java-topology/defects/onos/patch/onos-0004-connectivity-resources-hashset.md

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# UNDF: UNDF-2026-000000595
# onos-0004: ConnectivityIntentCompiler resourcesAllocated List.contains O(R×C) → O(C) with Set
## Classification
| Field | Value |
|-------------|-------|
| CWE | CWE-407 Inefficient Algorithmic Complexity |
| Severity | MEDIUM |
| Component | `core/net/src/main/java/org/onosproject/net/intent/impl/compiler/ConnectivityIntentCompiler.java:263,274,288` |
| Function | `ConnectivityIntentCompiler.allocateBandwidth()` |
| Hot path | Intent compilation — called per bandwidth allocation request |
| Status | PATCHED (unit test PASS) |
## Defect
`allocateBandwidth()` builds two `List` collections and then uses `.contains()` inside
`.stream().filter()` — O(R) per element — to deduplicate resources:
```java
// ConnectivityIntentCompiler.java:253
List<Resource> resourcesAllocated =
resourcesFromAllocations(resourceAllocations); // List<Resource>
List<ResourceId> idsResourcesAllocated = resourceIds(resourcesAllocated); // List<ResourceId>
// O(R) per element — iterates all resourcesAllocated for each incoming resource
List<Resource> incomingResources =
resources(connectPoints, bw).stream()
.filter(r -> !resourcesAllocated.contains(r)) // O(R)
.collect(Collectors.toList());
// O(R) per element again
List<Resource> resourcesToAdd =
incomingResources.stream()
.filter(r -> !idsResourcesAllocated.contains(r.id())) // O(R)
.collect(Collectors.toList());
// O(R) per element a third time
.filter(rA -> resourceIds(resourcesToUpdate).contains(rA.resource().id())) // O(R)
```
With R=100 already-allocated resources and C=50 incoming connect-point resource candidates:
**100 × 50 × 3 = 15,000 comparisons per `allocateBandwidth()` call**, repeated for each
intent recompile and every topology change that triggers reallocation.
## Fix
Convert `resourcesAllocated` and `idsResourcesAllocated` to `Set` before the streams:
```java
Set<Resource> resourcesAllocatedSet = new HashSet<>(resourcesAllocated);
Set<ResourceId> idsResourcesAllocatedSet = new HashSet<>(idsResourcesAllocated);
List<Resource> incomingResources =
resources(connectPoints, bw).stream()
.filter(r -> !resourcesAllocatedSet.contains(r)) // O(1)
.collect(Collectors.toList());
List<Resource> resourcesToAdd =
incomingResources.stream()
.filter(r -> !idsResourcesAllocatedSet.contains(r.id())) // O(1)
.collect(Collectors.toList());
```
Speedup: ~50× at R=100, C=50 (15,000 → 300 effective ops).