Merge branch 'master' into feature/reselect-method

28 files changed, 249 insertions, 100 deletions

diff --git a/actionview/lib/action_view/buffers.rb b/actionview/lib/action_view/buffers.rb
index 2a378fdc3c..18eaee5d79 100644
--- a/actionview/lib/action_view/buffers.rb
+++ b/actionview/lib/action_view/buffers.rb
@@ -3,6 +3,21 @@
 require "active_support/core_ext/string/output_safety"
 
 module ActionView
+  # Used as a buffer for views
+  #
+  # The main difference between this and ActiveSupport::SafeBuffer
+  # is for the methods `<<` and `safe_expr_append=` the inputs are
+  # checked for nil before they are assigned and `to_s` is called on
+  # the input. For example:
+  #
+  #   obuf = ActionView::OutputBuffer.new "hello"
+  #   obuf << 5
+  #   puts obuf # => "hello5"
+  #
+  #   sbuf = ActiveSupport::SafeBuffer.new "hello"
+  #   sbuf << 5
+  #   puts sbuf # => "hello\u0005"
+  #
   class OutputBuffer < ActiveSupport::SafeBuffer #:nodoc:
     def initialize(*)
       super
diff --git a/actionview/lib/action_view/digestor.rb b/actionview/lib/action_view/digestor.rb
index 39cdecb9e4..6d2e471a44 100644
--- a/actionview/lib/action_view/digestor.rb
+++ b/actionview/lib/action_view/digestor.rb
@@ -18,9 +18,12 @@ module ActionView
       # * <tt>name</tt>   - Template name
       # * <tt>finder</tt>  - An instance of <tt>ActionView::LookupContext</tt>
       # * <tt>dependencies</tt>  - An array of dependent views
-      def digest(name:, finder:, dependencies: [])
-        dependencies ||= []
-        cache_key = [ name, finder.rendered_format, dependencies ].flatten.compact.join(".")
+      def digest(name:, finder:, dependencies: nil)
+        if dependencies.nil? || dependencies.empty?
+          cache_key = "#{name}.#{finder.rendered_format}"
+        else
+          cache_key = [ name, finder.rendered_format, dependencies ].flatten.compact.join(".")
+        end
 
         # this is a correctly done double-checked locking idiom
         # (Concurrent::Map's lookups have volatile semantics)
@@ -30,7 +33,7 @@ module ActionView
             root = tree(name, finder, partial)
             dependencies.each do |injected_dep|
               root.children << Injected.new(injected_dep, nil, nil)
-            end
+            end if dependencies
             finder.digest_cache[cache_key] = root.digest(finder)
           end
         end
diff --git a/actionview/lib/action_view/helpers/asset_tag_helper.rb b/actionview/lib/action_view/helpers/asset_tag_helper.rb
index 14bd8ffa84..3d7c8dae75 100644
--- a/actionview/lib/action_view/helpers/asset_tag_helper.rb
+++ b/actionview/lib/action_view/helpers/asset_tag_helper.rb
@@ -55,7 +55,7 @@ module ActionView
       #   that path.
       # * <tt>:skip_pipeline</tt>  - This option is used to bypass the asset pipeline
       #   when it is set to true.
-      # * <tt>:nonce<tt>  - When set to true, adds an automatic nonce value if
+      # * <tt>:nonce</tt>  - When set to true, adds an automatic nonce value if
       #   you have Content Security Policy enabled.
       #
       # ==== Examples
@@ -98,7 +98,7 @@ module ActionView
           if tag_options["nonce"] == true
             tag_options["nonce"] = content_security_policy_nonce
           end
-          content_tag("script".freeze, "", tag_options)
+          content_tag("script", "", tag_options)
         }.join("\n").html_safe
 
         request.send_early_hints("Link" => early_hints_links.join("\n")) if respond_to?(:request) && request
@@ -375,7 +375,7 @@ module ActionView
       def image_alt(src)
         ActiveSupport::Deprecation.warn("image_alt is deprecated and will be removed from Rails 6.0. You must explicitly set alt text on images.")
 
