explicit-99G", "images": {"hda_disk_image": "empty99G.qcow2"}}
+        response = await client.post(
+            app.url_path_for("add_appliance_version", appliance_id=appliance_id),
+            json=dict(stored_version, registry_version=3),
+        )
+        assert response.status_code == status.HTTP_201_CREATED
+        assert stored_version in response.json()["versions"]
+
+    async def test_add_version_appliance_unknown_registry_version(self, app: FastAPI, client: AsyncClient) -> None:
+
+        appliance_id = "1cfdf900-7c30-4cb7-8f03-3f61d2581633"  # Empty VM appliance
+        response = await client.post(
+            app.url_path_for("add_appliance_version", appliance_id=appliance_id),
+            json={"name": "bad", "registry_version": 7, "images": {"hda_disk_image": "empty99G.qcow2"}},
+        )
+        assert response.status_code == status.HTTP_422_UNPROCESSABLE_ENTITY

tests/api/routes/controller/test_links.py

@@ -376,6 +376,7 @@ class TestLinkRoutes:
         assert result["rhost"] == "127.0.0.1"
         assert result["rport"] == 30000
         assert result["type"] == "udp"
+        assert result["kind"] == "udp"
 
     async def test_get_ethernet_interface(self, app: FastAPI, client: AsyncClient, project: Project) -> None:
         """
@@ -406,3 +407,4 @@ class TestLinkRoutes:
         assert result["node_id"] == cloud_node.id
         assert result["interface"] == "eth0"
         assert result["type"] == "ethernet"
+        assert result["kind"] == "ethernet"

tests/api/test_openapi_discriminators.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2026 GNS3 Technologies Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import pytest
+from fastapi import FastAPI
+
+pytestmark = pytest.mark.asyncio
+
+
+@pytest.fixture
+def openapi(app: FastAPI) -> dict:
+    return app.openapi()
+
+
+def _ref(name: str) -> str:
+    return f"#/components/schemas/{name}"
+
+
+def _assert_discriminated(schema: dict, property_name: str, mapping: dict) -> None:
+    assert [item["$ref"] for item in schema["oneOf"]] == [_ref(name) for name in dict.fromkeys(mapping.values())]
+    assert schema["discriminator"]["propertyName"] == property_name
+    assert schema["discriminator"]["mapping"] == {key: _ref(name) for key, name in mapping.items()}
+
+
+async def test_link_iface_response_is_discriminated(openapi: dict) -> None:
+    path = "/v3/projects/{project_id}/links/{link_id}/iface"
+    schema = openapi["paths"][path]["get"]["responses"]["200"]["content"]["application/json"]["schema"]
+    _assert_discriminated(schema, "kind", {"udp": "UDPPortInfo", "ethernet": "EthernetPortInfo"})
+
+
+async def test_appliance_version_request_is_discriminated(openapi: dict) -> None:
+    schema = openapi["paths"]["/v3/appliances/{appliance_id}/version"]["post"]["requestBody"]["content"][
+        "application/json"
+    ]["schema"]
+    mapping = {str(version): "ApplianceVersionCreateV1_6" for version in range(1, 7)}
+    mapping["8"] = "ApplianceVersionCreateV8"
+    _assert_discriminated(schema, "registry_version", mapping)
+
+
+async def test_appliance_settings_are_discriminated(openapi: dict) -> None:
+    schema = openapi["components"]["schemas"]["ApplianceV8"]["properties"]["settings"]["items"]
+    _assert_discriminated(
+        schema,
+        "template_type",
+        {
+            "qemu": "QemuTemplateSetting",
+            "dynamips": "DynamipsTemplateSetting",
+            "iou": "IouTemplateSetting",
+            "docker": "DockerTemplateSetting",
+        },
+    )