From 6ded29a7d8081a89d605eb77238b99f1d423efb9 Mon Sep 17 00:00:00 2001
From: Alberto Benegiamo <alberto.benegiamo@gmail.com>
Date: Wed, 1 Nov 2023 23:59:36 +0100
Subject: [PATCH] wip: adding UTs

---
 .../state_sync_block_backfilling_test.go         | 11 +++++++----
 vms/proposervm/state_syncable_vm.go              | 16 +++++++++++++---
 2 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/vms/proposervm/state_sync_block_backfilling_test.go b/vms/proposervm/state_sync_block_backfilling_test.go
index a7e5ebb3f4d4..d73895c4e7bd 100644
--- a/vms/proposervm/state_sync_block_backfilling_test.go
+++ b/vms/proposervm/state_sync_block_backfilling_test.go
@@ -35,6 +35,7 @@ func TestBlockBackfillEnabled(t *testing.T) {
 
 	// 1. Accept a State summary
 	var (
+		forkHeight                 = uint64(100)
 		stateSummaryHeight         = uint64(2023)
 		proVMParentStateSummaryBlk = ids.GenerateTestID()
 	)
@@ -51,7 +52,7 @@ func TestBlockBackfillEnabled(t *testing.T) {
 		HeightV: innerSummary.Height(),
 		BytesV:  []byte("inner state synced block"),
 	}
-	stateSummary := createTestStateSummary(t, vm, proVMParentStateSummaryBlk, innerVM, innerSummary, innerStateSyncedBlk)
+	stateSummary := createTestStateSummary(t, vm, proVMParentStateSummaryBlk, forkHeight, innerVM, innerSummary, innerStateSyncedBlk)
 
 	// Block backfilling not enabled before state sync is accepted
 	ctx := context.Background()
@@ -115,7 +116,8 @@ func TestBlockBackfill(t *testing.T) {
 	}()
 
 	var (
-		blkCount           = 1
+		forkHeight         = uint64(100)
+		blkCount           = 10
 		startBlkHeight     = uint64(1492)
 		proBlks, innerBlks = createTestBlocks(t, vm, blkCount, startBlkHeight)
 
@@ -137,7 +139,7 @@ func TestBlockBackfill(t *testing.T) {
 		HeightV: innerSummary.Height(),
 		BytesV:  []byte("inner state synced block"),
 	}
-	stateSummary := createTestStateSummary(t, vm, proTopBlk.ID(), innerVM, innerSummary, innerStateSyncedBlk)
+	stateSummary := createTestStateSummary(t, vm, proTopBlk.ID(), forkHeight, innerVM, innerSummary, innerStateSyncedBlk)
 
 	innerSummary.AcceptF = func(ctx context.Context) (block.StateSyncMode, error) {
 		return block.StateSyncStatic, nil
@@ -275,6 +277,7 @@ func createTestStateSummary(
 	t *testing.T,
 	vm *VM,
 	proVMParentStateSummaryBlk ids.ID,
+	forkHeight uint64,
 	innerVM *fullVM,
 	innerSummary *block.TestStateSummary,
 	innerBlk *snowman.TestBlock,
@@ -291,7 +294,7 @@ func createTestStateSummary(
 	)
 	require.NoError(err)
 
-	statelessSummary, err := summary.Build(innerSummary.Height()-1, slb.Bytes(), innerSummary.Bytes())
+	statelessSummary, err := summary.Build(forkHeight, slb.Bytes(), innerSummary.Bytes())
 	require.NoError(err)
 
 	innerVM.ParseStateSummaryF = func(ctx context.Context, summaryBytes []byte) (block.StateSummary, error) {
diff --git a/vms/proposervm/state_syncable_vm.go b/vms/proposervm/state_syncable_vm.go
index 88b7825bb341..c90371031ab1 100644
--- a/vms/proposervm/state_syncable_vm.go
+++ b/vms/proposervm/state_syncable_vm.go
@@ -6,8 +6,10 @@ package proposervm
 import (
 	"context"
 	"fmt"
+	"sort"
 
 	"go.uber.org/zap"
+	"golang.org/x/exp/maps"
 
 	"github.com/ava-labs/avalanchego/database"
 	"github.com/ava-labs/avalanchego/ids"
@@ -176,7 +178,7 @@ func (vm *VM) BackfillBlocksEnabled(ctx context.Context) (ids.ID, uint64, error)
 
 func (vm *VM) BackfillBlocks(ctx context.Context, blksBytes [][]byte) (ids.ID, uint64, error) {
 	var (
-		blks           = make([]Block, 0, len(blksBytes))
+		blks           = make(map[uint64]Block)
 		innerBlksBytes = make([][]byte, 0, len(blksBytes))
 	)
 
@@ -188,7 +190,7 @@ func (vm *VM) BackfillBlocks(ctx context.Context, blksBytes [][]byte) (ids.ID, u
 
 		// TODO: introduce validation
 
-		blks = append(blks, blk)
+		blks[blk.Height()] = blk
 		innerBlksBytes = append(innerBlksBytes, blk.getInnerBlk().Bytes())
 	}
 
@@ -198,7 +200,15 @@ func (vm *VM) BackfillBlocks(ctx context.Context, blksBytes [][]byte) (ids.ID, u
 		// Find out which blocks have been accepted and store them.
 		// Should the process err while looping there will be innerVM blocks not indexed by proposerVM. Repair will be
 		// carried out upon restart.
-		for _, blk := range blks {
+
+		// Make sure to sort blocks by height to accept them in the right order
+		blkHeights := maps.Keys(blks)
+		sort.Slice(blkHeights, func(i, j int) bool {
+			return blkHeights[i] < blkHeights[j] // sort in ascending order
+		})
+
+		for _, h := range blkHeights {
+			blk := blks[h]
 			_, err := vm.ChainVM.GetBlock(ctx, blk.getInnerBlk().ID())
 			if err != nil {
 				continue