From ee9777e99b96597fc3403535c592ce818f909277 Mon Sep 17 00:00:00 2001
From: Ashwin Maroli <ashmaroli@gmail.com>
Date: Mon, 4 May 2020 22:21:14 +0530
Subject: [PATCH 01/11] Initialize include-files as Jekyll objects

---
 .rubocop.yml                              |  2 +-
 lib/jekyll.rb                             |  2 +
 lib/jekyll/inclusion.rb                   | 50 +++++++++++++++++++++
 lib/jekyll/reader.rb                      |  1 +
 lib/jekyll/readers/include_file_reader.rb | 54 +++++++++++++++++++++++
 lib/jekyll/site.rb                        |  3 +-
 lib/jekyll/tags/include.rb                | 47 +++++++++++++++++++-
 lib/jekyll/theme.rb                       |  5 +++
 test/test_tags.rb                         | 32 +++++++-------
 9 files changed, 177 insertions(+), 19 deletions(-)
 create mode 100644 lib/jekyll/inclusion.rb
 create mode 100644 lib/jekyll/readers/include_file_reader.rb

diff --git a/.rubocop.yml b/.rubocop.yml
index fb736c5e6c6..e01ea15bc4c 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -52,7 +52,7 @@ Lint/Void:
   Exclude:
     - lib/jekyll/site.rb
 Metrics/AbcSize:
-  Max: 21
+  Max: 24
 Metrics/BlockLength:
   Exclude:
     - test/**/*.rb
diff --git a/lib/jekyll.rb b/lib/jekyll.rb
index 7989dd2e756..0e2f92cdf78 100644
--- a/lib/jekyll.rb
+++ b/lib/jekyll.rb
@@ -54,9 +54,11 @@ module Jekyll
   autoload :FrontmatterDefaults, "jekyll/frontmatter_defaults"
   autoload :Hooks,               "jekyll/hooks"
   autoload :Layout,              "jekyll/layout"
+  autoload :Inclusion,           "jekyll/inclusion"
   autoload :Cache,               "jekyll/cache"
   autoload :CollectionReader,    "jekyll/readers/collection_reader"
   autoload :DataReader,          "jekyll/readers/data_reader"
+  autoload :IncludeFileReader,   "jekyll/readers/include_file_reader"
   autoload :LayoutReader,        "jekyll/readers/layout_reader"
   autoload :PostReader,          "jekyll/readers/post_reader"
   autoload :PageReader,          "jekyll/readers/page_reader"
diff --git a/lib/jekyll/inclusion.rb b/lib/jekyll/inclusion.rb
new file mode 100644
index 00000000000..7d537c8350e
--- /dev/null
+++ b/lib/jekyll/inclusion.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+module Jekyll
+  class Inclusion
+    attr_reader :name, :path, :relative_path
+
+    def initialize(site, base, name)
+      @site = site
+      @name = name
+      @path = PathManager.join(base, name)
+      @relative_path = compute_relative_path
+    end
+
+    def template
+      @template ||= site.liquid_renderer.file(relative_path).parse(content)
+    end
+
+    def content
+      @content ||= File.read(path, **site.file_read_opts)
+    end
+
+    def inspect
+      "#{self.class} #{@relative_path.inspect}"
+    end
+    alias_method :to_s, :inspect
+
+    private
+
+    attr_reader :site
+
+    def dir_path
+      if site.theme && path.start_with?(site.theme.includes_path)
+        PathManager.join site.theme.basename, "_includes"
+      else
+        site.config["includes_dir"]
+      end
+    end
+
+    def compute_relative_path
+      case path
+      when site.theme && %r!#{site.theme.includes_path}/(?<rel_path>.*)!o
+        PathManager.join dir_path, Regexp.last_match[:rel_path]
+      when %r!#{site.in_source_dir(site.config["includes_dir"], "/")}(?<rel_path>.*)!o
+        PathManager.join dir_path, Regexp.last_match[:rel_path]
+      else
+        path.sub(site.in_source_dir("/"), "")
+      end
+    end
+  end
+end
diff --git a/lib/jekyll/reader.rb b/lib/jekyll/reader.rb
index 381d9d3165f..effc849f760 100644
--- a/lib/jekyll/reader.rb
+++ b/lib/jekyll/reader.rb
@@ -18,6 +18,7 @@ def read
       sort_files!
       @site.data = DataReader.new(site).read(site.config["data_dir"])
       CollectionReader.new(site).read
+      IncludeFileReader.new(site).read
       ThemeAssetsReader.new(site).read
     end
 