-        File.basename(src, ".*".freeze).sub(/-[[:xdigit:]]{32,64}\z/, "".freeze).tr("-_".freeze, " ".freeze).capitalize
+        File.basename(src, ".*").sub(/-[[:xdigit:]]{32,64}\z/, "").tr("-_", " ").capitalize
       end
 
       # Returns an HTML video tag for the +sources+. If +sources+ is a string,
diff --git a/actionview/lib/action_view/helpers/asset_url_helper.rb b/actionview/lib/action_view/helpers/asset_url_helper.rb
index 1808765666..cc62783d60 100644
--- a/actionview/lib/action_view/helpers/asset_url_helper.rb
+++ b/actionview/lib/action_view/helpers/asset_url_helper.rb
@@ -188,7 +188,7 @@ module ActionView
         return "" if source.blank?
         return source if URI_REGEXP.match?(source)
 
-        tail, source = source[/([\?#].+)$/], source.sub(/([\?#].+)$/, "".freeze)
+        tail, source = source[/([\?#].+)$/], source.sub(/([\?#].+)$/, "")
 
         if extname = compute_asset_extname(source, options)
           source = "#{source}#{extname}"
diff --git a/actionview/lib/action_view/helpers/cache_helper.rb b/actionview/lib/action_view/helpers/cache_helper.rb
index 15d187a9ec..b1a14250c3 100644
--- a/actionview/lib/action_view/helpers/cache_helper.rb
+++ b/actionview/lib/action_view/helpers/cache_helper.rb
@@ -208,27 +208,35 @@ module ActionView
       #
       # The digest will be generated using +virtual_path:+ if it is provided.
       #
-      def cache_fragment_name(name = {}, skip_digest: nil, virtual_path: nil)
+      def cache_fragment_name(name = {}, skip_digest: nil, virtual_path: nil, digest_path: nil)
         if skip_digest
           name
         else
-          fragment_name_with_digest(name, virtual_path)
+          fragment_name_with_digest(name, virtual_path, digest_path)
+        end
+      end
+
+      def digest_path_from_virtual(virtual_path) # :nodoc:
+        digest = Digestor.digest(name: virtual_path, finder: lookup_context, dependencies: view_cache_dependencies)
+
+        if digest.present?
+          "#{virtual_path}:#{digest}"
+        else
+          virtual_path
         end
       end
 
     private
 
-      def fragment_name_with_digest(name, virtual_path)
+      def fragment_name_with_digest(name, virtual_path, digest_path)
         virtual_path ||= @virtual_path
 
-        if virtual_path
+        if virtual_path || digest_path
           name = controller.url_for(name).split("://").last if name.is_a?(Hash)
 
-          if digest = Digestor.digest(name: virtual_path, finder: lookup_context, dependencies: view_cache_dependencies).presence
-            [ "#{virtual_path}:#{digest}", name ]
-          else
-            [ virtual_path, name ]
-          end
+          digest_path ||= digest_path_from_virtual(virtual_path)
+
+          [ digest_path, name ]
         else
           name
         end
diff --git a/actionview/lib/action_view/helpers/capture_helper.rb b/actionview/lib/action_view/helpers/capture_helper.rb
index 92f7ddb70d..c87c212cc7 100644
--- a/actionview/lib/action_view/helpers/capture_helper.rb
+++ b/actionview/lib/action_view/helpers/capture_helper.rb
@@ -36,6 +36,10 @@ module ActionView
       #   </body>
       #   </html>
       #
+      # The return of capture is the string generated by the block. For Example:
+      #
+      #   @greeting # => "Welcome to my shiny new web page! The date and time is 2018-09-06 11:09:16 -0500"
+      #
       def capture(*args)
         value = nil
         buffer = with_output_buffer { value = yield(*args) }
diff --git a/actionview/lib/action_view/helpers/date_helper.rb b/actionview/lib/action_view/helpers/date_helper.rb
index 4de4fafde0..9d5e5eaba3 100644
--- a/actionview/lib/action_view/helpers/date_helper.rb
+++ b/actionview/lib/action_view/helpers/date_helper.rb
@@ -684,7 +684,7 @@ module ActionView
         format   = options.delete(:format) || :long
         content  = args.first || I18n.l(date_or_time, format: format)
 
