(core) Fix race condition in bundling actions for undo, when actions are submitted close together.

Summary:
The way linkId was set on actions to tie them together for undo bundling was
incorrect. This diff fixes it by moves the setting of linkIds to Sharing.ts,
which already serializes the processing of actions.

Test Plan: Added a test case for submitting actions together while bundling (which fails without this change).

Reviewers: paulfitz

Reviewed By: paulfitz

Differential Revision: https://phab.getgrist.com/D2716

app/server/lib/ActiveDoc.ts

@@ -14,6 +14,7 @@ import flatten = require('lodash/flatten');
 import remove = require('lodash/remove');
 import zipObject = require('lodash/zipObject');
 import * as moment from 'moment-timezone';
+import fetch from 'node-fetch';
 import * as tmp from 'tmp';
 
 import {getEnvContent, LocalActionBundle} from 'app/common/ActionBundle';
@@ -60,7 +61,6 @@ import {expandQuery} from './ExpandedQuery';
 import {GranularAccess} from './GranularAccess';
 import {OnDemandActions} from './OnDemandActions';
 import {findOrAddAllEnvelope, Sharing} from './Sharing';
-import fetch from 'node-fetch';
 
 bluebird.promisifyAll(tmp);
 
@@ -732,11 +732,8 @@ export class ActiveDoc extends EventEmitter {
     // Be careful not to sneak into user action queue before Calculate action, otherwise
     // there'll be a deadlock.
     await this.waitForInitialization();
-    const newOptions = {linkId: docSession.linkId, ...options};
     // Granular access control implemented in _applyUserActions.
-    const result: ApplyUAResult = await this._applyUserActions(docSession, actions, newOptions);
-    docSession.linkId = docSession.shouldBundleActions ? result.actionNum : 0;
-    return result;
+    return await this._applyUserActions(docSession, actions, options);
   }
 
   /**
@@ -913,12 +910,13 @@ export class ActiveDoc extends EventEmitter {
     const permitKey = await permitStore.setPermit({docId: forkIds.docId,
                                                    otherDocId: this.docName});
     try {
-      const url = await this._docManager.gristServer.getHomeUrlByDocId(forkIds.docId, `/api/docs/${forkIds.docId}/create-fork`);
+      const url = await this._docManager.gristServer.getHomeUrlByDocId(
+        forkIds.docId, `/api/docs/${forkIds.docId}/create-fork`);
       const resp = await fetch(url, {
         method: 'POST',
         body: JSON.stringify({ srcDocId: this.docName }),
         headers: {
-          Permit: permitKey,
+          'Permit': permitKey,
           'Content-Type': 'application/json',
         },
       });

app/server/lib/Sharing.ts

@@ -209,6 +209,10 @@ export class Sharing {
                                    branch: Branch, docSession: OptDocSession|null): Promise<UserResult> {
     const client = docSession && docSession.client;
 
+    if (docSession?.linkId) {
+      info.linkId = docSession.linkId;
+    }
+
     const {sandboxActionBundle, undo, docActions} =
       await this._modificationLock.runExclusive(() => this._applyActionsToDataEngine(docSession, userActions));
 
@@ -271,12 +275,6 @@ export class Sharing {
     }
     await this._activeDoc.processActionBundle(ownActionBundle);
 
-    // In the future, we'll save (and share) the result of applying one bundle of UserActions
-    // as a single ActionBundle with one actionNum. But the old ActionLog saves on UserAction
-    // per actionNum, using linkId to "bundle" them for the purpose of undo-redo. We simulate
-    // it here by breaking up ActionBundle into as many old-style ActionGroups as there are
-    // UserActions, and associating all DocActions with the first of these ActionGroups.
-
     // Broadcast the action to connected browsers.
     const actionGroup = asActionGroup(this._actionHistory, localActionBundle, {
       client,
@@ -295,6 +293,9 @@ export class Sharing {
     } finally {
       await this._activeDoc.finishedActions();
     }
+    if (docSession) {
+      docSession.linkId = docSession.shouldBundleActions ? localActionBundle.actionNum : 0;
+    }
     return {
       actionNum: localActionBundle.actionNum,
       retValues: sandboxActionBundle.retValues,