Harden topology tree against bad view filters and allow deleting UME World.

Coerce non-dict filter JSON so /tree no longer 500s, surface API failure details, and let users remove the UME World container for local resets.

Co-authored-by: Cursor <cursoragent@cursor.com>

netx_api/topology_common.py

@@ -19,6 +19,14 @@ PHYSICAL_VIEW_NAME = "Physical topology"
 # Legacy system region name (no longer auto-created; stripped on bootstrap when empty).
 _LEGACY_UNASSIGNED_NAME = "Unassigned"
 
+
+def view_filter_dict(raw: Any) -> dict[str, Any]:
+    """Coerce TopoView.filter JSON to a dict (bad rows must not 500 the tree)."""
+    if isinstance(raw, dict):
+        return dict(raw)
+    return {}
+
+
 PAGE_DEFAULT = 100
 PAGE_MAX = 2000
 VIEW_GRAPH_NODE_HARD_CAP = 2000

netx_api/topology_router.py

@@ -248,12 +248,32 @@ def api_fabric_discover_job(
 
 @router.get("/tree")
 def api_topology_tree(db: Session = Depends(get_db)) -> dict[str, Any]:
-    return get_topology_tree(db).model_dump()
+    try:
+        return get_topology_tree(db).model_dump(mode="json")
+    except Exception as exc:
+        import logging
+
+        logging.getLogger("netx.topology").exception("GET /v1/topology/tree failed")
+        raise HTTPException(
+            status_code=500,
+            detail=f"topology_tree_failed:{type(exc).__name__}:{exc}",
+        ) from exc
 
 
 @router.post("/folders")
 def api_create_folder(body: TopologyFolderCreate, db: Session = Depends(get_db)) -> dict[str, Any]:
-    return create_folder(db, body).model_dump()
+    try:
+        return create_folder(db, body).model_dump(mode="json")
+    except HTTPException:
+        raise
+    except Exception as exc:
+        import logging
+
+        logging.getLogger("netx.topology").exception("POST /v1/topology/folders failed")
+        raise HTTPException(
+            status_code=500,
+            detail=f"topology_folder_create_failed:{type(exc).__name__}:{exc}",
+        ) from exc
 
 
 @router.patch("/folders/{folder_id}")

netx_api/topology_views_tree.py

@@ -28,6 +28,7 @@ from .topology_common import (
     _LEGACY_UNASSIGNED_NAME,
     _normalize_edge_status,
     _utcnow,
+    view_filter_dict,
 )
 
 # Manual top-level「根」auto-spawns this unique L2 canvas (mirrors UME World / World).
@@ -101,7 +102,7 @@ def _view_out(v: TopoView, *, node_count: int = 0) -> TopologyViewOut:
         kind=normalize_view_kind(getattr(v, "kind", None)),
         role=normalize_view_role(v.role),
         sort_order=int(v.sort_order or 0),
-        filter=dict(v.filter or {}),
+        filter=view_filter_dict(v.filter),
         viewport=dict(v.viewport or {}),
         node_count=node_count,
         created_at=v.created_at,
@@ -357,7 +358,7 @@ def bootstrap_topology_tree(db: Session) -> dict[str, str]:
         if not str(v.role or "").strip():
             v.role = "core"
             changed = True
-        filt = dict(v.filter or {})
+        filt = view_filter_dict(v.filter)
         if "membership" not in filt:
             v.filter = merge_filter_with_membership(
                 filt, role=normalize_view_role(v.role), kind=kind
@@ -548,13 +549,19 @@ def update_folder(db: Session, folder_id: str, body: TopologyFolderUpdate) -> To
 def delete_folder(db: Session, folder_id: str, *, force: bool = False) -> dict[str, Any]:
     """Delete a region and cascade-delete nested regions + maps.
 
-    ``force`` is accepted for API compatibility; cascade always runs.
     System L2「根图」may be removed only as part of cascading from its parent「根」.
+    UME World container may be deleted explicitly (cascades all synced SBN folders);
+    a later UME apply / world ensure can recreate it.
     """
     row = _get_folder_or_404(db, folder_id)
     if str(row.kind or "") == "root":
         raise HTTPException(status_code=400, detail="cannot_delete_system_folder")
-    if bool(row.is_system):
+
+    from .ume_topology_world import is_ume_world_container
+
+    # UME World container is system-marked but user-deletable (cascades SBN tree).
+    # Manual「根图」and other system folders stay protected except via parent cascade.
+    if bool(row.is_system) and not is_ume_world_container(row):
         raise HTTPException(status_code=400, detail="cannot_delete_system_folder")
     _ = force
     from .topology_region_canvas import remove_region_canvas_placements
@@ -583,7 +590,14 @@ def delete_folder(db: Session, folder_id: str, *, force: bool = False) -> dict[s
     _purge_folder(row)
     from .ume_topology_world import reconcile_world_flat_view
 
-    reconcile_world_flat_view(db)
+    try:
+        reconcile_world_flat_view(db)
+    except Exception:
+        import logging
+
+        logging.getLogger("netx.topology").exception(
+            "reconcile_world_flat_view failed after delete_folder id=%s", folder_id
+        )
     db.commit()
     return {"ok": True, "folder_id": folder_id, "deleted": True}
 
