From 0e781be17713086f211c69005852be1918b834a4 Mon Sep 17 00:00:00 2001
From: Matt Joiner <anacrolix@gmail.com>
Date: Tue, 27 Feb 2024 23:30:53 +1100
Subject: [PATCH] Get infohash selection working when adding v2 torrents

---
 spec.go    | 7 ++++++-
 torrent.go | 9 ++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/spec.go b/spec.go
index f1ef584e..29d30adc 100644
--- a/spec.go
+++ b/spec.go
@@ -69,13 +69,18 @@ func TorrentSpecFromMetaInfoErr(mi *metainfo.MetaInfo) (*TorrentSpec, error) {
 	if err != nil {
 		err = fmt.Errorf("unmarshalling info: %w", err)
 	}
+	v1Ih := mi.HashInfoBytes()
 	var v2Infohash g.Option[infohash_v2.T]
 	if info.HasV2() {
 		v2Infohash.Set(infohash_v2.HashBytes(mi.InfoBytes))
+		if !info.HasV1() {
+			v1Ih = v2Infohash.Value.ToShort()
+		}
 	}
+
 	return &TorrentSpec{
 		Trackers:    mi.UpvertedAnnounceList(),
-		InfoHash:    mi.HashInfoBytes(),
+		InfoHash:    v1Ih,
 		InfoHashV2:  v2Infohash,
 		PieceLayers: mi.PieceLayers,
 		InfoBytes:   mi.InfoBytes,
diff --git a/torrent.go b/torrent.go
index e2afb3e3..8416e4ba 100644
--- a/torrent.go
+++ b/torrent.go
@@ -8,6 +8,7 @@ import (
 	"errors"
 	"fmt"
 	"github.com/anacrolix/torrent/merkle"
+	"github.com/anacrolix/torrent/types/infohash"
 	infohash_v2 "github.com/anacrolix/torrent/types/infohash-v2"
 	"io"
 	"math/rand"
@@ -538,13 +539,19 @@ func (t *Torrent) onSetInfo() {
 
 // Called when metadata for a torrent becomes available.
 func (t *Torrent) setInfoBytesLocked(b []byte) error {
-	if metainfo.HashBytes(b) != t.infoHash {
+	v2Hash := infohash_v2.HashBytes(b)
+	v1Hash := infohash.HashBytes(b)
+	v2Short := v2Hash.ToShort()
+	if v2Short != t.infoHash && v1Hash != t.infoHash {
 		return errors.New("info bytes have wrong hash")
 	}
 	var info metainfo.Info
 	if err := bencode.Unmarshal(b, &info); err != nil {
 		return fmt.Errorf("error unmarshalling info bytes: %s", err)
 	}
+	if info.HasV2() {
+		t.infoHashV2.Set(v2Hash)
+	}
 	t.metadataBytes = b
 	t.metadataCompletedChunks = nil
 	if t.info != nil {
-- 
2.44.0