-        content_tag("time".freeze, content, options.reverse_merge(datetime: date_or_time.iso8601), &block)
+        content_tag("time", content, options.reverse_merge(datetime: date_or_time.iso8601), &block)
       end
 
       private
@@ -703,7 +703,7 @@ module ActionView
     class DateTimeSelector #:nodoc:
       include ActionView::Helpers::TagHelper
 
-      DEFAULT_PREFIX = "date".freeze
+      DEFAULT_PREFIX = "date"
       POSITION = {
         year: 1, month: 2, day: 3, hour: 4, minute: 5, second: 6
       }.freeze
@@ -824,7 +824,7 @@ module ActionView
           1.upto(12) do |month_number|
             options = { value: month_number }
             options[:selected] = "selected" if month == month_number
-            month_options << content_tag("option".freeze, month_name(month_number), options) + "\n"
+            month_options << content_tag("option", month_name(month_number), options) + "\n"
           end
           build_select(:month, month_options.join)
         end
@@ -1006,7 +1006,7 @@ module ActionView
             tag_options[:selected] = "selected" if selected == i
             text = options[:use_two_digit_numbers] ? sprintf("%02d", i) : value
             text = options[:ampm] ? AMPM_TRANSLATION[i] : text
-            select_options << content_tag("option".freeze, text, tag_options)
+            select_options << content_tag("option", text, tag_options)
           end
 
           (select_options.join("\n") + "\n").html_safe
@@ -1034,7 +1034,7 @@ module ActionView
             tag_options = { value: value }
             tag_options[:selected] = "selected" if selected == value
             text = year_name(value)
-            select_options << content_tag("option".freeze, text, tag_options)
+            select_options << content_tag("option", text, tag_options)
           end
 
           (select_options.join("\n") + "\n").html_safe
@@ -1053,12 +1053,12 @@ module ActionView
           select_options[:disabled] = "disabled" if @options[:disabled]
           select_options[:class] = css_class_attribute(type, select_options[:class], @options[:with_css_classes]) if @options[:with_css_classes]
 
-          select_html = "\n".dup
-          select_html << content_tag("option".freeze, "", value: "") + "\n" if @options[:include_blank]
+          select_html = +"\n"
+          select_html << content_tag("option", "", value: "") + "\n" if @options[:include_blank]
           select_html << prompt_option_tag(type, @options[:prompt]) + "\n" if @options[:prompt]
           select_html << select_options_as_html
 
-          (content_tag("select".freeze, select_html.html_safe, select_options) + "\n").html_safe
+          (content_tag("select", select_html.html_safe, select_options) + "\n").html_safe
         end
 
         # Builds the css class value for the select element
@@ -1091,7 +1091,7 @@ module ActionView
               I18n.translate(:"datetime.prompts.#{type}", locale: @options[:locale])
             end
 
-          prompt ? content_tag("option".freeze, prompt, value: "") : ""
+          prompt ? content_tag("option", prompt, value: "") : ""
         end
 
         # Builds hidden input tag for date part and value.
@@ -1135,7 +1135,7 @@ module ActionView
         # Given an ordering of datetime components, create the selection HTML
         # and join them with their appropriate separators.
         def build_selects_from_types(order)
-          select = "".dup
+          select = +""
           first_visible = order.find { |type| !@options[:"discard_#{type}"] }
           order.reverse_each do |type|
             separator = separator(type) unless type == first_visible # don't add before first visible field
diff --git a/actionview/lib/action_view/helpers/form_helper.rb b/actionview/lib/action_view/helpers/form_helper.rb
index 07f3d98322..6e769aa560 100644
--- a/actionview/lib/action_view/helpers/form_helper.rb
+++ b/actionview/lib/action_view/helpers/form_helper.rb
@@ -590,6 +590,9 @@ module ActionView
       #   Skipped if a <tt>:url</tt> is passed.
       # * <tt>:scope</tt> - The scope to prefix input field names with and
       #   thereby how the submitted parameters are grouped in controllers.
+      # * <tt>:namespace</tt> - A namespace for your form to ensure uniqueness of
+      #   id attributes on form elements. The namespace attribute will be prefixed
+      #   with underscore on the generated HTML id.
       # * <tt>:model</tt> - A model object to infer the <tt>:url</tt> and
       #   <tt>:scope</tt> by, plus fill out input field values.
       #   So if a +title+ attribute is set to "Ahoy!" then a +title+ input
diff --git a/actionview/lib/action_view/helpers/form_options_helper.rb b/actionview/lib/action_view/helpers/form_options_helper.rb
index 7884a8d997..ebdd96f570 100644
--- a/actionview/lib/action_view/helpers/form_options_helper.rb
+++ b/actionview/lib/action_view/helpers/form_options_helper.rb
@@ -463,7 +463,7 @@ module ActionView
           option_tags = options_from_collection_for_select(
             value_for_collection(group, group_method), option_key_method, option_value_method, selected_key)
 
