Remove .Status() from .Accepted() (#3124)

snow/consensus/snowman/snowman_block.go

@@ -5,14 +5,12 @@ package snowman
 
 import (
 	"github.com/ava-labs/avalanchego/ids"
-	"github.com/ava-labs/avalanchego/snow/choices"
 	"github.com/ava-labs/avalanchego/snow/consensus/snowball"
 )
 
 // Tracks the state of a snowman block
 type snowmanBlock struct {
-	// parameters to initialize the snowball instance with
-	params snowball.Parameters
+	t *Topological
 
 	// block that this node contains. For the genesis, this value will be nil
 	blk Block
@@ -38,7 +36,7 @@ func (n *snowmanBlock) AddChild(child Block) {
 	// if the snowball instance is nil, this is the first child. So the instance
 	// should be initialized.
 	if n.sb == nil {
-		n.sb = snowball.NewTree(snowball.SnowballFactory, n.params, childID)
+		n.sb = snowball.NewTree(snowball.SnowballFactory, n.t.params, childID)
 		n.children = make(map[ids.ID]Block)
 	} else {
 		n.sb.Add(childID)
@@ -47,11 +45,8 @@ func (n *snowmanBlock) AddChild(child Block) {
 	n.children[childID] = child
 }
 
-func (n *snowmanBlock) Accepted() bool {
+func (n *snowmanBlock) Decided() bool {
 	// if the block is nil, then this is the genesis which is defined as
 	// accepted
-	if n.blk == nil {
-		return true
-	}
-	return n.blk.Status() == choices.Accepted
+	return n.blk == nil || n.blk.Height() <= n.t.lastAcceptedHeight
 }

snow/consensus/snowman/topological.go

@@ -126,7 +126,7 @@ func (ts *Topological) Initialize(
 	ts.lastAcceptedID = lastAcceptedID
 	ts.lastAcceptedHeight = lastAcceptedHeight
 	ts.blocks = map[ids.ID]*snowmanBlock{
-		lastAcceptedID: {params: ts.params},
+		lastAcceptedID: {t: ts},
 	}
 	ts.preferredHeights = make(map[uint64]ids.ID)
 	ts.preference = lastAcceptedID
@@ -162,8 +162,8 @@ func (ts *Topological) Add(blk Block) error {
 	// add the block as a child of its parent, and add the block to the tree
 	parentNode.AddChild(blk)
 	ts.blocks[blkID] = &snowmanBlock{
-		params: ts.params,
-		blk:    blk,
+		t:   ts,
+		blk: blk,
 	}
 
 	// If we are extending the preference, this is the new preference
@@ -278,7 +278,12 @@ func (ts *Topological) RecordPoll(ctx context.Context, voteBag bag.Bag[ids.ID])
 
 	// Runtime = |live set| ; Space = Constant
 	// Traverse from the preferred ID to the last accepted ancestor.
-	for block := startBlock; !block.Accepted(); {
+	//
+	// It is guaranteed that the first decided block we encounter is the last
+	// accepted block because the startBlock is the preferred block. The
+	// preferred block is guaranteed to either be the last accepted block or
+	// extend the accepted chain.
+	for block := startBlock; !block.Decided(); {
 		blkID := block.blk.ID()
 		ts.preferredIDs.Add(blkID)
 		ts.preferredHeights[block.blk.Height()] = blkID
@@ -349,7 +354,7 @@ func (ts *Topological) calculateInDegree(votes bag.Bag[ids.ID]) {
 		}
 
 		// If the vote is for the last accepted block, the vote is dropped
-		if votedBlock.Accepted() {
+		if votedBlock.Decided() {
 			continue
 		}
 
@@ -373,7 +378,7 @@ func (ts *Topological) calculateInDegree(votes bag.Bag[ids.ID]) {
 
 		// iterate through all the block's ancestors and set up the inDegrees of
 		// the blocks
-		for n := ts.blocks[parentID]; !n.Accepted(); n = ts.blocks[parentID] {
+		for n := ts.blocks[parentID]; !n.Decided(); n = ts.blocks[parentID] {
 			parentID = n.blk.Parent()
 
 			// Increase the inDegree by one
@@ -417,7 +422,7 @@ func (ts *Topological) pushVotes() []votes {
 
 		// If the block is accepted, then we don't need to push votes to the
 		// parent block
-		if block.Accepted() {
+		if block.Decided() {
 			continue
 		}