merkledb -- remove unneeded return values (#1959)

Author: Dan Laine

x/merkledb/db.go

@@ -1085,9 +1085,7 @@ func (db *merkleDB) initializeRootIfNeeded() (ids.ID, error) {
 	}
 	if err == nil {
 		// Root already exists, so calculate its id
-		if err := db.root.calculateID(db.metrics); err != nil {
-			return ids.Empty, err
-		}
+		db.root.calculateID(db.metrics)
 		return db.root.id, nil
 	}
 	if err != database.ErrNotFound {
@@ -1098,9 +1096,7 @@ func (db *merkleDB) initializeRootIfNeeded() (ids.ID, error) {
 	db.root = newNode(nil, RootPath)
 
 	// update its ID
-	if err := db.root.calculateID(db.metrics); err != nil {
-		return ids.Empty, err
-	}
+	db.root.calculateID(db.metrics)
 
 	if err := db.intermediateNodeDB.Put(RootPath, db.root); err != nil {
 		return ids.Empty, err

x/merkledb/node.go

@@ -98,21 +98,18 @@ func (n *node) onNodeChanged() {
 }
 
 // Returns and caches the ID of this node.
-func (n *node) calculateID(metrics merkleMetrics) error {
+func (n *node) calculateID(metrics merkleMetrics) {
 	if n.id != ids.Empty {
-		return nil
+		return
 	}
 
-	hv := &hashValues{
+	metrics.HashCalculated()
+	bytes := codec.encodeHashValues(&hashValues{
 		Children: n.children,
 		Value:    n.valueDigest,
 		Key:      n.key.Serialize(),
-	}
-
-	bytes := codec.encodeHashValues(hv)
-	metrics.HashCalculated()
+	})
 	n.id = hashing.ComputeHash256Array(bytes)
-	return nil
 }
 
 // Set [n]'s value to [val].

x/merkledb/node_test.go

@@ -21,7 +21,7 @@ func Test_Node_Marshal(t *testing.T) {
 	childNode.setValue(maybe.Some([]byte("value")))
 	require.NotNil(t, childNode)
 
-	require.NoError(t, childNode.calculateID(&mockMetrics{}))
+	childNode.calculateID(&mockMetrics{})
 	root.addChild(childNode)
 
 	data := root.bytes()
@@ -45,15 +45,15 @@ func Test_Node_Marshal_Errors(t *testing.T) {
 	childNode1.setValue(maybe.Some([]byte("value1")))
 	require.NotNil(t, childNode1)
 
-	require.NoError(t, childNode1.calculateID(&mockMetrics{}))
+	childNode1.calculateID(&mockMetrics{})
 	root.addChild(childNode1)
 
 	fullpath = newPath([]byte{237})
 	childNode2 := newNode(root, fullpath)
 	childNode2.setValue(maybe.Some([]byte("value2")))
 	require.NotNil(t, childNode2)
 
-	require.NoError(t, childNode2.calculateID(&mockMetrics{}))
+	childNode2.calculateID(&mockMetrics{})
 	root.addChild(childNode2)
 
 	data := root.bytes()

x/merkledb/trieview.go

@@ -242,9 +242,7 @@ func (t *trieView) calculateNodeIDs(ctx context.Context) error {
 		// [eg] limits the number of goroutines we start.
 		var eg errgroup.Group
 		eg.SetLimit(t.db.rootGenConcurrency)
-		if err = t.calculateNodeIDsHelper(ctx, t.root, &eg); err != nil {
-			return
-		}
+		t.calculateNodeIDsHelper(ctx, t.root, &eg)
 		if err = eg.Wait(); err != nil {
 			return
 		}
@@ -261,7 +259,7 @@ func (t *trieView) calculateNodeIDs(ctx context.Context) error {
 
 // Calculates the ID of all descendants of [n] which need to be recalculated,
 // and then calculates the ID of [n] itself.
-func (t *trieView) calculateNodeIDsHelper(ctx context.Context, n *node, eg *errgroup.Group) error {
+func (t *trieView) calculateNodeIDsHelper(ctx context.Context, n *node, eg *errgroup.Group) {
 	var (
 		// We use [wg] to wait until all descendants of [n] have been updated.
 		// Note we can't wait on [eg] because [eg] may have started goroutines
@@ -281,24 +279,22 @@ func (t *trieView) calculateNodeIDsHelper(ctx context.Context, n *node, eg *errg
 		}
 
 		wg.Add(1)
-		updateChild := func() error {
+		updateChild := func() {
 			defer wg.Done()
 
-			if err := t.calculateNodeIDsHelper(ctx, childNodeChange.after, eg); err != nil {
-				return err
-			}
+			t.calculateNodeIDsHelper(ctx, childNodeChange.after, eg)
 
 			// Note that this will never block
 			updatedChildren <- childNodeChange.after
-			return nil
 		}
 
 		// Try updating the child and its descendants in a goroutine.
-		if ok := eg.TryGo(updateChild); !ok {
+		if ok := eg.TryGo(func() error {
+			updateChild()
+			return nil
+		}); !ok {
 			// We're at the goroutine limit; do the work in this goroutine.
-			if err := updateChild(); err != nil {
-				return err
-			}
+			updateChild()
 		}
 	}
 
@@ -311,7 +307,7 @@ func (t *trieView) calculateNodeIDsHelper(ctx context.Context, n *node, eg *errg
 	}
 
 	// The IDs [n]'s descendants are up to date so we can calculate [n]'s ID.
-	return n.calculateID(t.db.metrics)
+	n.calculateID(t.db.metrics)
 }
 
 // GetProof returns a proof that [bytesPath] is in or not in trie [t].