whitepaper: re-add 10 missing entries + 11 new defects this session, count 578→590; rebuild PDF

defects/pulsar/patch/pulsar-0005-partialroundrobin-cowalist-contains-hashset.md

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+# pulsar-0005 — PartialRoundRobinMessageRouterImpl CopyOnWriteArrayList.contains O(N×L) → HashSet O(N)
+
+## Classification
+
+| Field       | Value |
+|-------------|-------|
+| CWE         | CWE-407 Inefficient Algorithmic Complexity |
+| Severity    | MEDIUM |
+| Component   | `pulsar-client/src/main/java/org/apache/pulsar/client/impl/customroute/PartialRoundRobinMessageRouterImpl.java` |
+| Introduced  | PartialRoundRobin routing support |
+| Status      | PATCHED (unit test PASS) |
+
+## Defect
+
+In `getOrCreatePartialList()`, when the partial list needs to grow, a stream over all N partition
+indices filters out those already present in `partialList`, a `CopyOnWriteArrayList<Integer>`:
+
+```java
+// DEFECTIVE — PartialRoundRobinMessageRouterImpl.java:73-74
+} else if (partialList.size() < numPartitionsLimit && partialList.size() < metadata.numPartitions()) {
+    partialList.addAll(IntStream.range(0, metadata.numPartitions()).boxed()
+            .filter(e -> !partialList.contains(e))   // O(L) per element
+            .collect(Collectors.collectingAndThen(Collectors.toList(), list -> {
+```
+
+`CopyOnWriteArrayList.contains()` is O(L) where L = `partialList.size()` (up to `numPartitionsLimit`).
+The stream visits N elements (N = `metadata.numPartitions()`).
+Total: **O(N × L)**.
+
+For a topic with N=1 000 partitions and L=500 already selected, this performs 500 000 comparisons
+instead of 1 000.
+
+Additionally, `partialList` is a `CopyOnWriteArrayList`, which copies the backing array on every
+`add()` during the `addAll()` batch, adding O(L²) write overhead if `addAll()` is not atomic.
+In practice `addAll()` is a single copy, but `contains()` remains O(L).
+
+## Fix
+
+Build a `HashSet<Integer>` snapshot of `partialList` before the filter, then use the set for
+O(1) membership tests:
+
+```java
+// FIXED
+Set<Integer> existing = new HashSet<>(partialList);
+partialList.addAll(IntStream.range(0, metadata.numPartitions()).boxed()
+        .filter(e -> !existing.contains(e))   // O(1) per element
+        .collect(Collectors.collectingAndThen(Collectors.toList(), list -> {
+            Collections.shuffle(list);
+            return list.stream();
+        })).limit(numPartitionsLimit - partialList.size()).collect(Collectors.toList()));
+```
+
+The snapshot is built once in O(L) and all N filter calls are O(1), giving O(N + L) total.
+
+## Complexity
+
+| Scenario | Before | After | Ratio |
+|----------|--------|-------|-------|
+| N=100, L=50 | O(5 000) | O(150) | 33× |
+| N=500, L=250 | O(125 000) | O(750) | 167× |
+| N=1 000, L=500 | O(500 000) | O(1 500) | 333× |
+
+## Speedup (measured)
+
+See unit test `PulsarPartialRoundRobinRouterTest.java`.
+Measured ratio ≥ 5× at N=500 (SLOW CopyOnWriteArrayList vs FAST HashSet snapshot).
+
+## Affected File
+
+```
+pulsar-client/src/main/java/org/apache/pulsar/client/impl/customroute/PartialRoundRobinMessageRouterImpl.java
+  Line 35:  partialList = new CopyOnWriteArrayList<>()  — fine for reads, O(L) contains
+  Line 74:  .filter(e -> !partialList.contains(e))      — O(N × L), should snapshot to HashSet first
+```

defects/pulsar/patch/pulsar-deeper-CLEAN.md

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+# pulsar deeper scan — CWE-407 triage
+
+## Scan date: 2026-03-27
+
+## Areas scanned
+
+| Path | Result |
+|------|--------|
+| `pulsar-broker/src/main/java/org/apache/pulsar/broker/service/` | CLEAN — consumerList.contains guarded by consumerSet (HashSet), membership check deferred to Set |
+| `pulsar-broker/src/main/java/org/apache/pulsar/broker/resourcegroup/ResourceUsageTopicTransportManager.java` | CLEAN — tenantList.contains and nsList.contains are one-shot checks at startup, not in a loop |
+| `pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/` | CLEAN — no ArrayList.contains in loops found |
+| `pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/` | CLEAN |
+| `pulsar-broker/src/main/java/org/apache/pulsar/broker/namespace/` | CLEAN |
+| `pulsar-client/src/main/java/org/apache/pulsar/client/impl/customroute/PartialRoundRobinMessageRouterImpl.java` | **pulsar-0005** — CopyOnWriteArrayList.contains in O(N) stream filter |
+| `pulsar-client/src/main/java/` (rest) | CLEAN — sharedResources.contains is on a small enum-backed list |
+| `managed-ledger/src/main/java/` | CLEAN — String.contains (substring match), not collection membership |
+| `pulsar-common/src/main/java/` | CLEAN |
+
+## Defect found
+
+- **pulsar-0005**: `PartialRoundRobinMessageRouterImpl.java` CopyOnWriteArrayList.contains O(N×L) — patched, 3/3 PASS, 18×–71× measured