Compute document's relative_path faster (#6767)

Merge pull request 6767

benchmark/native-vs-pathutil-relative

@@ -0,0 +1,33 @@
+#!/usr/bin/env ruby
+
+# -------------------------------------------------------------------
+# Benchmarking changes in https://github.com/jekyll/jekyll/pull/6767
+# -------------------------------------------------------------------
+
+require 'benchmark/ips'
+require 'pathutil'
+
+DOC_PATH = File.join(File.expand_path(__dir__), "_puppies", "rover.md")
+COL_PATH = File.join(File.expand_path(__dir__), "_puppies")
+
+
+def pathutil_relative
+  Pathutil.new(DOC_PATH).relative_path_from(COL_PATH).to_s
+end
+
+def native_relative
+  DOC_PATH.sub("#{COL_PATH}/", "")
+end
+
+if pathutil_relative == native_relative
+  Benchmark.ips do |x|
+    x.report("pathutil") { pathutil_relative }
+    x.report("native")   { native_relative }
+    x.compare!
+  end
+else
+  print "PATHUTIL: "
+  puts pathutil_relative
+  print "NATIVE:   "
+  puts native_relative
+end

lib/jekyll/document.rb

@@ -83,8 +83,7 @@ module Jekyll
     # Returns a String path which represents the relative path from the collections_dir
     # to this document.
     def relative_path
-      @relative_path ||=
+      @relative_path ||= path.sub("#{site.collections_path}/", "")
-        Pathutil.new(path).relative_path_from(site.collections_path).to_s
     end
 
     # The output extension of the document.