From 67904e849d6d0575c8f9e5d1d24852d37343030b Mon Sep 17 00:00:00 2001
From: Jeff Kolesky <jeff@kolesky.com>
Date: Tue, 1 Mar 2016 12:05:49 -0800
Subject: [PATCH] Ensures related_posts are only set for a post

Prior to this change, the related posts for the most recently rendered post
stayed set on the `site` object. This could result in pages that showed related
posts even when the page represented an entire collection of posts, such as on
an index page.  This change restores the functionality from Jekyll V2.
---
 features/create_sites.feature | 17 +++++++++++++++++
 lib/jekyll/renderer.rb        |  2 ++
 2 files changed, 19 insertions(+)

diff --git a/features/create_sites.feature b/features/create_sites.feature
index 031fa434..c1f75931 100644
--- a/features/create_sites.feature
+++ b/features/create_sites.feature
@@ -186,3 +186,20 @@ Feature: Create sites
     Then I should get a zero exit status
     And the _site directory should exist
     And the "_site/2020/12/31/entry1.html" file should exist
+
+  Scenario: Basic site with layouts, posts and related posts
+    Given I have a _layouts directory
+    And I have a page layout that contains "Page {{ page.title }}: {{ content }}"
+    And I have a post layout that contains "Post {{ page.title }}: {{ content }}Related posts: {{ site.related_posts | size }}"
+    And I have an "index.html" page with layout "page" that contains "Site contains {{ site.pages.size }} pages and {{ site.posts.size }} posts; Related posts: {{ site.related_posts | size }}"
+    And I have a _posts directory
+    And I have the following posts:
+      | title  | date       | layout | content             |
+      | entry1 | 2009-03-27 | post   | content for entry1. |
+      | entry2 | 2009-04-27 | post   | content for entry2. |
+    When I run jekyll build
+    Then I should get a zero exit status
+    And the _site directory should exist
+    And I should see "Page : Site contains 1 pages and 2 posts; Related posts: 0" in "_site/index.html"
+    And I should see "Post entry1: <p>content for entry1.</p>\nRelated posts: 1" in "_site/2009/03/27/entry1.html"
+    And I should see "Post entry2: <p>content for entry2.</p>\nRelated posts: 1" in "_site/2009/04/27/entry2.html"
diff --git a/lib/jekyll/renderer.rb b/lib/jekyll/renderer.rb
index 09815a60..7d20d452 100644
--- a/lib/jekyll/renderer.rb
+++ b/lib/jekyll/renderer.rb
@@ -40,6 +40,8 @@ module Jekyll
 
       if document.is_a?(Document) && document.collection.label == 'posts'
         payload['site']['related_posts'] = document.related_posts
+      else
+        payload['site']['related_posts'] = nil
       end
 
       # render and transform content (this becomes the final content of the object)