From dfe1a9bae5ceeba7f1f649d10559d59d6c89e3ae Mon Sep 17 00:00:00 2001
From: Toby Zerner <toby.zerner@gmail.com>
Date: Tue, 23 Jun 2015 10:30:06 +0930
Subject: [PATCH] Gracefully handle discussions with no posts

Although this should never happen
---
 framework/core/js/forum/src/components/post-scrubber.js | 6 +++---
 framework/core/js/forum/src/components/post-stream.js   | 8 ++++----
 framework/core/js/lib/models/discussion.js              | 2 +-
 framework/core/src/Api/Serializers/BaseSerializer.php   | 2 +-
 4 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/framework/core/js/forum/src/components/post-scrubber.js b/framework/core/js/forum/src/components/post-scrubber.js
index 506eaa6e6..032761d46 100644
--- a/framework/core/js/forum/src/components/post-scrubber.js
+++ b/framework/core/js/forum/src/components/post-scrubber.js
@@ -135,7 +135,7 @@ export default class PostScrubber extends Component {
     // seen if the browser were scrolled right up to the top of the page,
     // and the viewport had a height of 0.
     var $items = stream.$('> .item[data-index]');
-    var index = $items.first().data('index');
+    var index = $items.first().data('index') || 0;
     var visible = 0;
     var period = '';
 
@@ -262,7 +262,7 @@ export default class PostScrubber extends Component {
     var percentPerPost = this.percentPerPost();
     var index = this.index();
     var count = this.count();
-    var visible = this.visible();
+    var visible = this.visible() || 1;
 
     var $scrubber = this.$();
     $scrubber.find('.index').text(formatNumber(this.visibleIndex()));
@@ -292,7 +292,7 @@ export default class PostScrubber extends Component {
    */
   percentPerPost() {
     var count = this.count() || 1;
-    var visible = this.visible();
+    var visible = this.visible() || 1;
 
     // To stop the slider of the scrollbar from getting too small when there
     // are many posts, we define a minimum percentage height for the slider
diff --git a/framework/core/js/forum/src/components/post-stream.js b/framework/core/js/forum/src/components/post-stream.js
index f0d369281..754511bdc 100644
--- a/framework/core/js/forum/src/components/post-stream.js
+++ b/framework/core/js/forum/src/components/post-stream.js
@@ -128,7 +128,7 @@ class PostStream extends mixin(Component, evented) {
    */
   setup(posts) {
     this.posts = posts;
-    this.visibleStart = this.discussion.postIds().indexOf(posts[0].id());
+    this.visibleStart = posts.length ? this.discussion.postIds().indexOf(posts[0].id()) : 0;
     this.visibleEnd = this.visibleStart + posts.length;
   }
 
@@ -137,7 +137,7 @@ class PostStream extends mixin(Component, evented) {
    */
   clear(start, end) {
     this.visibleStart = start || 0;
-    this.visibleEnd = end || this.constructor.loadCount;
+    this.visibleEnd = Math.min(this.count(), end || this.constructor.loadCount);
     this.posts = [];
     for (var i = this.visibleStart; i < this.visibleEnd; i++) {
       this.posts.push(null);
@@ -234,7 +234,7 @@ class PostStream extends mixin(Component, evented) {
     if (this.visibleStart > 0) {
       var $item = this.$('.item[data-index='+this.visibleStart+']');
 
-      if ($item.offset().top > viewportTop - loadAheadDistance) {
+      if ($item.length && $item.offset().top > viewportTop - loadAheadDistance) {
         this.loadPrevious();
       }
     }
@@ -242,7 +242,7 @@ class PostStream extends mixin(Component, evented) {
     if (this.visibleEnd < this.count()) {
       var $item = this.$('.item[data-index='+(this.visibleEnd - 1)+']');
 
-      if ($item.offset().top + $item.outerHeight(true) < viewportTop + viewportHeight + loadAheadDistance) {
+      if ($item.length && $item.offset().top + $item.outerHeight(true) < viewportTop + viewportHeight + loadAheadDistance) {
         this.loadNext();
       }
     }
diff --git a/framework/core/js/lib/models/discussion.js b/framework/core/js/lib/models/discussion.js
index b03461cbe..fe39bbf4a 100644
--- a/framework/core/js/lib/models/discussion.js
+++ b/framework/core/js/lib/models/discussion.js
@@ -58,7 +58,7 @@ Discussion.prototype.canRename = Model.prop('canRename');
 Discussion.prototype.canDelete = Model.prop('canDelete');
 
 Discussion.prototype.commentsCount = Model.prop('commentsCount');
-Discussion.prototype.repliesCount = computed('commentsCount', commentsCount => commentsCount - 1);
+Discussion.prototype.repliesCount = computed('commentsCount', commentsCount => Math.max(0, commentsCount - 1));
 
 Discussion.prototype.posts = Model.many('posts');
 Discussion.prototype.postIds = function() { return this.data().links.posts.linkage.map((link) => link.id); };
diff --git a/framework/core/src/Api/Serializers/BaseSerializer.php b/framework/core/src/Api/Serializers/BaseSerializer.php
index d7ebb33f4..dc3d1a9b4 100644
--- a/framework/core/src/Api/Serializers/BaseSerializer.php
+++ b/framework/core/src/Api/Serializers/BaseSerializer.php
@@ -58,7 +58,7 @@ abstract class BaseSerializer extends SerializerAbstract
                     $data = $model->getRelation($relation);
                 } elseif ($many) {
                     $relationIds = $relation.'_ids';
-                    $data = $model->$relationIds ?: $model->$relation()->lists('id');
+                    $data = isset($model->$relationIds) ? $model->$relationIds : $model->$relation()->lists('id');
                 } else {
                     $relationId = $relation.'_id';
                     $data = $model->$relationId;