diff --git a/lib/jekyll/readers/include_file_reader.rb b/lib/jekyll/readers/include_file_reader.rb
new file mode 100644
index 00000000000..20a6384abb9
--- /dev/null
+++ b/lib/jekyll/readers/include_file_reader.rb
@@ -0,0 +1,54 @@
+# frozen_string_literal: true
+
+module Jekyll
+  class IncludeFileReader
+    attr_reader :site
+    def initialize(site)
+      @site = site
+      @inclusions = {}
+    end
+
+    def read
+      site.includes_load_paths.each do |load_path|
+        entries_in(load_path)&.each do |name|
+          @inclusions[name] ||= initialize_validated(load_path, name)
+        end
+      end
+      @inclusions.each_value { |item| item && site.inclusions << item }
+    end
+
+    private
+
+    def initialize_validated(load_path, name)
+      path = PathManager.join(load_path, name)
+      return unless valid_include_path?(load_path, path)
+
+      Inclusion.new(site, load_path, name)
+    end
+
+    def valid_include_path?(directory, path)
+      !outside_scope(directory, path) && !File.directory?(path)
+    end
+
+    def outside_scope(directory, path)
+      site.safe && !realpath_prefixed_with?(directory, path)
+    end
+
+    def realpath_prefixed_with?(dir, path)
+      File.exist?(path) && File.realpath(path).start_with?(dir)
+    rescue StandardError
+      false
+    end
+
+    def entries_in(directory)
+      entries = nil
+      return entries unless File.exist?(directory)
+
+      Dir.chdir(directory) do
+        entries = EntryFilter.new(site).filter(Dir["**/*"])
+      end
+
+      entries
+    end
+  end
+end
diff --git a/lib/jekyll/site.rb b/lib/jekyll/site.rb
index 5195a377e1e..785fc0c81aa 100644
--- a/lib/jekyll/site.rb
+++ b/lib/jekyll/site.rb
@@ -3,7 +3,7 @@
 module Jekyll
   class Site
     attr_reader   :source, :dest, :cache_dir, :config
-    attr_accessor :layouts, :pages, :static_files, :drafts,
+    attr_accessor :layouts, :pages, :static_files, :drafts, :inclusions,
                   :exclude, :include, :lsi, :highlighter, :permalink_style,
                   :time, :future, :unpublished, :safe, :plugins, :limit_posts,
                   :show_drafts, :keep_files, :baseurl, :data, :file_read_opts,
@@ -96,6 +96,7 @@ def reset
                     Time.now
                   end
       self.layouts = {}
+      self.inclusions = []
       self.pages = []
       self.static_files = []
       self.data = {}
diff --git a/lib/jekyll/tags/include.rb b/lib/jekyll/tags/include.rb
index 49ffcb9efbf..b979110cf33 100644
--- a/lib/jekyll/tags/include.rb
+++ b/lib/jekyll/tags/include.rb
@@ -192,6 +192,51 @@ def could_not_locate_message(file, includes_dirs, safe)
       end
     end
 
+    # Do not inherit from this class.
+    # TODO: Merge into the `Jekyll::Tags::IncludeTag` in v5.0
+    class OptimizedIncludeTag < IncludeTag
+      def render(context)
+        @site ||= context.registers[:site]
+
+        file = render_variable(context) || @file
+        validate_file_name(file)
+        inclusion = locate_include(file)
+        return unless inclusion
+
+        add_include_to_dependency(@site, inclusion, context)
+        partial = inclusion.template
+
+        context.stack do
+          context["include"] = parse_params(context) if @params
+          begin
+            partial.render!(context)
+          rescue Liquid::Error => e
+            e.template_name = path
+            e.markup_context = "included " if e.markup_context.nil?
+            raise e
+          end
+        end
+      end
+
+      private
+
+      def locate_include(file)
+        inclusion = @site.inclusions.find { |item| item.name == file }
+        return inclusion if inclusion
+
+        raise IOError, could_not_locate_message(file, @site.includes_load_paths, @site.safe)
+      end
+
+      def add_include_to_dependency(site, inclusion, context)
+        return unless context.registers[:page]&.key?("path")
+
+        site.regenerator.add_dependency(
+          site.in_source_dir(context.registers[:page]["path"]),
+          inclusion.path
+        )
+      end
+    end
+
     class IncludeRelativeTag < IncludeTag
       def tag_includes_dirs(context)
         Array(page_path(context)).freeze
@@ -217,5 +262,5 @@ def page_path(context)
   end
 end
 
-Liquid::Template.register_tag("include", Jekyll::Tags::IncludeTag)
+Liquid::Template.register_tag("include", Jekyll::Tags::OptimizedIncludeTag)
 Liquid::Template.register_tag("include_relative", Jekyll::Tags::IncludeRelativeTag)
diff --git a/lib/jekyll/theme.rb b/lib/jekyll/theme.rb
index 5ef4d044504..3e5172f7ab0 100644
--- a/lib/jekyll/theme.rb
+++ b/lib/jekyll/theme.rb
@@ -21,6 +21,11 @@ def root
         "or includes a symbolic link loop"
     end
 
+    # The name of theme directory
+    def basename
+      @basename ||= File.basename(root)
+    end
+
     def includes_path
       @includes_path ||= path_for "_includes"
     end
diff --git a/test/test_tags.rb b/test/test_tags.rb
index d0eae0d030f..2b973c6e1dc 100644
--- a/test/test_tags.rb
+++ b/test/test_tags.rb
@@ -709,7 +709,7 @@ def highlight_block_with_opts(options_string)
                       "permalink"   => "pretty",
                       "source"      => source_dir,
                       "destination" => dest_dir,
-                      "read_posts"  => true,
+                      "read_all"    => true,
                       "safe"        => true)
         end
         @result ||= ""
@@ -730,7 +730,7 @@ def highlight_block_with_opts(options_string)
                       "permalink"   => "pretty",
                       "source"      => source_dir,
                       "destination" => dest_dir,
-                      "read_posts"  => true,
+                      "read_all"    => true,
                       "safe"        => true)
         end
         assert_match(
@@ -758,7 +758,7 @@ def highlight_block_with_opts(options_string)
                     "permalink"   => "pretty",
                     "source"      => source_dir,
                     "destination" => dest_dir,
-                    "read_posts"  => true)
+                    "read_all"    => true)
       end
 
       should "correctly output include variable" do
@@ -786,7 +786,7 @@ def highlight_block_with_opts(options_string)
                     "permalink"   => "pretty",
                     "source"      => source_dir,
                     "destination" => dest_dir,
-                    "read_posts"  => true)
+                    "read_all"    => true)
       end
 
