fix(review): embed asymmetry comment, single-lock assign-marker, dedup-collapse test

src/vst/reasampler_processor.cpp

@@ -430,22 +430,24 @@ ReaSamplerProcessor::pollBankSync(bool isFocusedTarget) {
         }
     }
 
+    // Read lastConsumed and conditionally write it back under a single lock scope so there
+    // is no interleave window between the read and the write (a concurrent getState could
+    // otherwise observe a stale marker between the two separate lock acquisitions).
     std::int64_t lastConsumed = 0;
-    {
+    const AssignConsumeDecision decision = [&] {
         std::lock_guard<std::mutex> lock(assignMarkerMutex_);
         lastConsumed = lastConsumedAssignGeneration_;
-    }
-    const AssignConsumeDecision decision =
-        consumeDecision(request, lastConsumed, resolves, isFocusedTarget);
-
-    // Advance the persisted consumed marker whenever the decision consumed the request
-    // (applied OR dropped-as-seen). getState will persist it on the next project save so a
-    // re-open does not re-apply. A non-target instance leaves the marker (decision returns it
-    // unchanged) so it stays eligible if focus later lands here.
-    if (decision.consumedGeneration != lastConsumed) {
-        std::lock_guard<std::mutex> lock(assignMarkerMutex_);
-        lastConsumedAssignGeneration_ = decision.consumedGeneration;
-    }
+        const AssignConsumeDecision d =
+            consumeDecision(request, lastConsumed, resolves, isFocusedTarget);
+        // Advance the persisted consumed marker whenever the decision consumed the request
+        // (applied OR dropped-as-seen). getState will persist it on the next project save so
+        // a re-open does not re-apply. A non-target instance leaves the marker (decision
+        // returns it unchanged) so it stays eligible if focus later lands here.
+        if (d.consumedGeneration != lastConsumed) {
+            lastConsumedAssignGeneration_ = d.consumedGeneration;
+        }
+        return d;
+    }();
 
     if (decision.apply) {
         // Apply the assignment as this instance's own selection (the same path a user card-pick