[FIX] session: avoid concurrent updates

Steps to reproduce (in odoo)
- Open a spreadsheet
- do something such that there's a least one revisions
- leave the spreadsheet

=> non-deterministic concurrent update because we save the thumbnail and we
snapshot at the same time.

I'm able to reproduce more when my laptop power setting is on "performance"
compared to "balanced"

With this commit `leaveSession` is now asynchronous and returns a promise
which resolves after the snapshot was done.
It allows to await this promise to trigger other RPC updating the same
record.

closes #4929

Task: 4080148
X-original-commit: ac3a12c
Signed-off-by: Pierre Rousseau (pro) <[email protected]>
Signed-off-by: Lucas Lefèvre (lul) <[email protected]>

src/collaborative/local_transport_service.ts

@@ -8,7 +8,7 @@ import {
 export class LocalTransportService implements TransportService<CollaborationMessage> {
   private listeners: { id: UID; callback: NewMessageCallback }[] = [];
 
-  sendMessage(message: CollaborationMessage) {
+  async sendMessage(message: CollaborationMessage) {
     for (const { callback } of this.listeners) {
       callback(message);
     }

src/collaborative/session.ts

@@ -165,9 +165,9 @@ export class Session extends EventBus<CollaborativeEvent> {
   /**
    * Notify the server that the user client left the collaborative session
    */
-  leave(data: Lazy<WorkbookData>) {
+  async leave(data: Lazy<WorkbookData>) {
     if (Object.keys(this.clients).length === 1 && this.processedRevisions.size) {
-      this.snapshot(data());
+      await this.snapshot(data());
     }
     delete this.clients[this.clientId];
     this.transportService.leave(this.clientId);
@@ -181,12 +181,12 @@ export class Session extends EventBus<CollaborativeEvent> {
   /**
    * Send a snapshot of the spreadsheet to the collaboration server
    */
-  snapshot(data: WorkbookData) {
+  async snapshot(data: WorkbookData) {
     if (this.pendingMessages.length !== 0) {
       return;
     }
     const snapshotId = this.uuidGenerator.uuidv4();
-    this.transportService.sendMessage({
+    await this.transportService.sendMessage({
       type: "SNAPSHOT",
       nextRevisionId: snapshotId,
       serverRevisionId: this.serverRevisionId,

src/model.ts

@@ -302,8 +302,8 @@ export class Model extends EventBus<any> implements CommandDispatcher {
     this.session.join(this.config.client);
   }
 
-  leaveSession() {
-    this.session.leave(lazy(() => this.exportData()));
+  async leaveSession() {
+    await this.session.leave(lazy(() => this.exportData()));
   }
 
   private setupUiPlugin(Plugin: UIPluginConstructor) {

src/types/collaborative/transport_service.ts

@@ -88,7 +88,7 @@ export interface TransportService<T = any> {
   /**
    * Send a message to all clients
    */
-  sendMessage: (message: T) => void;
+  sendMessage: (message: T) => Promise<void>;
   /**
    * Register a callback function which will be called each time
    * a new message is received.

tests/__mocks__/transport_service.ts

@@ -18,7 +18,7 @@ export class MockTransportService implements TransportService<CollaborationMessa
     this.listeners.push({ id, callback });
   }
 
-  sendMessage(message: CollaborationMessage) {
+  async sendMessage(message: CollaborationMessage) {
     const msg: CollaborationMessage = deepCopy(message);
     switch (msg.type) {
       case "REMOTE_REVISION":

tests/collaborative/collaborative_session.test.ts

@@ -6,6 +6,7 @@ import { buildRevisionLog } from "../../src/history/factory";
 import { Client, CommandResult, WorkbookData } from "../../src/types";
 import { MockTransportService } from "../__mocks__/transport_service";
 import { selectCell, setCellContent } from "../test_helpers/commands_helpers";
+import { nextTick } from "../test_helpers/helpers";
 
 describe("Collaborative session", () => {
   let transport: MockTransportService;
@@ -82,7 +83,7 @@ describe("Collaborative session", () => {
     });
   });
 
-  test("do not snapshot when leaving if there are pending change", () => {
+  test("do not snapshot when leaving if there are pending change", async () => {
     const model = new Model(
       {},
       {
@@ -98,6 +99,7 @@ describe("Collaborative session", () => {
       // and leave before receiving the acknowledgement
       model.leaveSession();
     });
+    await nextTick();
     expect(spy).toHaveBeenCalledTimes(2);
     expect(spy).toHaveBeenCalledWith(expect.objectContaining({ type: "REMOTE_REVISION" }));
     expect(spy).toHaveBeenCalledWith(expect.objectContaining({ type: "CLIENT_LEFT" }));