       should "correctly output include variable" do
@@ -814,7 +814,7 @@ def highlight_block_with_opts(options_string)
                     "permalink"   => "pretty",
                     "source"      => source_dir,
                     "destination" => dest_dir,
-                    "read_posts"  => true)
+                    "read_all"    => true)
       end
 
       should "correctly output include variable" do
@@ -841,7 +841,7 @@ def highlight_block_with_opts(options_string)
                       "permalink"   => "pretty",
                       "source"      => source_dir,
                       "destination" => dest_dir,
-                      "read_posts"  => true)
+                      "read_all"    => true)
         end
 
         content = <<~CONTENT
@@ -857,7 +857,7 @@ def highlight_block_with_opts(options_string)
                       "permalink"   => "pretty",
                       "source"      => source_dir,
                       "destination" => dest_dir,
-                      "read_posts"  => true)
+                      "read_all"    => true)
         end
       end
     end
@@ -875,7 +875,7 @@ def highlight_block_with_opts(options_string)
                     "permalink"   => "pretty",
                     "source"      => source_dir,
                     "destination" => dest_dir,
-                    "read_posts"  => true)
+                    "read_all"    => true)
       end
 
       should "list all parameters" do
@@ -901,7 +901,7 @@ def highlight_block_with_opts(options_string)
                     "permalink"   => "pretty",
                     "source"      => source_dir,
                     "destination" => dest_dir,
-                    "read_posts"  => true)
+                    "read_all"    => true)
       end
 
       should "include file with empty parameters" do
@@ -923,7 +923,7 @@ def highlight_block_with_opts(options_string)
                     "permalink"    => "pretty",
                     "source"       => source_dir,
                     "destination"  => dest_dir,
-                    "read_posts"   => true)
+                    "read_all"     => true)
       end
 
       should "include file from custom directory" do
@@ -944,7 +944,7 @@ def highlight_block_with_opts(options_string)
                     "permalink"   => "pretty",
                     "source"      => source_dir,
                     "destination" => dest_dir,
-                    "read_posts"  => true)
+                    "read_all"    => true)
       end
 
       should "include file with empty parameters within if statement" do
@@ -969,7 +969,7 @@ def highlight_block_with_opts(options_string)
                       "permalink"   => "pretty",
                       "source"      => source_dir,
                       "destination" => dest_dir,
-                      "read_posts"  => true)
+                      "read_all"    => true)
         end
         assert_match(
           "Could not locate the included file 'missing.html' in any of " \
@@ -1063,7 +1063,7 @@ def highlight_block_with_opts(options_string)
                         "permalink"   => "pretty",
                         "source"      => source_dir,
                         "destination" => dest_dir,
-                        "read_posts"  => true)
+                        "read_all"    => true)
           end
           assert_match "Could not locate the included file 'missing.html' in any of " \
                        "[\"#{source_dir}\"].", exception.message
@@ -1087,7 +1087,7 @@ def highlight_block_with_opts(options_string)
                         "permalink"   => "pretty",
                         "source"      => source_dir,
                         "destination" => dest_dir,
-                        "read_posts"  => true)
+                        "read_all"    => true)
           end
           assert_equal(
             "Invalid syntax for include tag. File contains invalid characters or " \
@@ -1115,7 +1115,7 @@ def highlight_block_with_opts(options_string)
                       "permalink"   => "pretty",
                       "source"      => source_dir,
                       "destination" => dest_dir,
-                      "read_posts"  => true,
+                      "read_all"    => true,
                       "safe"        => true)
         end
         @result ||= ""
@@ -1136,7 +1136,7 @@ def highlight_block_with_opts(options_string)
                       "permalink"   => "pretty",
                       "source"      => source_dir,
                       "destination" => dest_dir,
-                      "read_posts"  => true,
+                      "read_all"    => true,
                       "safe"        => true)
         end
         assert_match(

From 797da2e5985c6e133cf004daef6e3265d0e75971 Mon Sep 17 00:00:00 2001
From: Ashwin Maroli <ashmaroli@gmail.com>
Date: Mon, 4 May 2020 23:31:06 +0530
Subject: [PATCH 02/11] Fix failing Cucumber tests

---
 lib/jekyll/inclusion.rb    | 9 ++++++++-
 lib/jekyll/tags/include.rb | 2 +-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/lib/jekyll/inclusion.rb b/lib/jekyll/inclusion.rb
index 7d537c8350e..e89adaaf520 100644
--- a/lib/jekyll/inclusion.rb
+++ b/lib/jekyll/inclusion.rb
@@ -12,7 +12,14 @@ def initialize(site, base, name)
     end
 
     def template
-      @template ||= site.liquid_renderer.file(relative_path).parse(content)
+      @template ||= \
+        begin
+          site.liquid_renderer.file(relative_path).parse(content)
+        rescue Liquid::Error => e
+          e.template_name  = path
+          e.markup_context = "included " if e.markup_context.nil?
+          raise e
+        end
     end
 
     def content
diff --git a/lib/jekyll/tags/include.rb b/lib/jekyll/tags/include.rb
index b979110cf33..de1ae22a50a 100644
--- a/lib/jekyll/tags/include.rb
+++ b/lib/jekyll/tags/include.rb
@@ -211,7 +211,7 @@ def render(context)
           begin
             partial.render!(context)
           rescue Liquid::Error => e
-            e.template_name = path
+            e.template_name  = inclusion.path
             e.markup_context = "included " if e.markup_context.nil?
             raise e
           end

From 9f3b5714baf35ef5d588541b869ba06e0c2ebd20 Mon Sep 17 00:00:00 2001
From: Ashwin Maroli <ashmaroli@gmail.com>
Date: Mon, 4 May 2020 23:31:27 +0530
Subject: [PATCH 03/11] Appease RuboCop

