Rails 6 autoloader: prepare liquid tags code (#8707)

* Move liquid patches to lib/liquid

* Rename classes properly

app/liquid_tags/js_fiddle_tag.rb

@@ -1,4 +1,4 @@
-class JSFiddleTag < LiquidTagBase
+class JsFiddleTag < LiquidTagBase
   PARTIAL = "liquids/jsfiddle".freeze
   OPTION_REGEXP = /\A(js|html|css|result|,)*\z/.freeze
   LINK_REGEXP = /\A(http|https):\/\/(jsfiddle\.net)\/[a-zA-Z0-9\-\/]*\z/.freeze
@@ -51,4 +51,4 @@ class JSFiddleTag < LiquidTagBase
   end
 end
 
-Liquid::Template.register_tag("jsfiddle", JSFiddleTag)
+Liquid::Template.register_tag("jsfiddle", JsFiddleTag)

app/liquid_tags/standard_filters.rb

@@ -1,75 +0,0 @@
-module StandardFilters
-  def append(_input)
-    raise StandardError, "Liquid#append filter is disabled"
-  end
-
-  def concat(_input)
-    raise StandardError, "Liquid#concat filter is disabled"
-  end
-
-  def compact(_input)
-    raise StandardError, "Liquid#compact filter is disabled"
-  end
-
-  def first(_input)
-    raise StandardError, "Liquid#first filter is disabled"
-  end
-
-  def join(_input)
-    raise StandardError, "Liquid#join filter is disabled"
-  end
-
-  def last(_input)
-    raise StandardError, "Liquid#last filter is disabled"
-  end
-
-  def map(_input, _property)
-    raise StandardError, "Liquid#map filter is disabled"
-  end
-
-  def prepend(_input, _string)
-    raise StandardError, "Liquid#prepend filter is disabled"
-  end
-
-  def remove(_input)
-    raise StandardError, "Liquid#remove filter is disabled"
-  end
-
-  def remove_first(_input)
-    raise StandardError, "Liquid#remove_first filter is disabled"
-  end
-
-  def reverse(_input)
-    raise StandardError, "Liquid#reverse filter is disabled"
-  end
-
-  def replace(_input)
-    raise StandardError, "Liquid#replace filter is disabled"
-  end
-
-  def replace_first(_input)
-    raise StandardError, "Liquid#replace_first filter is disabled"
-  end
-
-  def slice(_input)
-    raise StandardError, "Liquid#slice filter is disabled"
-  end
-
-  def split(_input)
-    raise StandardError, "Liquid#split filter is disabled"
-  end
-
-  def truncate(_input)
-    raise StandardError, "Liquid#truncate filter is disabled"
-  end
-
-  def truncatewords(_input)
-    raise StandardError, "Liquid#truncatewords filter is disabled"
-  end
-
-  def uniq(_input, _property)
-    raise StandardError, "Liquid#uniq filter is disabled"
-  end
-end
-
-Liquid::Template.register_filter(StandardFilters)

app/liquid_tags/url_decode_filter.rb

@@ -1,7 +0,0 @@
-module UrlDecodeFilter
-  def url_decode(input)
-    input
-  end
-end
-
-Liquid::Template.register_filter(UrlDecodeFilter)

config/initializers/liquid.rb

@@ -1,3 +1,9 @@
+# TODO: [rhymes] [Rails 6] explicitly requiring dependencies in `classic` mode.
+# Will move over to `zeitwerk` in a future PR
+Dir.glob(Rails.root.join("lib/liquid/*.rb")).sort.each do |filename|
+  require_dependency filename
+end
+
 # Our custom Liquid tags are registered to Liquid::Template at the bottom of
 # each files. Each Liquid tags will need to be loaded/required before the main
 # Liquid gem is evoked, hence the need for the fix below.

lib/liquid/raw.rb

@@ -1,3 +1,6 @@
+# Patches Liquid::Raw to change `FullTokenPossiblyInvalid` regexp
+# see https://github.com/Shopify/liquid/blob/master/lib/liquid/tags/raw.rb
+
 module Liquid
   class Raw < Block
     remove_const(:FullTokenPossiblyInvalid) if defined?(FullTokenPossiblyInvalid)

lib/liquid/variable.rb

@@ -1,3 +1,5 @@
+# Disables regular Liquid::Variables like {{ user.name }}
+# see https://github.com/Shopify/liquid/blob/master/lib/liquid/variable.rb
 module Liquid
   class Variable
     def initialize(_markup, _parse_context)

spec/lib/liquid/raw_spec.rb

@@ -0,0 +1,8 @@
+require "rails_helper"
+
+RSpec.describe Liquid::Raw do
+  it "uses the correct regexp for invalid tokens" do
+    expected_regexp = /\A(.*)#{Liquid::TagStart}\s*(\w+)\s*#{Liquid::TagEnd}\z/om
+    expect(described_class::FullTokenPossiblyInvalid).to eq(expected_regexp)
+  end
+end

spec/lib/liquid/variable_spec.rb

@@ -0,0 +1,7 @@
+require "rails_helper"
+
+RSpec.describe Liquid::Variable do
+  it "does not allow instantiation" do
+    expect { described_class.new("", nil) }.to raise_error(StandardError, /variables are disabled/)
+  end
+end

spec/liquid_tags/js_fiddle_tag_spec.rb

@@ -1,6 +1,6 @@
 require "rails_helper"
 
-RSpec.describe JSFiddleTag, type: :liquid_tag do
+RSpec.describe JsFiddleTag, type: :liquid_tag do
   describe "#link" do
     let(:jsfiddle_link) { "http://jsfiddle.net/link2twenty/v2kx9jcd" }
     let(:jsfiddle_link_with_custom_tabs) { "http://jsfiddle.net/link2twenty/v2kx9jcd result,html,css" }
@@ -12,7 +12,7 @@ RSpec.describe JSFiddleTag, type: :liquid_tag do
     )
 
     def generate_new_liquid(link)
-      Liquid::Template.register_tag("jsfiddle", JSFiddleTag)
+      Liquid::Template.register_tag("jsfiddle", JsFiddleTag)
       Liquid::Template.parse("{% jsfiddle #{link} %}")
     end