feat(other): answer model-versions-status read-only for unsupported types

Civitai types with no scanner at all (Wildcards, Workflows, Hypernetwork,
Poses, AestheticGradient) used to get a 400 'Model type "x" is not
supported', which hid the Civitai version list from clients.

The handler now answers 200 with supported:false, a machine-readable
reason (model_type_unsupported, or other_models_disabled when the opt-in
master switch is off) and the versions marked read-only. The interactive
payload gains an explicit supported:true. Legacy clients only read
success/versions, so they are unaffected.

py/routes/handlers/misc_handlers.py

@@ -2764,12 +2764,40 @@ class ModelLibraryHandler:
 
             normalized_type, scanner = await self._get_scanner_for_type(model_type)
             if not normalized_type:
+                # The lookup cannot be served as a fully interactive list. Two
+                # cases share this branch: a CivitAI type with no scanner at all
+                # (Wildcards, Workflows, Hypernetwork, Poses, AestheticGradient)
+                # and an Other-model type while the opt-in master switch is off.
+                # Answer 200 with the CivitAI list marked read-only plus a
+                # machine-readable reason, so clients can still show the
+                # versions and explain why the actions are missing. Legacy
+                # clients keep working: they only read `success`/`versions`.
+                reason = (
+                    "other_models_disabled"
+                    if self._normalize_model_type(model_type) == "other"
+                    else "model_type_unsupported"
+                )
                 return web.json_response(
                     {
-                        "success": False,
-                        "error": f'Model type "{model_type}" is not supported',
-                    },
-                    status=400,
+                        "success": True,
+                        "modelId": model_id,
+                        "modelName": model_name,
+                        "modelType": model_type,
+                        "supported": False,
+                        "reason": reason,
+                        "versions": [
+                            {
+                                "id": version.get("id"),
+                                "name": version.get("name", ""),
+                                "thumbnailUrl": version.get("images")[0]["url"]
+                                if version.get("images")
+                                else None,
+                                "inLibrary": False,
+                                "hasBeenDownloaded": False,
+                            }
+                            for version in versions
+                        ],
+                    }
                 )
 
             if not scanner:
@@ -2811,6 +2839,7 @@ class ModelLibraryHandler:
                     "modelId": model_id,
                     "modelName": model_name,
                     "modelType": model_type,
+                    "supported": True,
                     "versions": enriched_versions,
                 }
             )

tests/routes/test_misc_routes.py

@@ -2425,3 +2425,135 @@ async def test_get_init_status_reports_pending_scanners():
     assert "embedding" in payload["details"]
     assert "recipe" in payload["details"]
     assert "lora" not in payload["details"]
+
+
+class StaticMetadataProvider:
+    """Metadata provider returning one fixed CivitAI model payload."""
+
+    def __init__(self, payload):
+        self.payload = payload
+
+    async def get_model_versions(self, _model_id):
+        return self.payload
+
+    async def get_user_models(self, _username, cursor=None):
+        return {"items": [], "nextCursor": None}
+
+    async def get_creator_model_count(self, _username):
+        return None
+
+
+def _versions_status_handler(payload, *, other_scanner=None):
+    async def metadata_factory():
+        return StaticMetadataProvider(payload)
+
+    async def other_factory():
+        return other_scanner
+
+    return ModelLibraryHandler(
+        ServiceRegistryAdapter(
+            get_lora_scanner=fake_scanner_factory,
+            get_checkpoint_scanner=fake_scanner_factory,
+            get_embedding_scanner=fake_scanner_factory,
+            get_other_scanner=other_factory,
+            get_downloaded_version_history_service=fake_download_history_service_factory,
+        ),
+        metadata_provider_factory=metadata_factory,
+    )
+
+
+@pytest.mark.asyncio
+async def test_get_model_versions_status_unsupported_type_is_read_only():
+    """A type with no scanner answers 200 with a read-only list + reason."""
+    handler = _versions_status_handler(
+        {
+            "name": "Wildcards pack",
+            "type": "Wildcards",
+            "modelVersions": [
+                {"id": 11, "name": "v1", "images": [{"url": "https://img/1.png"}]},
+                {"id": 12, "name": "v2", "images": []},
+            ],
+        }
+    )
+
+    response = await handler.get_model_versions_status(
+        FakeRequest(query={"modelId": "45448"})  # pyright: ignore[reportArgumentType]
+    )
+    payload = _json_payload(response)
+
+    assert response.status == 200
+    assert payload["success"] is True
+    assert payload["supported"] is False
+    assert payload["reason"] == "model_type_unsupported"
+    assert payload["modelType"] == "wildcards"
+    assert payload["versions"] == [
+        {
+            "id": 11,
+            "name": "v1",
+            "thumbnailUrl": "https://img/1.png",
+            "inLibrary": False,
+            "hasBeenDownloaded": False,
+        },
+        {
+            "id": 12,
+            "name": "v2",
+            "thumbnailUrl": None,
+            "inLibrary": False,
+            "hasBeenDownloaded": False,
+        },
+    ]
+
+
+@pytest.mark.asyncio
+async def test_get_model_versions_status_other_disabled_is_read_only():
+    """The opt-in gate keeps its own reason instead of the permanent one."""
+    _set_other_models_enabled(False)
+    handler = _versions_status_handler(
+        {
+            "name": "SDXL VAE",
+            "type": "VAE",
+            "modelVersions": [{"id": 333245, "name": "SDXL-VAE", "images": []}],
+        }
+    )
+
+    response = await handler.get_model_versions_status(
+        FakeRequest(query={"modelId": "296576"})  # pyright: ignore[reportArgumentType]
+    )
+    payload = _json_payload(response)
+
+    assert response.status == 200
+    assert payload["success"] is True
+    assert payload["supported"] is False
+    assert payload["reason"] == "other_models_disabled"
+    assert payload["modelType"] == "vae"
+
+
+@pytest.mark.asyncio
+async def test_get_model_versions_status_supported_type_stays_interactive():
+    """A managed type keeps the existing enriched, fully interactive payload."""
+    handler = _versions_status_handler(
+        {
+            "name": "Some LoRA",
+            "type": "LORA",
+            "modelVersions": [{"id": 1, "name": "v1", "images": []}],
+        }
+    )
+
+    response = await handler.get_model_versions_status(
+        FakeRequest(query={"modelId": "5"})  # pyright: ignore[reportArgumentType]
+    )
+    payload = _json_payload(response)
+
+    assert response.status == 200
+    assert payload["success"] is True
+    assert payload["supported"] is True
+    assert "reason" not in payload
+    assert payload["versions"] == [
+        {
+            "id": 1,
+            "name": "v1",
+            "thumbnailUrl": None,
+            "inLibrary": False,
+            "hasBeenDownloaded": False,
+        }
+    ]