---
 .rubocop.yml            | 2 +-
 lib/jekyll/inclusion.rb | 2 ++
 lib/jekyll/reader.rb    | 3 +++
 lib/jekyll/site.rb      | 2 ++
 4 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/.rubocop.yml b/.rubocop.yml
index e01ea15bc4c..fb736c5e6c6 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -52,7 +52,7 @@ Lint/Void:
   Exclude:
     - lib/jekyll/site.rb
 Metrics/AbcSize:
-  Max: 24
+  Max: 21
 Metrics/BlockLength:
   Exclude:
     - test/**/*.rb
diff --git a/lib/jekyll/inclusion.rb b/lib/jekyll/inclusion.rb
index e89adaaf520..434e395f6f2 100644
--- a/lib/jekyll/inclusion.rb
+++ b/lib/jekyll/inclusion.rb
@@ -43,6 +43,7 @@ def dir_path
       end
     end
 
+    # rubocop:disable Metrics/AbcSize
     def compute_relative_path
       case path
       when site.theme && %r!#{site.theme.includes_path}/(?<rel_path>.*)!o
@@ -53,5 +54,6 @@ def compute_relative_path
         path.sub(site.in_source_dir("/"), "")
       end
     end
+    # rubocop:enable Metrics/AbcSize
   end
 end
diff --git a/lib/jekyll/reader.rb b/lib/jekyll/reader.rb
index effc849f760..641b712af3e 100644
--- a/lib/jekyll/reader.rb
+++ b/lib/jekyll/reader.rb
@@ -8,6 +8,8 @@ def initialize(site)
       @site = site
     end
 
+    # rubocop:disable Metrics/AbcSize
+    #
     # Read Site data from disk and load it into internal data structures.
     #
     # Returns nothing.
@@ -21,6 +23,7 @@ def read
       IncludeFileReader.new(site).read
       ThemeAssetsReader.new(site).read
     end
+    # rubocop:enable Metrics/AbcSize
 
     # Sorts posts, pages, and static files.
     def sort_files!
diff --git a/lib/jekyll/site.rb b/lib/jekyll/site.rb
index 785fc0c81aa..8d71a3ea570 100644
--- a/lib/jekyll/site.rb
+++ b/lib/jekyll/site.rb
@@ -84,6 +84,7 @@ def print_stats
       Jekyll.logger.info @liquid_renderer.stats_table
     end
 
+    # rubocop:disable Metrics/AbcSize
     # rubocop:disable Metrics/MethodLength
     #
     # Reset Site details.
@@ -116,6 +117,7 @@ def reset
       Jekyll::Hooks.trigger :site, :after_reset, self
     end
     # rubocop:enable Metrics/MethodLength
+    # rubocop:enable Metrics/AbcSize
 
     # Load necessary libraries, plugins, converters, and generators.
     #

From c9640f21f102b919c916f7b6a833f24edbe6cd2f Mon Sep 17 00:00:00 2001
From: Ashwin Maroli <ashmaroli@gmail.com>
Date: Wed, 6 May 2020 11:52:57 +0530
Subject: [PATCH 04/11] EntryFilter wasn't involved in the super's render

---
 lib/jekyll/readers/include_file_reader.rb | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/lib/jekyll/readers/include_file_reader.rb b/lib/jekyll/readers/include_file_reader.rb
index 20a6384abb9..db6d9c78f21 100644
--- a/lib/jekyll/readers/include_file_reader.rb
+++ b/lib/jekyll/readers/include_file_reader.rb
@@ -44,10 +44,7 @@ def entries_in(directory)
       entries = nil
       return entries unless File.exist?(directory)
 
-      Dir.chdir(directory) do
-        entries = EntryFilter.new(site).filter(Dir["**/*"])
-      end
-
+      Dir.chdir(directory) { entries = Dir["**/*"] }
       entries
     end
   end

From 7e62659574515ba0fff207e17af6f697ce2a0934 Mon Sep 17 00:00:00 2001
From: Ashwin Maroli <ashmaroli@gmail.com>
Date: Wed, 6 May 2020 11:57:03 +0530
Subject: [PATCH 05/11] Combine duplicated code

---
 lib/jekyll/inclusion.rb    | 16 +++++++---------
 lib/jekyll/tags/include.rb |  8 +-------
 2 files changed, 8 insertions(+), 16 deletions(-)

diff --git a/lib/jekyll/inclusion.rb b/lib/jekyll/inclusion.rb
index 434e395f6f2..d834f9277e5 100644
--- a/lib/jekyll/inclusion.rb
+++ b/lib/jekyll/inclusion.rb
@@ -11,15 +11,13 @@ def initialize(site, base, name)
       @relative_path = compute_relative_path
     end
 
-    def template
-      @template ||= \
-        begin
-          site.liquid_renderer.file(relative_path).parse(content)
-        rescue Liquid::Error => e
-          e.template_name  = path
-          e.markup_context = "included " if e.markup_context.nil?
-          raise e
-        end
+    def render(context)
+      @template ||= site.liquid_renderer.file(relative_path).parse(content)
+      @template.render!(context)
+    rescue Liquid::Error => e
+      e.template_name  = path
+      e.markup_context = "included " if e.markup_context.nil?
+      raise e
     end
 
     def content
diff --git a/lib/jekyll/tags/include.rb b/lib/jekyll/tags/include.rb
index de1ae22a50a..4347dbe57dc 100644
--- a/lib/jekyll/tags/include.rb
+++ b/lib/jekyll/tags/include.rb
@@ -208,13 +208,7 @@ def render(context)
 
         context.stack do
           context["include"] = parse_params(context) if @params
-          begin
-            partial.render!(context)
-          rescue Liquid::Error => e
-            e.template_name  = inclusion.path
-            e.markup_context = "included " if e.markup_context.nil?
-            raise e
-          end
+          inclusion.render(context)
         end
       end
 

