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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Apache Ant — Diamond Recursion CWE-407 Scan: CLEAN

Pattern: Recursive cycle/reachability without visited set (O(2^D) on diamond DAGs) Scan date: 2026-03-29 Scope: src/main/org/apache/tools/ant/

Method

Searched for isCyclic, hasCycle, createsCycle, addsCycle, willCycle, isReachable, canReach, hasPath, detectCycle across all Java sources. Checked each hit for recursive traversal lacking a visited-accumulator parameter.

Key candidate: `Project.tsort()`

src/main/org/apache/tools/ant/Project.java lines 1898–1939: the target dependency topological sort passes a Hashtable<String, String> state through every recursive call. State values are VISITING/VISITED. This is a proper DFS with O(1) visit check per node — not the diamond recursion anti-pattern.

Other candidates

File	Method	Verdict
`Project.java`	`tsort()`	Passes `state` Hashtable — CLEAN
`taskdefs/optional/depend/Depend.java`	`isRmiStub()` / `isStub()`	Not recursive on a DAG — CLEAN
`taskdefs/condition/IsReachable.java`	Network connectivity check	Not a graph traversal — CLEAN

Verdict

CLEAN. No diamond recursion CWE-407 found. Ant's dependency resolution uses a state-tracking Hashtable (equivalent to a visited set) through all recursive calls.

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