Backport memoize-document-url from #6266 to 3.5-stable [merge conflicts]

lib/jekyll/filters/url_filters.rb

@@ -12,7 +12,7 @@ def absolute_url(input)
         return if input.nil?
         return input if Addressable::URI.parse(input.to_s).absolute?
         site = @context.registers[:site]
-        return relative_url(input) if site.config["url"].nil?
+        return relative_url(input).to_s if site.config["url"].nil?
         Addressable::URI.parse(
           site.config["url"].to_s + relative_url(input)
         ).normalize.to_s

test/test_filters.rb

@@ -13,6 +13,16 @@ def initialize(opts = {})
     end
   end
 
+  class Value
+    def initialize(value)
+      @value = value
+    end
+
+    def to_s
+      @value.respond_to?(:call) ? @value.call : @value.to_s
+    end
+  end
+
   def make_filter_mock(opts = {})
     JekyllFilter.new(site_configuration(opts)).tap do |f|
       tz = f.site.config["timezone"]
@@ -510,6 +520,12 @@ def select; end
         url << "foo"
         assert_equal "/front_matter.erb", page.url
       end
+
+      should "transform the input baseurl to a string" do
+        page_url = "/my-page.html"
+        filter = make_filter_mock({ "baseurl" => Value.new(proc { "/baseurl/" }) })
+        assert_equal "/baseurl#{page_url}", filter.relative_url(page_url)
+      end
     end
 
     context "strip_index filter" do