From 0b93dbdf9138f795fbb02f4ca2ef7fb570316ab8 Mon Sep 17 00:00:00 2001
From: Ashwin Maroli <ashmaroli@gmail.com>
Date: Wed, 6 May 2020 11:59:55 +0530
Subject: [PATCH 06/11] Refactor to reduce computations

---
 lib/jekyll/inclusion.rb                   |  9 ++++++---
 lib/jekyll/readers/include_file_reader.rb |  5 ++---
 lib/jekyll/site.rb                        |  2 +-
 lib/jekyll/tags/include.rb                | 20 +++++++-------------
 4 files changed, 16 insertions(+), 20 deletions(-)

diff --git a/lib/jekyll/inclusion.rb b/lib/jekyll/inclusion.rb
index d834f9277e5..67877571c16 100644
--- a/lib/jekyll/inclusion.rb
+++ b/lib/jekyll/inclusion.rb
@@ -2,13 +2,16 @@
 
 module Jekyll
   class Inclusion
-    attr_reader :name, :path, :relative_path
+    attr_reader :name, :path
 
     def initialize(site, base, name)
       @site = site
       @name = name
       @path = PathManager.join(base, name)
-      @relative_path = compute_relative_path
+    end
+
+    def relative_path
+      @relative_path ||= compute_relative_path
     end
 
     def render(context)
@@ -25,7 +28,7 @@ def content
     end
 
     def inspect
-      "#{self.class} #{@relative_path.inspect}"
+      "#{self.class} #{relative_path.inspect}"
     end
     alias_method :to_s, :inspect
 
diff --git a/lib/jekyll/readers/include_file_reader.rb b/lib/jekyll/readers/include_file_reader.rb
index db6d9c78f21..98ff7b4e421 100644
--- a/lib/jekyll/readers/include_file_reader.rb
+++ b/lib/jekyll/readers/include_file_reader.rb
@@ -5,16 +5,15 @@ class IncludeFileReader
     attr_reader :site
     def initialize(site)
       @site = site
-      @inclusions = {}
     end
 
     def read
       site.includes_load_paths.each do |load_path|
         entries_in(load_path)&.each do |name|
-          @inclusions[name] ||= initialize_validated(load_path, name)
+          inclusion = initialize_validated(load_path, name)
+          inclusion && site.inclusions[name] ||= inclusion
         end
       end
-      @inclusions.each_value { |item| item && site.inclusions << item }
     end
 
     private
diff --git a/lib/jekyll/site.rb b/lib/jekyll/site.rb
index 8d71a3ea570..26495ad3095 100644
--- a/lib/jekyll/site.rb
+++ b/lib/jekyll/site.rb
@@ -97,7 +97,7 @@ def reset
                     Time.now
                   end
       self.layouts = {}
-      self.inclusions = []
+      self.inclusions = {}
       self.pages = []
       self.static_files = []
       self.data = {}
diff --git a/lib/jekyll/tags/include.rb b/lib/jekyll/tags/include.rb
index 4347dbe57dc..9b75ae82103 100644
--- a/lib/jekyll/tags/include.rb
+++ b/lib/jekyll/tags/include.rb
@@ -200,11 +200,8 @@ def render(context)
 
         file = render_variable(context) || @file
         validate_file_name(file)
-        inclusion = locate_include(file)
-        return unless inclusion
-
-        add_include_to_dependency(@site, inclusion, context)
-        partial = inclusion.template
+        inclusion = @site.inclusions[file] || raise(IOError, could_not_locate_message(file))
+        add_include_to_dependency(inclusion, context) if @site.incremental?
 
         context.stack do
           context["include"] = parse_params(context) if @params
@@ -214,18 +211,15 @@ def render(context)
 
       private
 
-      def locate_include(file)
-        inclusion = @site.inclusions.find { |item| item.name == file }
-        return inclusion if inclusion
-
-        raise IOError, could_not_locate_message(file, @site.includes_load_paths, @site.safe)
+      def could_not_locate_message(file)
+        super(file, @site.includes_load_paths, @site.safe)
       end
 
-      def add_include_to_dependency(site, inclusion, context)
+      def add_include_to_dependency(inclusion, context)
         return unless context.registers[:page]&.key?("path")
 
-        site.regenerator.add_dependency(
-          site.in_source_dir(context.registers[:page]["path"]),
+        @site.regenerator.add_dependency(
+          @site.in_source_dir(context.registers[:page]["path"]),
           inclusion.path
         )
       end

From 8e1d624013e3f4355bbe06c33e9012a74f7bbb2c Mon Sep 17 00:00:00 2001
From: Ashwin Maroli <ashmaroli@gmail.com>
Date: Wed, 6 May 2020 17:16:47 +0530
Subject: [PATCH 07/11] Reduce duplicate string count

---
 lib/jekyll/tags/include.rb | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/jekyll/tags/include.rb b/lib/jekyll/tags/include.rb
index 9b75ae82103..d381a10f7bb 100644
--- a/lib/jekyll/tags/include.rb
+++ b/lib/jekyll/tags/include.rb
@@ -18,12 +18,13 @@ class IncludeTag < Liquid::Tag
 
       def initialize(tag_name, markup, tokens)
         super
-        matched = markup.strip.match(VARIABLE_SYNTAX)
+        markup  = markup.strip
+        matched = markup.match(VARIABLE_SYNTAX)
         if matched
           @file = matched["variable"].strip
           @params = matched["params"].strip
         else
-          @file, @params = markup.strip.split(%r!\s+!, 2)
+          @file, @params = markup.split(%r!\s+!, 2)
         end
         validate_params if @params
         @tag_name = tag_name

