Example V9 migration function

chain/consensus/filcns/upgrades.go

@@ -1431,9 +1431,28 @@ func upgradeActorsV8Common(
 	return newRoot, nil
 }
 
-func UpgradeActorsCode(ctx context.Context, sm *stmgr.StateManager, newActorsManifestCid cid.Cid, root cid.Cid, av actors.Version, oldStateTreeVersion types.StateTreeVersion, newStateTreeVersion types.StateTreeVersion) (cid.Cid, error) {
+func UpgradeActorsV9(ctx context.Context, sm *stmgr.StateManager, _ stmgr.MigrationCache, _ stmgr.ExecMonitor, root cid.Cid, _ abi.ChainEpoch, _ *types.TipSet) (cid.Cid, error) {
+	buf := blockstore.NewTieredBstore(sm.ChainStore().StateBlockstore(), blockstore.NewMemorySync())
+
+	// This MUST change for upgrade
+	av := actors.Version8
+	// This may change for upgrade
+	newStateTreeVersion := types.StateTreeVersion4
+
+	// ensure that the manifest is loaded in the blockstore
+	if err := bundle.FetchAndLoadBundles(ctx, buf, map[actors.Version]build.Bundle{
+		av: build.BuiltinActorReleases[av],
+	}); err != nil {
+		return cid.Undef, xerrors.Errorf("failed to load manifest bundle: %w", err)
+	}
+
+	newActorsManifestCid, ok := actors.GetManifest(av)
+	if !ok {
+		return cid.Undef, xerrors.Errorf("no manifest CID for v8 upgrade")
+	}
+
 	bstore := sm.ChainStore().StateBlockstore()
-	return LiteMigration(ctx, bstore, newActorsManifestCid, root, av, oldStateTreeVersion, newStateTreeVersion)
+	return LiteMigration(ctx, bstore, newActorsManifestCid, root, av, types.StateTreeVersion4, newStateTreeVersion)
 }
 
 func LiteMigration(ctx context.Context, bstore blockstore.Blockstore, newActorsManifestCid cid.Cid, root cid.Cid, av actors.Version, oldStateTreeVersion types.StateTreeVersion, newStateTreeVersion types.StateTreeVersion) (cid.Cid, error) {