Merge pull request #940 from iotaledger/fix/lazyinit

Fix: Prevent spawning of unnecessary chains

pkg/protocol/commitment.go

@@ -93,7 +93,7 @@ type Commitment struct {
 
 // NewCommitment creates a new Commitment from the given model.Commitment.
 func newCommitment(commitments *Commitments, model *model.Commitment) *Commitment {
-	c := &Commitment{
+	return &Commitment{
 		Commitment:                      model,
 		Parent:                          reactive.NewVariable[*Commitment](),
 		Children:                        reactive.NewSet[*Commitment](),
@@ -116,16 +116,8 @@ func newCommitment(commitments *Commitments, model *model.Commitment) *Commitmen
 		ReplayDroppedBlocks:             reactive.NewVariable[bool](),
 		IsEvicted:                       reactive.NewEvent(),
 		commitments:                     commitments,
+		Logger:                          commitments.NewChildLogger(fmt.Sprintf("Slot%d.", model.Slot()), true),
 	}
-
-	shutdown := lo.BatchReverse(
-		c.initLogger(),
-		c.initDerivedProperties(),
-	)
-
-	c.IsEvicted.OnTrigger(shutdown)
-
-	return c
 }
 
 // TargetEngine returns the engine that is responsible for booking the blocks of this Commitment.
@@ -203,10 +195,18 @@ func (c *Commitment) Less(other *Commitment) bool {
 	}
 }
 
+// initBehavior initializes the behavior of this Commitment by setting up the relations between its properties.
+func (c *Commitment) initBehavior() {
+	shutdown := lo.BatchReverse(
+		c.initLogger(),
+		c.initDerivedProperties(),
+	)
+
+	c.IsEvicted.OnTrigger(shutdown)
+}
+
 // initLogger initializes the Logger of this Commitment.
 func (c *Commitment) initLogger() (shutdown func()) {
-	c.Logger = c.commitments.NewChildLogger(fmt.Sprintf("Slot%d.", c.Slot()), true)
-
 	return lo.BatchReverse(
 		c.Parent.LogUpdates(c, log.LevelTrace, "Parent", (*Commitment).LogName),
 		c.MainChild.LogUpdates(c, log.LevelTrace, "MainChild", (*Commitment).LogName),

pkg/protocol/commitments.go

@@ -187,26 +187,31 @@ func (c *Commitments) publishEngineCommitments(chain *Chain, engine *engine.Engi
 			}
 
 			// publish the commitment
-			publishedCommitment, _, err := c.publishCommitment(commitment)
+			publishedCommitment, published, err := c.publishCommitment(commitment, true)
 			if err != nil {
 				c.LogError("failed to publish commitment from engine", "engine", engine.LogName(), "commitment", commitment, "err", err)
 
 				return
 			}
 
+			// force the chain before initializing the behavior to prevent the creation of unnecessary chains
+			publishedCommitment.forceChain(chain)
+			if published {
+				publishedCommitment.initBehavior()
+			}
+
 			// mark it as produced by ourselves and force it to be on the right chain (in case our chain produced a
 			// different commitment than the one we erroneously expected it to be - we always trust our engine most).
 			publishedCommitment.AttestedWeight.Set(publishedCommitment.Weight.Get())
 			publishedCommitment.IsVerified.Set(true)
-			publishedCommitment.forceChain(chain)
 		}
 	})
 }
 
 // publishCommitment publishes the given commitment and returns the singleton Commitment instance that is used to
 // represent it in our data structure (together with a boolean that indicates if we were the first goroutine to publish
 // the commitment).
-func (c *Commitments) publishCommitment(commitment *model.Commitment) (publishedCommitment *Commitment, published bool, err error) {
+func (c *Commitments) publishCommitment(commitment *model.Commitment, initManually ...bool) (publishedCommitment *Commitment, published bool, err error) {
 	// retrieve promise and abort if it was already rejected
 	cachedRequest := c.cachedRequest(commitment.ID())
 	if cachedRequest.WasRejected() {
@@ -215,9 +220,14 @@ func (c *Commitments) publishCommitment(commitment *model.Commitment) (published
 
 	// otherwise try to publish it and determine if we were the goroutine that published it
 	cachedRequest.ResolveDynamically(func() *Commitment {
+		publishedCommitment = newCommitment(c, commitment)
 		published = true
 
-		return newCommitment(c, commitment)
+		if !lo.First(initManually) {
+			publishedCommitment.initBehavior()
+		}
+
+		return publishedCommitment
 	})
 
 	return cachedRequest.Result(), published, nil