Conpherence - kill race conditions around update

Summary:
Fixes T6713. The idea is to keep checking what's going on in the update paths that touch the DOM. If we're doing an update or should be doing a different update, then we bail early.

This is the type of code + testing that makes me dizzy after awhile, but I think it works...

Test Plan:
added a "forceStall" parameter to the column view controller, which when specified sleeps for seconds before returning. I then augmented the JS such that the "send message" code for the durable column would specifiy this parameter.

For actual testing, I then spammed the heck out of the durable column channel and saw each message only once. I also spammed the column, switched browsers to a user on the same thread in the normal "speedy" view, sent messages there, and also only received one copy

Reviewers: chad, epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T6713

Differential Revision: https://secure.phabricator.com/D12092

resources/celerity/map.php

@@ -352,7 +352,7 @@ return array(
     'rsrc/js/application/aphlict/behavior-aphlict-status.js' => 'ea681761',
     'rsrc/js/application/auth/behavior-persona-login.js' => '9414ff18',
     'rsrc/js/application/config/behavior-reorder-fields.js' => '14a827de',
-    'rsrc/js/application/conpherence/ConpherenceThreadManager.js' => 'cff1902b',
+    'rsrc/js/application/conpherence/ConpherenceThreadManager.js' => 'bbc850a4',
     'rsrc/js/application/conpherence/behavior-durable-column.js' => 'e975bd12',
     'rsrc/js/application/conpherence/behavior-menu.js' => 'c4151295',
     'rsrc/js/application/conpherence/behavior-pontificate.js' => '21ba5861',
@@ -517,7 +517,7 @@ return array(
     'conpherence-menu-css' => 'c6ac5299',
     'conpherence-message-pane-css' => '2526107d',
     'conpherence-notification-css' => '04a6e10a',
-    'conpherence-thread-manager' => 'cff1902b',
+    'conpherence-thread-manager' => 'bbc850a4',
     'conpherence-update-css' => '1099a660',
     'conpherence-widget-pane-css' => '3d575438',
     'differential-changeset-view-css' => '6a8b172a',
@@ -1684,6 +1684,16 @@ return array(
       'javelin-stratcom',
       'javelin-dom',
     ),
+    'bbc850a4' => array(
+      'javelin-dom',
+      'javelin-util',
+      'javelin-stratcom',
+      'javelin-install',
+      'javelin-workflow',
+      'javelin-router',
+      'javelin-behavior-device',
+      'javelin-vector',
+    ),
     'bbdf75ca' => array(
       'javelin-behavior',
       'javelin-dom',
@@ -1764,16 +1774,6 @@ return array(
       'javelin-stratcom',
       'phabricator-phtize',
     ),
-    'cff1902b' => array(
-      'javelin-dom',
-      'javelin-util',
-      'javelin-stratcom',
-      'javelin-install',
-      'javelin-workflow',
-      'javelin-router',
-      'javelin-behavior-device',
-      'javelin-vector',
-    ),
     'd19198c8' => array(
       'javelin-install',
       'javelin-dom',

src/applications/conpherence/controller/ConpherenceViewController.php

@@ -58,6 +58,9 @@ final class ConpherenceViewController extends
     $content['title'] = $title;
 
     if ($request->isAjax()) {
+      $content['threadID'] = $conpherence->getID();
+      $content['threadPHID'] = $conpherence->getPHID();
+      $content['latestTransactionID'] = $data['latest_transaction_id'];
       return id(new AphrontAjaxResponse())->setContent($content);
     }
 

webroot/rsrc/js/application/conpherence/ConpherenceThreadManager.js

@@ -167,6 +167,23 @@ JX.install('ConpherenceThreadManager', {
         }));
     },
 
+    _shouldUpdateDOM: function(r) {
+      if (this._updating &&
+          this._updating.threadPHID == this._loadedThreadPHID) {
+        // we have a different, more current update in progress so
+        // return early
+        if (r.latest_transaction_id < this._updating.knownID) {
+          return false;
+        }
+        // we need to let the update code handle things here
+        if (r.latest_transaction_id > this._updating.knownID) {
+          this._updating.knownID = r.latest_transaction_id;
+          return false;
+        }
+      }
+      return true;
+    },
+
     _updateThread: function() {
       var params = this._getParams({
         action: 'load',
@@ -177,7 +194,16 @@ JX.install('ConpherenceThreadManager', {
       var workflow = new JX.Workflow(uri)
         .setData(params)
         .setHandler(JX.bind(this, function(r) {
+          if (this._updating &&
+              this._updating.threadPHID == this._loadedThreadPHID) {
+            // we have a different, more current update in progress so
+            // return early
+            if (r.latest_transaction_id < this._updating.knownID) {
+              return;
+            }
+          }
           this._latestTransactionID = r.latest_transaction_id;
+          this._updating.knownID = r.latest_transaction_id;
           this._didUpdateThreadCallback(r);
         }));
 
@@ -191,10 +217,10 @@ JX.install('ConpherenceThreadManager', {
       };
       workflow.listen(stage, JX.bind(this, function() {
         // TODO - do we need to handle if we switch threads somehow?
-        var need_sync = (this._updating.knownID > this._latestTransactionID);
+        var need_sync = this._updating &&
-        this._updating = null;
+          (this._updating.knownID > this._latestTransactionID);
         if (need_sync) {
-          this._updateThread();
+          return this._updateThread();
         }
       }));
       workflow.start();
@@ -206,8 +232,10 @@ JX.install('ConpherenceThreadManager', {
       var workflow = new JX.Workflow.newFromLink(link)
         .setData(params)
         .setHandler(JX.bind(this, function(r) {
-          this._latestTransactionID = r.latest_transaction_id;
+          if (this._shouldUpdateDOM(r)) {
-          this._didUpdateWorkflowCallback(r);
+            this._latestTransactionID = r.latest_transaction_id;
+            this._didUpdateWorkflowCallback(r);
+          }
         }));
       this.syncWorkflow(workflow, params.stage);
     },
@@ -249,8 +277,10 @@ JX.install('ConpherenceThreadManager', {
 
       var workflow = JX.Workflow.newFromForm(form, params, keep_enabled)
         .setHandler(JX.bind(this, function(r) {
-          this._latestTransactionID = r.latest_transaction_id;
+          if (this._shouldUpdateDOM(r)) {
-          this._didSendMessageCallback(r);
+            this._latestTransactionID = r.latest_transaction_id;
+            this._didSendMessageCallback(r);
+          }
         }));
       this.syncWorkflow(workflow, 'finally');