fix(toolbox): mesh-exclusion union tolerates malformed blob fields (ref #806)

The union_blobs function now guards against non-list field values (e.g. int,
bool, None) that could cause TypeError during iteration. Instead of assuming
a field is always a list, the function checks isinstance() before iterating.

Adds test_union_blobs_tolerates_malformed_fields() to verify that a valid
blob with malformed fields does not crash the entire federation sync.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

packages/secubox-toolbox/secubox_toolbox/mesh_exclusion.py

@@ -185,9 +185,10 @@ def pull_blobs() -> list:
 def union_blobs(blobs: list) -> dict:
     s, b, d = set(), set(), set()
     for p in blobs:
-        s.update(x for x in (p.get("splice") or []) if isinstance(x, str))
-        b.update(x for x in (p.get("bypass") or []) if isinstance(x, str))
-        d.update(x for x in (p.get("disabled") or []) if isinstance(x, str))
+        for key, acc in (("splice", s), ("bypass", b), ("disabled", d)):
+            v = p.get(key)
+            if isinstance(v, list):
+                acc.update(x for x in v if isinstance(x, str))
     return {"splice": sorted(s)[:FED_MAX], "bypass": sorted(b)[:FED_MAX],
             "disabled": sorted(d)[:FED_MAX]}
 

packages/secubox-toolbox/tests/test_mesh_exclusion_sync.py

@@ -24,3 +24,15 @@ def test_sync_writes_fed_files_only_on_change(tmp_path, monkeypatch):
     assert r1["changed"] is True
     r2 = mx.sync()                # same content → no rewrite
     assert r2["changed"] is False
+
+
+def test_union_blobs_tolerates_malformed_fields():
+    # a verified-but-malformed blob (non-list field) must be skipped, not crash
+    blobs = [
+        {"node": "bad", "splice": 123, "bypass": True, "disabled": None},
+        {"node": "ok", "splice": ["a.com"], "bypass": [], "disabled": ["d.com"]},
+    ]
+    u = mx.union_blobs(blobs)          # must not raise
+    assert u["splice"] == ["a.com"]
+    assert u["disabled"] == ["d.com"]
+    assert u["bypass"] == []