fast workers are fast :D

Author: ndyakov

hitless/pool_hook.go

@@ -151,8 +151,20 @@ func (ph *PoolHook) OnPut(ctx context.Context, conn *pool.Conn) (shouldPool bool
 					internal.Logger.Printf(ctx, "Failed to queue handoff: %v", err)
 					return false, true, nil // Don't pool, remove connection, no error to caller
 				}
+
+				// Check if handoff was already processed by a worker before we can mark it as queued
+				if !conn.ShouldHandoff() {
+					// Handoff was already processed - this is normal and the connection should be pooled
+					return true, false, nil
+				}
+
 				if err := conn.MarkQueuedForHandoff(); err != nil {
-					// If marking fails, remove the connection instead
+					// If marking fails, check if handoff was processed in the meantime
+					if !conn.ShouldHandoff() {
+						// Handoff was processed - this is normal, pool the connection
+						return true, false, nil
+					}
+					// Other error - remove the connection
 					return false, true, nil
 				}
 				return true, false, nil
@@ -281,10 +293,12 @@ func (ph *PoolHook) queueHandoff(conn *pool.Conn) error {
 			return nil
 		default:
 			// Queue is full - log and attempt scaling
+			queueLen := len(ph.handoffQueue)
+			queueCap := cap(ph.handoffQueue)
 			if ph.config != nil && ph.config.LogLevel >= 1 { // Warning level
 				internal.Logger.Printf(context.Background(),
 					"hitless: handoff queue is full (%d/%d), attempting timeout queuing and scaling workers",
-					len(ph.handoffQueue), cap(ph.handoffQueue))
+					queueLen, queueCap)
 			}
 		}
 	}

hitless/pool_hook_test.go

@@ -735,22 +735,22 @@ func TestConnectionHook(t *testing.T) {
 			if err != nil {
 				t.Errorf("Failed to queue handoff %d: %v", i, err)
 			}
+
 			if !shouldPool || shouldRemove {
-				t.Errorf("Connection %d should be pooled after handoff", i)
+				t.Errorf("Connection %d should be pooled after handoff (shouldPool=%v, shouldRemove=%v)",
+					i, shouldPool, shouldRemove)
 			}
 		}
 
 		// Verify queue capacity remains static (the main purpose of this test)
 		finalCapacity := cap(processor.handoffQueue)
+
 		if finalCapacity != 50 {
 			t.Errorf("Queue capacity should remain static at 50, got %d", finalCapacity)
 		}
 
 		// Note: We don't check queue size here because workers process items quickly
 		// The important thing is that the capacity remains static regardless of pool size
-		currentQueueSize := len(processor.handoffQueue)
-		t.Logf("Static queue test completed - Capacity: %d, Current size: %d",
-			finalCapacity, currentQueueSize)
 	})
 
 	t.Run("ConnectionRemovalOnHandoffFailure", func(t *testing.T) {