close session only when peer sessions are all closed

index.js

@@ -492,7 +492,7 @@ module.exports = class Hypercore extends EventEmitter {
     // check if there is still an active session
     if (this.sessions.length || this.state.active > 0) {
       // if this is the last session and we are auto closing, trigger that first to enforce error handling
-      if (this.sessions.length === 1 && this.state.active === 1 && this.autoClose) await this.sessions[0].close(err)
+      if (this.sessions.length === 1 && this.core.state.active === 1 && this.autoClose) await this.sessions[0].close(err)
       // emit "fake" close as this is a session
 
       this.emit('close', false)

lib/core.js

@@ -127,11 +127,13 @@ class SessionState {
 
     this.treeLength = treeLength
 
-    this.active = 1
+    this.active = 0
 
     this._onflush = null
     this._flushing = null
     this._activeBatch = null
+
+    this.ref()
   }
 
   get isSnapshot () {

lib/replicator.js

@@ -557,13 +557,12 @@ class Peer {
     const reopen = isRemote === true && this.remoteOpened === true && this.remoteDownloading === false &&
        this.remoteUploading === true && this.replicator.downloading === true
 
-    if (this.useSession && !reopen && --this.replicator._peerSessions === 0) {
-      this.replicator._closeSession()
-    }
-
     if (this.remoteOpened === false) {
       this.replicator._ifAvailable--
       this.replicator.updateAll()
+
+      if (this.useSession) this.replicator._closeSessionMaybe()
+
       return
     }
 
@@ -1776,6 +1775,12 @@ module.exports = class Replicator {
   }
 
   _addPeer (peer) {
+    if (peer.useSession) {
+      // session may have been unref'd underneath us
+      this.ensureSession()
+      this._peerSessions++
+    }
+
     this._hadPeers = true
     this.peers.push(peer)
     this.updatePeer(peer)
@@ -1799,6 +1804,11 @@ module.exports = class Replicator {
       this._clearRequest(peer, req)
     }
 
+    if (peer.useSession) {
+      this._peerSessions--
+      this._closeSessionMaybe()
+    }
+
     this.onpeerupdate(false, peer)
     this.updateAll()
   }
@@ -2275,7 +2285,9 @@ module.exports = class Replicator {
     this._maybeResolveIfAvailableRanges()
   }
 
-  _closeSession () {
+  _closeSessionMaybe () {
+    if (!this._hasSession || this._peerSessions > 0) return
+
     this._hasSession = false
     this.core.state.active--
 
@@ -2296,11 +2308,16 @@ module.exports = class Replicator {
     return this._attached.has(protomux)
   }
 
+  ensureSession () {
+    if (this._hasSession) return
+
+    this._hasSession = true
+    this.core.state.ref()
+  }
+
   attachTo (protomux, useSession) {
-    if (useSession && !this._hasSession) {
-      this._hasSession = true
-      this.core.state.ref()
-    }
+    if (this.core.state.closed) return
+    if (useSession) this.ensureSession()
 
     const makePeer = this._makePeer.bind(this, protomux, useSession)
 
@@ -2314,7 +2331,7 @@ module.exports = class Replicator {
       this._ifAvailable--
 
       if (opened && !this.destroyed) makePeer()
-      else if (useSession) this._closeSession()
+      else if (useSession) this._closeSessionMaybe()
       this._checkUpgradeIfAvailable()
     })
   }
@@ -2342,10 +2359,6 @@ module.exports = class Replicator {
   }
 
   _makePeer (protomux, useSession) {
-    if (useSession) {
-      this._peerSessions++
-    }
-
     const replicator = this
     if (protomux.opened({ protocol: 'hypercore/alpha', id: this.discoveryKey })) return onnochannel()
 
@@ -2385,10 +2398,7 @@ module.exports = class Replicator {
     return true
 
     function onnochannel () {
-      if (useSession && --replicator._peerSessions === 0) {
-        replicator._closeSession()
-      }
-
+      if (useSession) replicator._closeSessionMaybe()
       return false
     }
   }