@@ -618,9 +632,9 @@ def get_topology_tree(db: Session) -> TopologyTreeOut:
         if str(f.kind or "") == "region"
     ) or any(
         bool(
-            dict(v.filter or {}).get("ume_level")
-            or dict(v.filter or {}).get("world")
-            or dict(v.filter or {}).get("world_flat")
+            view_filter_dict(v.filter).get("ume_level")
+            or view_filter_dict(v.filter).get("world")
+            or view_filter_dict(v.filter).get("world_flat")
         )
         for v in views
     )
@@ -669,7 +683,7 @@ def get_topology_tree(db: Session) -> TopologyTreeOut:
         ne_nc = max(0, raw - int(region_icon_map.get(v.id, 0) or 0))
         if ne_nc:
             return ne_nc
-        filt = dict(v.filter or {})
+        filt = view_filter_dict(v.filter)
         if filt.get("world_flat") or (
             bool(filt.get("world")) and not filt.get("ume_level")
         ):

netx_api/ume_topology_world.py

@@ -29,7 +29,9 @@ WORLD_FLAT_FILTER = {"world_flat": True}
 def _filt(view: TopoView | None) -> dict[str, Any]:
     if view is None:
         return {}
-    return dict(view.filter or {})
+    from .topology_common import view_filter_dict
+
+    return view_filter_dict(getattr(view, "filter", None))
 
 
 def is_ume_level_view(view: TopoView | None) -> bool:

web/src/i18n/en.ts

@@ -1441,6 +1441,8 @@ const en = {
     regionDeleted: "Deleted",
     deleteRegion: "Delete",
     deleteRegionConfirm: "Delete \"{{name}}\"? Its maps will also be deleted.",
+    deleteUmeWorldConfirm:
+      "Delete \"{{name}}\"? This cascades all UME regions and maps under it. A later UME topology apply may recreate it.",
     renameRegion: "Rename",
     renameRegionPrompt: "Name",
     regionRenamed: "Renamed",

web/src/i18n/zh.ts

@@ -1431,6 +1431,8 @@ const zh = {
     regionDeleted: "已删除",
     deleteRegion: "删除",
     deleteRegionConfirm: "删除「{{name}}」？其下画布将一并删除。",
+    deleteUmeWorldConfirm:
+      "删除「{{name}}」？将级联删除其下全部 UME 区域与画布。之后若再跑 UME 拓扑同步/应用，可能重新生成。",
     renameRegion: "重命名",
     renameRegionPrompt: "名称",
     regionRenamed: "已重命名",

web/src/pages/TopologyPage.tsx

@@ -2318,30 +2318,38 @@ export function TopologyPage() {
                 </span>
               </span>
             </button>
-            {!umeNav ? (
+            {!umeNav || containerFolder ? (
               <div className="topo-map-list__actions">
-                <button
-                  type="button"
-                  className="topo-map-list__icon"
-                  title={t("topology.renameRegion")}
-                  aria-label={t("topology.renameRegion")}
-                  disabled={!!folder.is_system || renameRegionMut.isPending}
-                  onClick={() => promptRenameRegion(folder.id, folder.name)}
-                >
-                  <PencilIcon />
-                </button>
+                {!containerFolder ? (
+                  <button
+                    type="button"
+                    className="topo-map-list__icon"
+                    title={t("topology.renameRegion")}
+                    aria-label={t("topology.renameRegion")}
+                    disabled={!!folder.is_system || renameRegionMut.isPending}
+                    onClick={() => promptRenameRegion(folder.id, folder.name)}
+                  >
+                    <PencilIcon />
+                  </button>
+                ) : null}
                 <button
                   type="button"
                   className="topo-map-list__icon"
                   title={t("topology.deleteRegion")}
                   aria-label={t("topology.deleteRegion")}
-                  disabled={!!folder.is_system}
+                  disabled={
+                    deleteFolderMut.isPending ||
+                    (!!folder.is_system && !containerFolder)
+                  }
                   onClick={() => {
-                    const msg = t("topology.deleteRegionConfirm").replace(
-                      "{{name}}",
-                      folder.name,
-                    );
-                    if (window.confirm(msg)) deleteFolderMut.mutate(folder.id);
+                    const msg = (
+                      containerFolder
+                        ? t("topology.deleteUmeWorldConfirm")
+                        : t("topology.deleteRegionConfirm")
+                    ).replace("{{name}}", folder.name);
+                    if (window.confirm(msg)) {
+                      deleteFolderMut.mutate(folder.id);
+                    }
                   }}
                 >
                   <CloseIcon />
@@ -4116,7 +4124,10 @@ export function TopologyPage() {
                     </>
                   ) : treeFailed ? (
                     <>
-                      {t("topology.treeLoadFailed")}{" "}
+                      {t("topology.treeLoadFailed")}
+                      {treeQuery.error ? (
+                        <span className="muted"> ({String(treeQuery.error)})</span>
+                      ) : null}{" "}
                       <button
                         type="button"
                         className="btn btn--sm btn--ghost"