From 9c0c518d524463c9915cd35aa172134a4f7875cf Mon Sep 17 00:00:00 2001
From: Ashwin Maroli <ashmaroli@users.noreply.github.com>
Date: Mon, 13 Apr 2020 13:22:54 +0530
Subject: [PATCH] Cache URLFilter results of string inputs per site (#7990)

Merge pull request 7990
---
 lib/jekyll/filters/url_filters.rb | 28 ++++++++++++++++++++++------
 lib/jekyll/site.rb                |  3 ++-
 test/test_filters.rb              |  1 +
 3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/lib/jekyll/filters/url_filters.rb b/lib/jekyll/filters/url_filters.rb
index 5d984096160..a7dd4dbb37b 100644
--- a/lib/jekyll/filters/url_filters.rb
+++ b/lib/jekyll/filters/url_filters.rb
@@ -9,8 +9,18 @@ module URLFilters
       #
       # Returns the absolute URL as a String.
       def absolute_url(input)
-        cache = (@context.registers[:cached_absolute_urls] ||= {})
+        return if input.nil?
+
+        cache = if input.is_a?(String)
+                  (@context.registers[:site].filter_cache[:absolute_url] ||= {})
+                else
+                  (@context.registers[:cached_absolute_url] ||= {})
+                end
         cache[input] ||= compute_absolute_url(input)
+
+        # Duplicate cached string so that the cached value is never mutated by
+        # a subsequent filter.
+        cache[input].dup
       end
 
       # Produces a URL relative to the domain root based on site.baseurl
@@ -20,8 +30,18 @@ def absolute_url(input)
       #
       # Returns a URL relative to the domain root as a String.
       def relative_url(input)
-        cache = (@context.registers[:cached_relative_urls] ||= {})
+        return if input.nil?
+
+        cache = if input.is_a?(String)
+                  (@context.registers[:site].filter_cache[:relative_url] ||= {})
+                else
+                  (@context.registers[:cached_relative_url] ||= {})
+                end
         cache[input] ||= compute_relative_url(input)
+
+        # Duplicate cached string so that the cached value is never mutated by
+        # a subsequent filter.
+        cache[input].dup
       end
 
       # Strips trailing `/index.html` from URLs to create pretty permalinks
@@ -38,8 +58,6 @@ def strip_index(input)
       private
 
       def compute_absolute_url(input)
-        return if input.nil?
-
         input = input.url if input.respond_to?(:url)
         return input if Addressable::URI.parse(input.to_s).absolute?
 
@@ -53,8 +71,6 @@ def compute_absolute_url(input)
       end
 
       def compute_relative_url(input)
-        return if input.nil?
-
         input = input.url if input.respond_to?(:url)
         return input if Addressable::URI.parse(input.to_s).absolute?
 
diff --git a/lib/jekyll/site.rb b/lib/jekyll/site.rb
index b8d021013aa..5195a377e1e 100644
--- a/lib/jekyll/site.rb
+++ b/lib/jekyll/site.rb
@@ -10,7 +10,7 @@ class Site
                   :gems, :plugin_manager, :theme
 
     attr_accessor :converters, :generators, :reader
-    attr_reader   :regenerator, :liquid_renderer, :includes_load_paths
+    attr_reader   :regenerator, :liquid_renderer, :includes_load_paths, :filter_cache
 
     # Public: Initialize a new Site.
     #
@@ -23,6 +23,7 @@ def initialize(config)
       self.config = config
 
       @cache_dir       = in_source_dir(config["cache_dir"])
+      @filter_cache    = {}
 
       @reader          = Reader.new(self)
       @regenerator     = Regenerator.new(self)
diff --git a/test/test_filters.rb b/test/test_filters.rb
index 89a586cca4e..6450cae822f 100644
--- a/test/test_filters.rb
+++ b/test/test_filters.rb
@@ -596,6 +596,7 @@ def select; end
         assert_equal "/front_matter.erb", page.url
         url = filter.relative_url(page.url)
         url << "foo"
+        assert_equal "/front_matter.erb", filter.relative_url(page.url)
         assert_equal "/front_matter.erb", page.url
       end