Merge pull request #290 from yarolegovich/yarolegovich/fix-doc-sync-o…

…n-connect

fix: peer doesn't receive a document on connecting with another peer

packages/automerge-repo/src/synchronizer/DocSynchronizer.ts

@@ -227,8 +227,8 @@ export class DocSynchronizer extends Synchronizer {
   }
 
   beginSync(peerIds: PeerId[]) {
-    const newPeers = new Set(
-      peerIds.filter(peerId => !this.#peers.includes(peerId))
+    const noPeersWithDocument = peerIds.every(
+      (peerId) => this.#peerDocumentStatuses[peerId] in ["unavailable", "wants"]
     )
 
     // At this point if we don't have anything in our storage, we need to use an empty doc to sync
@@ -242,7 +242,7 @@ export class DocSynchronizer extends Synchronizer {
         this.#checkDocUnavailable()
 
         const wasUnavailable = doc === undefined
-        if (wasUnavailable && newPeers.size == 0) {
+        if (wasUnavailable && noPeersWithDocument) {
           return
         }
 

packages/automerge-repo/test/Repo.test.ts

@@ -3,7 +3,7 @@ import { MessageChannelNetworkAdapter } from "../../automerge-repo-network-messa
 import assert from "assert"
 import * as Uuid from "uuid"
 import { describe, expect, it } from "vitest"
-import { READY } from "../src/DocHandle.js"
+import { HandleState, READY } from "../src/DocHandle.js"
 import { parseAutomergeUrl } from "../src/AutomergeUrl.js"
 import {
   generateAutomergeUrl,
@@ -1023,6 +1023,37 @@ describe("Repo", () => {
     })
   })
 
+
+  it('peer receives a document when connection is recovered', async () => {
+    const alice = "alice" as PeerId;
+    const bob = "bob" as PeerId;
+    const [aliceAdapter, bobAdapter] = DummyNetworkAdapter.createConnectedPair();
+    const aliceRepo = new Repo({
+      network: [aliceAdapter],
+      peerId: alice
+    })
+    const bobRepo = new Repo({
+      network: [bobAdapter],
+      peerId: bob
+    })
+
+    const aliceDoc = aliceRepo.create();
+    aliceDoc.change((doc: any) => doc.text = 'Hello world');
+
+    const bobDoc = bobRepo.find(aliceDoc.url);
+    bobDoc.unavailable()
+    await bobDoc.whenReady([HandleState.UNAVAILABLE]);
+
+    aliceAdapter.peerCandidate(bob);
+    // Bob isn't yet connected to Alice and can't respond to her sync message
+    await pause(100);
+    bobAdapter.peerCandidate(alice);
+
+    await bobDoc.whenReady([HandleState.READY]);
+
+    assert.equal(bobDoc.isReady(), true);
+  });
+
   describe("with peers (mesh network)", () => {
     const setup = async () => {
       // Set up three repos; connect Alice to Bob, Bob to Charlie, and Alice to Charlie

packages/automerge-repo/test/helpers/DummyNetworkAdapter.ts

@@ -1,21 +1,53 @@
-import { NetworkAdapter } from "../../src/index.js"
+import { pause } from "../../src/helpers/pause.js";
+import { Message, NetworkAdapter, PeerId } from "../../src/index.js"
 
 export class DummyNetworkAdapter extends NetworkAdapter {
   #startReady: boolean
+  #sendMessage?: SendMessageFn;
 
-  constructor({ startReady = true }: Options = {}) {
+  constructor(opts: Options = {startReady: true}) {
     super()
-    this.#startReady = startReady
+    this.#startReady = opts.startReady;
+    this.#sendMessage = opts.sendMessage;
   }
-  send() {}
+
   connect(_: string) {
     if (this.#startReady) {
       this.emit("ready", { network: this })
     }
   }
+
   disconnect() {}
+
+  peerCandidate(peerId: PeerId) {
+    this.emit('peer-candidate', { peerId, peerMetadata: {} });
+  }
+
+  override send(message: Message) {
+    this.#sendMessage?.(message);
+  }
+
+  receive(message: Message) {
+    this.emit('message', message);
+  }
+
+  static createConnectedPair() {
+    const adapter1: DummyNetworkAdapter = new DummyNetworkAdapter({
+      startReady: true,
+      sendMessage: (message: Message) => pause(10).then(() => adapter2.receive(message)),
+    });
+    const adapter2: DummyNetworkAdapter = new DummyNetworkAdapter({
+      startReady: true,
+      sendMessage: (message: Message) => pause(10).then(() => adapter1.receive(message)),
+    });
+
+    return [adapter1, adapter2];
+  }
 }
 
+type SendMessageFn = (message: Message) => void;
+
 type Options = {
-  startReady?: boolean
+  startReady?: boolean;
+  sendMessage?: SendMessageFn;
 }