From 40254811bd94236df8c875bc40b51c0bcdb5187c Mon Sep 17 00:00:00 2001
From: beam <beam@agents.invalid>
Date: Sat, 24 Oct 2026 15:39:31 +0000
Subject: [PATCH] beam: topo_sort module + tests

---
 wizard-work/beam/test_toposort.py | 46 +++++++++++++++++++++++++++++++
 wizard-work/beam/toposort.py      |  4 +++
 2 files changed, 50 insertions(+)
 create mode 100644 wizard-work/beam/test_toposort.py

diff --git a/wizard-work/beam/test_toposort.py b/wizard-work/beam/test_toposort.py
new file mode 100644
index 0000000..2509ed4
--- /dev/null
+++ b/wizard-work/beam/test_toposort.py
@@ -0,0 +1,46 @@
+import sys
+sys.path.insert(0, '/root/.hermes/wizard-outputs/beam')
+from toposort import topo_sort
+
+def check(graph, expected_order=None):
+    r = topo_sort(graph)
+    if expected_order is not None:
+        assert r.cycle is None, (graph, r)
+        assert r.sorted == expected_order, (graph, r.sorted, expected_order)
+    return r
+
+# DAG simple
+check({'a': ['b'], 'b': []}, ['b','a'])
+# disconnected
+check({'a': [], 'b': []}, ['a','b'])
+# empty
+check({}, [])
+# diamond
+check({'a':['b','c'],'b':['d'],'c':['d'],'d':[]}, ['d','b','c','a'] if False else None) or True
+r = topo_sort({'a':['b','c'],'b':['d'],'c':['d'],'d':[]})
+assert r.cycle is None
+# verify validity
+pos = {n:i for i,n in enumerate(r.sorted)}
+for n,deps in {'a':['b','c'],'b':['d'],'c':['d'],'d':[]}.items():
+    for d in deps:
+        assert pos[d] < pos[n]
+# cycle
+r = topo_sort({'a':['b'],'b':['a']})
+assert r.sorted is None
+assert r.cycle is not None
+# cycle is valid: each consecutive edge exists and last->first
+g={'a':['b'],'b':['a']}
+cyc=r.cycle
+for i in range(len(cyc)):
+    u=cyc[i]; v=cyc[(i+1)%len(cyc)]
+    assert v in g.get(u,[]), (u,v,cyc)
+# self loop
+r = topo_sort({'a':['a']})
+assert r.sorted is None and r.cycle == ['a']
+# node only as successor
+r = topo_sort({'a':['b']})
+assert r.sorted == ['b','a']
+def test_all():
+    pass
+
+print("ALL PASS")
diff --git a/wizard-work/beam/toposort.py b/wizard-work/beam/toposort.py
index de77f22..4da0d8e 100644
--- a/wizard-work/beam/toposort.py
+++ b/wizard-work/beam/toposort.py
@@ -26,12 +26,16 @@ def topo_sort(graph: Mapping[Any, Iterable[Any]]) -> TopoResult:
     # Normalize: ensure every referenced node exists as a key.
     nodes: set[Any] = set(graph.keys())
     for deps in graph.values():
+        if deps is None:
+            continue
         for d in deps:
             nodes.add(d)
 
     # adjacency: node -> set of dependencies
     deps_of: dict[Any, set[Any]] = {n: set() for n in nodes}
     for n, ds in graph.items():
+        if ds is None:
+            ds = []
         for d in ds:
             if d == n:
                 # self-loop is a cycle of length 1