-          content_tag("optgroup".freeze, option_tags, label: value_for_collection(group, group_label_method))
+          content_tag("optgroup", option_tags, label: value_for_collection(group, group_label_method))
         end.join.html_safe
       end
 
@@ -535,7 +535,7 @@ module ActionView
         body = "".html_safe
 
         if prompt
-          body.safe_concat content_tag("option".freeze, prompt_text(prompt), value: "")
+          body.safe_concat content_tag("option", prompt_text(prompt), value: "")
         end
 
         grouped_options.each do |container|
@@ -548,7 +548,7 @@ module ActionView
           end
 
           html_attributes = { label: label }.merge!(html_attributes)
-          body.safe_concat content_tag("optgroup".freeze, options_for_select(container, selected_key), html_attributes)
+          body.safe_concat content_tag("optgroup", options_for_select(container, selected_key), html_attributes)
         end
 
         body
@@ -584,7 +584,7 @@ module ActionView
           end
 
           zone_options.safe_concat options_for_select(convert_zones[priority_zones], selected)
-          zone_options.safe_concat content_tag("option".freeze, "-------------", value: "", disabled: true)
+          zone_options.safe_concat content_tag("option", "-------------", value: "", disabled: true)
           zone_options.safe_concat "\n"
 
           zones = zones - priority_zones
@@ -794,7 +794,7 @@ module ActionView
         def extract_values_from_collection(collection, value_method, selected)
           if selected.is_a?(Proc)
             collection.map do |element|
-              element.send(value_method) if selected.call(element)
+              public_or_deprecated_send(element, value_method) if selected.call(element)
             end.compact
           else
             selected
@@ -802,7 +802,15 @@ module ActionView
         end
 
         def value_for_collection(item, value)
-          value.respond_to?(:call) ? value.call(item) : item.send(value)
+          value.respond_to?(:call) ? value.call(item) : public_or_deprecated_send(item, value)
+        end
+
+        def public_or_deprecated_send(item, value)
+          item.public_send(value)
+        rescue NoMethodError
+          raise unless item.respond_to?(value, true) && !item.respond_to?(value)
+          ActiveSupport::Deprecation.warn "Using private methods from view helpers is deprecated (calling private #{item.class}##{value})"
+          item.send(value)
         end
 
         def prompt_text(prompt)
diff --git a/actionview/lib/action_view/helpers/form_tag_helper.rb b/actionview/lib/action_view/helpers/form_tag_helper.rb
index ba09738beb..c0996049f0 100644
--- a/actionview/lib/action_view/helpers/form_tag_helper.rb
+++ b/actionview/lib/action_view/helpers/form_tag_helper.rb
@@ -146,15 +146,15 @@ module ActionView
           end
 
           if include_blank
-            option_tags = content_tag("option".freeze, include_blank, options_for_blank_options_tag).safe_concat(option_tags)
+            option_tags = content_tag("option", include_blank, options_for_blank_options_tag).safe_concat(option_tags)
           end
         end
 
         if prompt = options.delete(:prompt)
-          option_tags = content_tag("option".freeze, prompt, value: "").safe_concat(option_tags)
+          option_tags = content_tag("option", prompt, value: "").safe_concat(option_tags)
         end
 
-        content_tag "select".freeze, option_tags, { "name" => html_name, "id" => sanitize_to_id(name) }.update(options.stringify_keys)
+        content_tag "select", option_tags, { "name" => html_name, "id" => sanitize_to_id(name) }.update(options.stringify_keys)
       end
 