From 1129e5b7e22d56b2daacdd2cd963f21161196920 Mon Sep 17 00:00:00 2001
From: Ashwin Maroli <ashmaroli@gmail.com>
Date: Wed, 6 May 2020 23:20:21 +0530
Subject: [PATCH 08/11] Fold IncludeFileReader into OptimizedIncludeTag

---
 lib/jekyll.rb                             |  1 -
 lib/jekyll/reader.rb                      |  4 --
 lib/jekyll/readers/include_file_reader.rb | 50 -----------------------
 lib/jekyll/tags/include.rb                | 27 ++++++++++--
 test/test_tags.rb                         | 32 +++++++--------
 5 files changed, 40 insertions(+), 74 deletions(-)
 delete mode 100644 lib/jekyll/readers/include_file_reader.rb

diff --git a/lib/jekyll.rb b/lib/jekyll.rb
index 0e2f92cdf78..9add96121b9 100644
--- a/lib/jekyll.rb
+++ b/lib/jekyll.rb
@@ -58,7 +58,6 @@ module Jekyll
   autoload :Cache,               "jekyll/cache"
   autoload :CollectionReader,    "jekyll/readers/collection_reader"
   autoload :DataReader,          "jekyll/readers/data_reader"
-  autoload :IncludeFileReader,   "jekyll/readers/include_file_reader"
   autoload :LayoutReader,        "jekyll/readers/layout_reader"
   autoload :PostReader,          "jekyll/readers/post_reader"
   autoload :PageReader,          "jekyll/readers/page_reader"
diff --git a/lib/jekyll/reader.rb b/lib/jekyll/reader.rb
index 641b712af3e..381d9d3165f 100644
--- a/lib/jekyll/reader.rb
+++ b/lib/jekyll/reader.rb
@@ -8,8 +8,6 @@ def initialize(site)
       @site = site
     end
 
-    # rubocop:disable Metrics/AbcSize
-    #
     # Read Site data from disk and load it into internal data structures.
     #
     # Returns nothing.
@@ -20,10 +18,8 @@ def read
       sort_files!
       @site.data = DataReader.new(site).read(site.config["data_dir"])
       CollectionReader.new(site).read
-      IncludeFileReader.new(site).read
       ThemeAssetsReader.new(site).read
     end
-    # rubocop:enable Metrics/AbcSize
 
     # Sorts posts, pages, and static files.
     def sort_files!
diff --git a/lib/jekyll/readers/include_file_reader.rb b/lib/jekyll/readers/include_file_reader.rb
deleted file mode 100644
index 98ff7b4e421..00000000000
--- a/lib/jekyll/readers/include_file_reader.rb
+++ /dev/null
@@ -1,50 +0,0 @@
-# frozen_string_literal: true
-
-module Jekyll
-  class IncludeFileReader
-    attr_reader :site
-    def initialize(site)
-      @site = site
-    end
-
-    def read
-      site.includes_load_paths.each do |load_path|
-        entries_in(load_path)&.each do |name|
-          inclusion = initialize_validated(load_path, name)
-          inclusion && site.inclusions[name] ||= inclusion
-        end
-      end
-    end
-
-    private
-
-    def initialize_validated(load_path, name)
-      path = PathManager.join(load_path, name)
-      return unless valid_include_path?(load_path, path)
-
-      Inclusion.new(site, load_path, name)
-    end
-
-    def valid_include_path?(directory, path)
-      !outside_scope(directory, path) && !File.directory?(path)
-    end
-
-    def outside_scope(directory, path)
-      site.safe && !realpath_prefixed_with?(directory, path)
-    end
-
-    def realpath_prefixed_with?(dir, path)
-      File.exist?(path) && File.realpath(path).start_with?(dir)
-    rescue StandardError
-      false
-    end
-
-    def entries_in(directory)
-      entries = nil
-      return entries unless File.exist?(directory)
-
-      Dir.chdir(directory) { entries = Dir["**/*"] }
-      entries
-    end
-  end
-end
diff --git a/lib/jekyll/tags/include.rb b/lib/jekyll/tags/include.rb
index d381a10f7bb..8e612032d96 100644
--- a/lib/jekyll/tags/include.rb
+++ b/lib/jekyll/tags/include.rb
@@ -201,7 +201,10 @@ def render(context)
 
         file = render_variable(context) || @file
         validate_file_name(file)
-        inclusion = @site.inclusions[file] || raise(IOError, could_not_locate_message(file))
+
+        @site.inclusions[file] ||= locate_include_file(file)
+        inclusion = @site.inclusions[file]
+
         add_include_to_dependency(inclusion, context) if @site.incremental?
 
