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java-topology/defects/storm/patch/storm-diamond-recursion-CLEAN.md
russell@unturf.com 1dee074618 kafka-0009: GraphGraceSearchUtil diamond recursion O(2^D) → O(N); count 621→622 
findAndVerifyWindowGrace() recurses over parent GraphNodes without a visited
accumulator. Kafka Streams GraphNode is a genuine DAG (addChild wires
parent→child with multiple parents allowed), so a diamond topology causes
2^D recursive calls. Fix: thread an IdentityHashMap<GraphNode,Long> memo
through recursion; memoize on first visit, return cached result on revisit.
8/8 unit tests PASS; D=10 defect count=3071 vs patched O(N).

Diamond-recursion CLEAN markers added for: flink, neo4j, janusgraph,
tinkerpop, dgraph, zookeeper, storm, ant, gradle, graal, eclipse-jdt,
exposed, intellij, kotlin, scala3, hibernate-0007 (prior session work
now committed).
2026-03-29 16:59:50 -04:00

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storm — diamond recursion CWE-407 scan: CLEAN

Scan date: 2026-03-29

Method scanned

Storm topology construction and validation: TopologyBuilder, StormTopology, worker task routing code.

Finding

Storm topology validation does not perform recursive graph traversal. Topology structure is built once via TopologyBuilder.createTopology() which iterates components linearly. No recursive cycle-detection or parent-ancestor walk was found that lacks a visited set.

The existing storm-0001 (Fields duplicate check linear scan) and storm-0002 (WorkerState localTaskIds list membership) were already filed. No new diamond recursion patterns were found.

Verdict: CLEAN