Fix regression in Convertible module from v4.2.0 (#8786)

Merge pull request 8786

features/rendering.feature

@@ -207,3 +207,35 @@ Feature: Rendering
     And I should see "series named {{ site.title }}" in "_site/index.html"
     And I should see "{% link series/first-part.md %}" in "_site/index.html"
     And I should see "{% link series/last-part.md %}" in "_site/index.html"
+
+  Scenario: Render content of another page
+    Given I have an "index.md" page that contains "__Hello World__"
+    And I have an "about.md" page that contains "{{ page.name }}"
+    And I have a "test.json" file with content:
+      """
+      ---
+      ---
+
+      {
+        "hpages": [
+          {%- for page in site.html_pages %}
+          {
+            "url"    : {{ page.url     | jsonify }},
+            "name"   : {{ page.name    | jsonify }},
+            "path"   : {{ page.path    | jsonify }},
+            "title"  : {{ page.title   | jsonify }},
+            "layout" : {{ page.layout  | jsonify }},
+            "content": {{ page.content | jsonify }},
+            "excerpt": {{ page.excerpt | jsonify }}
+          }{% unless forloop.last %},{% endunless -%}
+          {% endfor %}
+        ]
+      }
+      """
+    When I run jekyll build
+    Then I should get a zero exit status
+    And the _site directory should exist
+    But I should not see "content\": \"{{ page.name }}" in "_site/test.json"
+    And I should not see "content\": \"__Hello World__" in "_site/test.json"
+    But I should see "content\": \"<p>about.md</p>" in "_site/test.json"
+    And I should see "content\": \"<p><strong>Hello World</strong></p>" in "_site/test.json"

lib/jekyll/convertible.rb

@@ -112,7 +112,11 @@ module Jekyll
     #
     # Returns the Hash representation of this Convertible.
     def to_liquid(attrs = nil)
-      further_data = attribute_hash(attrs || self.class::ATTRIBUTES_FOR_LIQUID)
+      further_data = \
+        (attrs || self.class::ATTRIBUTES_FOR_LIQUID).each_with_object({}) do |attribute, hsh|
+          hsh[attribute] = send(attribute)
+        end
+
       Utils.deep_merge_hashes defaults, Utils.deep_merge_hashes(data, further_data)
     end
 
@@ -246,13 +250,6 @@ module Jekyll
       @defaults ||= site.frontmatter_defaults.all(relative_path, type)
     end
 
-    def attribute_hash(attrs)
-      @attribute_hash ||= {}
-      @attribute_hash[attrs] ||= attrs.each_with_object({}) do |attribute, hsh|
-        hsh[attribute] = send(attribute)
-      end
-    end
-
     def no_layout?
       data["layout"] == "none"
     end