fix: log unexpected condition in peerWantManager.prepareSendWants()

internal/peermanager/peermanager.go

@@ -4,12 +4,15 @@ import (
 	"context"
 	"sync"
 
+	logging "github.com/ipfs/go-log"
 	"github.com/ipfs/go-metrics-interface"
 
 	cid "github.com/ipfs/go-cid"
 	peer "github.com/libp2p/go-libp2p-core/peer"
 )
 
+var log = logging.Logger("bs:peermgr")
+
 // PeerQueue provides a queue of messages to be sent for a single peer.
 type PeerQueue interface {
 	AddBroadcastWantHaves([]cid.Cid)

internal/peermanager/peerwantmanager.go

@@ -86,7 +86,17 @@ func (pwm *peerWantManager) prepareSendWants(p peer.ID, wantBlocks []cid.Cid, wa
 	resWantHvs := make([]cid.Cid, 0)
 
 	// Get the existing want-blocks and want-haves for the peer
-	if pws, ok := pwm.peerWants[p]; ok {
+	pws, ok := pwm.peerWants[p]
+
+	if !ok {
+		// In practice this should never happen:
+		// - PeerManager calls addPeer() as soon as the peer connects
+		// - PeerManager calls removePeer() as soon as the peer disconnects
+		// - All calls to PeerWantManager are locked
+		log.Errorf("prepareSendWants() called with peer %s but peer not found in peerWantManager", string(p))
+		return resWantBlks, resWantHvs
+	}
+
 	// Iterate over the requested want-blocks
 	for _, c := range wantBlocks {
 		// If the want-block hasn't been sent to the peer
@@ -116,7 +126,6 @@ func (pwm *peerWantManager) prepareSendWants(p peer.ID, wantBlocks []cid.Cid, wa
 			resWantHvs = append(resWantHvs, c)
 		}
 	}
-	}
 
 	return resWantBlks, resWantHvs
 }