feat: hamt-type assertations

tooling/car/unixfs.go

@@ -17,6 +17,7 @@ import (
 	"github.com/ipfs/boxo/blockservice"
 	"github.com/ipfs/boxo/ipld/car/v2/blockstore"
 	"github.com/ipfs/boxo/ipld/merkledag"
+	"github.com/ipfs/boxo/ipld/unixfs"
 	"github.com/ipfs/boxo/ipld/unixfs/hamt"
 	uio "github.com/ipfs/boxo/ipld/unixfs/io"
 	"github.com/ipfs/go-cid"
@@ -228,6 +229,26 @@ func (d *UnixfsDag) MustGetCIDsInHAMTTraversal(path []string, child string) []st
 	tracker := dservTrackingWrapper{
 		DAGService: node.dsvc,
 	}
+
+	// Do some assertations to ensure that the HAMT is well-formed.
+	pbnd, ok := node.node.(*merkledag.ProtoNode)
+	if !ok {
+		panic(merkledag.ErrNotProtobuf)
+	}
+
+	fsn, err := unixfs.FSNodeFromBytes(pbnd.Data())
+	if err != nil {
+		panic(err)
+	}
+
+	if fsn.Type() != unixfs.THAMTShard {
+		panic(fmt.Errorf("node was not a dir shard"))
+	}
+
+	if fsn.HashType() != hamt.HashMurmur3 {
+		panic(fmt.Errorf("only murmur3 supported as hash function"))
+	}
+
 	h, err := hamt.NewHamtFromDag(&tracker, node.node)
 	if err != nil {
 		panic(err)