         context.stack do
@@ -212,8 +215,26 @@ def render(context)
 
       private
 
-      def could_not_locate_message(file)
-        super(file, @site.includes_load_paths, @site.safe)
+      def locate_include_file(file)
+        @site.includes_load_paths.each do |dir|
+          path = PathManager.join(dir, file)
+          return Inclusion.new(@site, dir, file) if valid_include_file?(path, dir)
+        end
+        raise IOError, could_not_locate_message(file, @site.includes_load_paths, @site.safe)
+      end
+
+      def valid_include_file?(path, dir)
+        File.exist?(path) && !File.directory?(path) && !outside_scope?(path, dir)
+      end
+
+      def outside_scope?(path, dir)
+        @site.safe && !realpath_prefixed_with?(path, dir)
+      end
+
+      def realpath_prefixed_with?(path, dir)
+        File.realpath(path).start_with?(dir)
+      rescue StandardError
+        false
       end
 
       def add_include_to_dependency(inclusion, context)
diff --git a/test/test_tags.rb b/test/test_tags.rb
index 2b973c6e1dc..d0eae0d030f 100644
--- a/test/test_tags.rb
+++ b/test/test_tags.rb
@@ -709,7 +709,7 @@ def highlight_block_with_opts(options_string)
                       "permalink"   => "pretty",
                       "source"      => source_dir,
                       "destination" => dest_dir,
-                      "read_all"    => true,
+                      "read_posts"  => true,
                       "safe"        => true)
         end
         @result ||= ""
@@ -730,7 +730,7 @@ def highlight_block_with_opts(options_string)
                       "permalink"   => "pretty",
                       "source"      => source_dir,
                       "destination" => dest_dir,
-                      "read_all"    => true,
+                      "read_posts"  => true,
                       "safe"        => true)
         end
         assert_match(
@@ -758,7 +758,7 @@ def highlight_block_with_opts(options_string)
                     "permalink"   => "pretty",
                     "source"      => source_dir,
                     "destination" => dest_dir,
-                    "read_all"    => true)
+                    "read_posts"  => true)
       end
 
       should "correctly output include variable" do
@@ -786,7 +786,7 @@ def highlight_block_with_opts(options_string)
                     "permalink"   => "pretty",
                     "source"      => source_dir,
                     "destination" => dest_dir,
-                    "read_all"    => true)
+                    "read_posts"  => true)
       end
 
       should "correctly output include variable" do
@@ -814,7 +814,7 @@ def highlight_block_with_opts(options_string)
                     "permalink"   => "pretty",
                     "source"      => source_dir,
                     "destination" => dest_dir,
-                    "read_all"    => true)
+                    "read_posts"  => true)
       end
 
       should "correctly output include variable" do
@@ -841,7 +841,7 @@ def highlight_block_with_opts(options_string)
                       "permalink"   => "pretty",
                       "source"      => source_dir,
                       "destination" => dest_dir,
-                      "read_all"    => true)
+                      "read_posts"  => true)
         end
 
         content = <<~CONTENT
@@ -857,7 +857,7 @@ def highlight_block_with_opts(options_string)
                       "permalink"   => "pretty",
                       "source"      => source_dir,
                       "destination" => dest_dir,
-                      "read_all"    => true)
+                      "read_posts"  => true)
         end
       end
     end
@@ -875,7 +875,7 @@ def highlight_block_with_opts(options_string)
                     "permalink"   => "pretty",
                     "source"      => source_dir,
                     "destination" => dest_dir,
-                    "read_all"    => true)
+                    "read_posts"  => true)
       end
 
       should "list all parameters" do
@@ -901,7 +901,7 @@ def highlight_block_with_opts(options_string)
                     "permalink"   => "pretty",
                     "source"      => source_dir,
                     "destination" => dest_dir,
-                    "read_all"    => true)
+                    "read_posts"  => true)
       end
 
       should "include file with empty parameters" do
@@ -923,7 +923,7 @@ def highlight_block_with_opts(options_string)
                     "permalink"    => "pretty",
                     "source"       => source_dir,
                     "destination"  => dest_dir,
-                    "read_all"     => true)
+                    "read_posts"   => true)
       end
 
       should "include file from custom directory" do
@@ -944,7 +944,7 @@ def highlight_block_with_opts(options_string)
                     "permalink"   => "pretty",
                     "source"      => source_dir,
                     "destination" => dest_dir,
-                    "read_all"    => true)
+                    "read_posts"  => true)
       end
 
       should "include file with empty parameters within if statement" do
@@ -969,7 +969,7 @@ def highlight_block_with_opts(options_string)
                       "permalink"   => "pretty",
                       "source"      => source_dir,
                       "destination" => dest_dir,
-                      "read_all"    => true)
+                      "read_posts"  => true)
         end
         assert_match(
           "Could not locate the included file 'missing.html' in any of " \
@@ -1063,7 +1063,7 @@ def highlight_block_with_opts(options_string)
                         "permalink"   => "pretty",
                         "source"      => source_dir,
                         "destination" => dest_dir,
-                        "read_all"    => true)
+                        "read_posts"  => true)
           end
           assert_match "Could not locate the included file 'missing.html' in any of " \
                        "[\"#{source_dir}\"].", exception.message
@@ -1087,7 +1087,7 @@ def highlight_block_with_opts(options_string)
                         "permalink"   => "pretty",
                         "source"      => source_dir,
                         "destination" => dest_dir,
-                        "read_all"    => true)
+                        "read_posts"  => true)
           end
           assert_equal(
             "Invalid syntax for include tag. File contains invalid characters or " \
@@ -1115,7 +1115,7 @@ def highlight_block_with_opts(options_string)
                       "permalink"   => "pretty",
                       "source"      => source_dir,
                       "destination" => dest_dir,
-                      "read_all"    => true,
+                      "read_posts"  => true,
                       "safe"        => true)
         end
         @result ||= ""
@@ -1136,7 +1136,7 @@ def highlight_block_with_opts(options_string)
                       "permalink"   => "pretty",
                       "source"      => source_dir,
                       "destination" => dest_dir,
-                      "read_all"    => true,
+                      "read_posts"  => true,
                       "safe"        => true)
         end
         assert_match(

