[fix] #1214 accept closer heads

app/modules/ws2p/lib/WS2PCluster.ts

@@ -164,10 +164,12 @@ export class WS2PCluster {
       const sigOK = verify(head.message, head.sig, pub)
       const sigV2OK = (head.messageV2 !== undefined && head.sigV2 !== undefined) ? verify(head.messageV2, head.sigV2, pub):false
       if ((sigV2OK && sigOK) || sigOK) {
-        // Already known?
-        if (!this.headsCache[fullId] || this.headsCache[fullId].blockstamp !== blockstamp) {
-          // More recent?
-          if (!this.headsCache[fullId] || parseInt(this.headsCache[fullId].blockstamp) < parseInt(blockstamp)) {
+        // Already known or more recent or closer ?
+        const step = this.headsCache[fullId].step || 0
+        if (!this.headsCache[fullId] // unknow head
+          || parseInt(this.headsCache[fullId].blockstamp) < parseInt(blockstamp) // more recent head
+          || (head.step !== undefined && head.step < step && this.headsCache[fullId].blockstamp === blockstamp) // closer head
+        ) {
           // Check that issuer is a member and that the block exists
           const isAllowed = pub === this.server.conf.pair.pub || this.isConnectedKey(pub) || (await this.isMemberKey(pub))
           if (isAllowed) {
@@ -189,7 +191,6 @@ export class WS2PCluster {
             }
           }
         }
-        }
       } else {
         throw "HEAD_MESSAGE_WRONGLY_SIGNED"
       }