peer checks replicator state before any db reads

lib/replicator.js

@@ -525,6 +525,8 @@ class Peer {
   }
 
   onopen ({ seeks, capability }) {
+    if (this.replicator.destroyed) return
+
     const expected = caps.replicate(this.stream.isInitiator === false, this.replicator.key, this.stream.handshakeHash)
 
     if (b4a.equals(capability, expected) !== true) { // TODO: change this to a rejection instead, less leakage
@@ -605,6 +607,8 @@ class Peer {
   }
 
   async onsync ({ fork, length, remoteLength, canUpgrade, uploading, downloading, hasManifest }) {
+    if (this.replicator.destroyed) return
+
     const lengthChanged = length !== this.remoteLength
     const sameFork = fork === this.core.tree.fork
 
@@ -669,6 +673,8 @@ class Peer {
 
   // Safe to call in the background - never fails
   async _canUpgrade (remoteLength, remoteFork) {
+    if (this.replicator.destroyed) return false
+
     if (remoteFork !== this.core.tree.fork) return false
 
     if (remoteLength === 0) return true
@@ -708,6 +714,8 @@ class Peer {
   async onrequest (msg) {
     this.tracer.trace('onrequest', msg)
 
+    if (this.replicator.destroyed) return
+
     const size = this.remoteRequests.size
     this.remoteRequests.set(msg.id, msg)
 
@@ -848,6 +856,8 @@ class Peer {
   async ondata (data) {
     this.tracer.trace('ondata', data)
 
+    if (this.replicator.destroyed) return
+
     // always allow a fork conflict proof to be sent
     if (data.request === 0 && data.upgrade && data.upgrade.start === 0) {
       if (await this.core.checkConflict(data, this)) return