From 5b81aa945351b99c5f034e1c3b5eaa7e775d41db Mon Sep 17 00:00:00 2001
From: Ashwin Maroli <ashmaroli@gmail.com>
Date: Thu, 14 May 2020 15:12:19 +0530
Subject: [PATCH 09/11] Make `Inclusion#relative_path` a private method

---
 lib/jekyll/inclusion.rb | 31 +++++++++++--------------------
 1 file changed, 11 insertions(+), 20 deletions(-)

diff --git a/lib/jekyll/inclusion.rb b/lib/jekyll/inclusion.rb
index 67877571c16..1d813fd6981 100644
--- a/lib/jekyll/inclusion.rb
+++ b/lib/jekyll/inclusion.rb
@@ -10,10 +10,6 @@ def initialize(site, base, name)
       @path = PathManager.join(base, name)
     end
 
-    def relative_path
-      @relative_path ||= compute_relative_path
-    end
-
     def render(context)
       @template ||= site.liquid_renderer.file(relative_path).parse(content)
       @template.render!(context)
@@ -36,23 +32,18 @@ def inspect
 
     attr_reader :site
 
-    def dir_path
-      if site.theme && path.start_with?(site.theme.includes_path)
-        PathManager.join site.theme.basename, "_includes"
-      else
-        site.config["includes_dir"]
-      end
-    end
-
     # rubocop:disable Metrics/AbcSize
-    def compute_relative_path
-      case path
-      when site.theme && %r!#{site.theme.includes_path}/(?<rel_path>.*)!o
-        PathManager.join dir_path, Regexp.last_match[:rel_path]
-      when %r!#{site.in_source_dir(site.config["includes_dir"], "/")}(?<rel_path>.*)!o
-        PathManager.join dir_path, Regexp.last_match[:rel_path]
-      else
-        path.sub(site.in_source_dir("/"), "")
+    def relative_path
+      @relative_path ||= begin
+        case path
+        when site.theme && %r!#{site.theme.includes_path}/(?<rel_path>.*)!o
+          dir_path = PathManager.join(site.theme.basename, "_includes")
+          PathManager.join(dir_path, Regexp.last_match[:rel_path])
+        when %r!#{site.in_source_dir(site.config["includes_dir"], "/")}(?<rel_path>.*)!o
+          PathManager.join(site.config["includes_dir"], Regexp.last_match[:rel_path])
+        else
+          path.sub(site.in_source_dir("/"), "")
+        end
       end
     end
     # rubocop:enable Metrics/AbcSize

From ba36d074dc31cf9b142baff0e8235fae5a683828 Mon Sep 17 00:00:00 2001
From: Ashwin Maroli <ashmaroli@gmail.com>
Date: Thu, 14 May 2020 15:39:07 +0530
Subject: [PATCH 10/11] Remove relative_path attribute from Inclusion objs

---
 lib/jekyll/inclusion.rb | 27 ++++-----------------------
 1 file changed, 4 insertions(+), 23 deletions(-)

diff --git a/lib/jekyll/inclusion.rb b/lib/jekyll/inclusion.rb
index 1d813fd6981..179ddb045cb 100644
--- a/lib/jekyll/inclusion.rb
+++ b/lib/jekyll/inclusion.rb
@@ -2,7 +2,8 @@
 
 module Jekyll
   class Inclusion
-    attr_reader :name, :path
+    attr_reader :site, :name, :path
+    private :site
 
     def initialize(site, base, name)
       @site = site
@@ -11,7 +12,7 @@ def initialize(site, base, name)
     end
 
     def render(context)
-      @template ||= site.liquid_renderer.file(relative_path).parse(content)
+      @template ||= site.liquid_renderer.file(path).parse(content)
       @template.render!(context)
     rescue Liquid::Error => e
       e.template_name  = path
@@ -24,28 +25,8 @@ def content
     end
 
     def inspect
-      "#{self.class} #{relative_path.inspect}"
+      "#{self.class} #{path.inspect}"
     end
     alias_method :to_s, :inspect
-
-    private
-
-    attr_reader :site
-
-    # rubocop:disable Metrics/AbcSize
-    def relative_path
-      @relative_path ||= begin
-        case path
-        when site.theme && %r!#{site.theme.includes_path}/(?<rel_path>.*)!o
-          dir_path = PathManager.join(site.theme.basename, "_includes")
-          PathManager.join(dir_path, Regexp.last_match[:rel_path])
-        when %r!#{site.in_source_dir(site.config["includes_dir"], "/")}(?<rel_path>.*)!o
-          PathManager.join(site.config["includes_dir"], Regexp.last_match[:rel_path])
-        else
-          path.sub(site.in_source_dir("/"), "")
-        end
-      end
-    end
-    # rubocop:enable Metrics/AbcSize
   end
 end

From 78798b0c60e2912ea16712e8b067526d160697af Mon Sep 17 00:00:00 2001
From: Ashwin Maroli <ashmaroli@gmail.com>
Date: Thu, 14 May 2020 15:42:03 +0530
Subject: [PATCH 11/11] File.file? checks if path exists and is a file

---
 lib/jekyll/tags/include.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/jekyll/tags/include.rb b/lib/jekyll/tags/include.rb
index 8e612032d96..cc6b145102f 100644
--- a/lib/jekyll/tags/include.rb
+++ b/lib/jekyll/tags/include.rb
@@ -224,7 +224,7 @@ def locate_include_file(file)
       end
 
       def valid_include_file?(path, dir)
-        File.exist?(path) && !File.directory?(path) && !outside_scope?(path, dir)
+        File.file?(path) && !outside_scope?(path, dir)
       end
 
       def outside_scope?(path, dir)