From 88c104bb831597af6b95555a0f97e49268e1fe4b Mon Sep 17 00:00:00 2001
From: Robin Ward <robin.ward@gmail.com>
Date: Wed, 10 Feb 2016 13:40:31 -0500
Subject: [PATCH] FIX: Upwards scrolling was broken in a topic

---
 .../discourse/components/mount-widget.js.es6         | 12 +++++++++++-
 .../components/scrolling-post-stream.js.es6          |  8 +++-----
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/app/assets/javascripts/discourse/components/mount-widget.js.es6 b/app/assets/javascripts/discourse/components/mount-widget.js.es6
index d23485964f0..cd108d449dc 100644
--- a/app/assets/javascripts/discourse/components/mount-widget.js.es6
+++ b/app/assets/javascripts/discourse/components/mount-widget.js.es6
@@ -6,6 +6,7 @@ export default Ember.Component.extend({
   _rootNode: null,
   _timeout: null,
   _widgetClass: null,
+  _afterRender: null,
 
   init() {
     this._super();
@@ -24,7 +25,11 @@ export default Ember.Component.extend({
     Ember.run.cancel(this._timeout);
   },
 
-  queueRerender() {
+  queueRerender(callback) {
+    if (callback && !this._afterRender) {
+      this._afterRender = callback;
+    }
+
     Ember.run.scheduleOnce('render', this, this.rerenderWidget);
   },
 
@@ -41,6 +46,11 @@ export default Ember.Component.extend({
       this._rootNode = patch(this._rootNode, patches);
       this._tree = newTree;
       console.log('render: ', new Date().getTime() - t0);
+
+      if (this._afterRender) {
+        this._afterRender();
+        this._afterRender = null;
+      }
     }
   }
 
diff --git a/app/assets/javascripts/discourse/components/scrolling-post-stream.js.es6 b/app/assets/javascripts/discourse/components/scrolling-post-stream.js.es6
index 4489e5aa657..490ff3d0a35 100644
--- a/app/assets/javascripts/discourse/components/scrolling-post-stream.js.es6
+++ b/app/assets/javascripts/discourse/components/scrolling-post-stream.js.es6
@@ -77,7 +77,7 @@ export default MountWidget.extend({
     const posts = this.posts;
     if (onscreen.length) {
 
-      const refresh = () => this.queueRerender();
+      const refresh = cb => this.queueRerender(cb);
       const first = posts.objectAt(onscreen[0]);
       if (this._topVisible !== first) {
         this._topVisible = first;
@@ -89,10 +89,8 @@ export default MountWidget.extend({
         const distToElement = elemPos ? $body.scrollTop() - elemPos.top : 0;
 
         const topRefresh = () => {
-          refresh();
-
-          Ember.run.next(() => {
-            const $refreshedElem = $(elemId);
+          refresh(() => {
+            const $refreshedElem = $(`#${elemId}`);
 
             // Quickly going back might mean the element is destroyed
             const position = $refreshedElem.position();