       # Creates a standard text field; use these text fields to input smaller chunks of text like a username
@@ -577,7 +577,7 @@ module ActionView
       #   # => <fieldset class="format"><p><input id="name" name="name" type="text" /></p></fieldset>
       def field_set_tag(legend = nil, options = nil, &block)
         output = tag(:fieldset, options, true)
-        output.safe_concat(content_tag("legend".freeze, legend)) unless legend.blank?
+        output.safe_concat(content_tag("legend", legend)) unless legend.blank?
         output.concat(capture(&block)) if block_given?
         output.safe_concat("</fieldset>")
       end
diff --git a/actionview/lib/action_view/helpers/javascript_helper.rb b/actionview/lib/action_view/helpers/javascript_helper.rb
index 830088bea3..b680cb1bd3 100644
--- a/actionview/lib/action_view/helpers/javascript_helper.rb
+++ b/actionview/lib/action_view/helpers/javascript_helper.rb
@@ -15,8 +15,8 @@ module ActionView
         "'"     => "\\'"
       }
 
-      JS_ESCAPE_MAP["\342\200\250".dup.force_encoding(Encoding::UTF_8).encode!] = "&#x2028;"
-      JS_ESCAPE_MAP["\342\200\251".dup.force_encoding(Encoding::UTF_8).encode!] = "&#x2029;"
+      JS_ESCAPE_MAP[(+"\342\200\250").force_encoding(Encoding::UTF_8).encode!] = "&#x2028;"
+      JS_ESCAPE_MAP[(+"\342\200\251").force_encoding(Encoding::UTF_8).encode!] = "&#x2029;"
 
       # Escapes carriage returns and single and double quotes for JavaScript segments.
       #
@@ -25,12 +25,13 @@ module ActionView
       #
       #   $('some_element').replaceWith('<%= j render 'some/element_template' %>');
       def escape_javascript(javascript)
-        if javascript
-          result = javascript.gsub(/(\\|<\/|\r\n|\342\200\250|\342\200\251|[\n\r"'])/u) { |match| JS_ESCAPE_MAP[match] }
-          javascript.html_safe? ? result.html_safe : result
+        javascript = javascript.to_s
+        if javascript.empty?
+          result = ""
         else
-          ""
+          result = javascript.gsub(/(\\|<\/|\r\n|\342\200\250|\342\200\251|[\n\r"'])/u) { |match| JS_ESCAPE_MAP[match] }
         end
+        javascript.html_safe? ? result.html_safe : result
       end
 
       alias_method :j, :escape_javascript
@@ -83,7 +84,7 @@ module ActionView
           html_options[:nonce] = content_security_policy_nonce
         end
 
-        content_tag("script".freeze, javascript_cdata_section(content), html_options)
+        content_tag("script", javascript_cdata_section(content), html_options)
       end
 
       def javascript_cdata_section(content) #:nodoc:
diff --git a/actionview/lib/action_view/helpers/number_helper.rb b/actionview/lib/action_view/helpers/number_helper.rb
index 4b53b8fe6e..35206b7e48 100644
--- a/actionview/lib/action_view/helpers/number_helper.rb
+++ b/actionview/lib/action_view/helpers/number_helper.rb
@@ -100,6 +100,9 @@ module ActionView
       #   absolute value of the number.
       # * <tt>:raise</tt> - If true, raises +InvalidNumberError+ when
       #   the argument is invalid.
+      # * <tt>:strip_insignificant_zeros</tt> - If +true+ removes
+      #   insignificant zeros after the decimal separator (defaults to
+      #   +false+).
       #
       # ==== Examples
       #
@@ -117,6 +120,8 @@ module ActionView
       #   # => R$1234567890,50
       #   number_to_currency(1234567890.50, unit: "R$", separator: ",", delimiter: "", format: "%n %u")
       #   # => 1234567890,50 R$
+      #   number_to_currency(1234567890.50, strip_insignificant_zeros: true)
+      #   # => "$1,234,567,890.5"
       def number_to_currency(number, options = {})
         delegate_number_helper_method(:number_to_currency, number, options)
       end
diff --git a/actionview/lib/action_view/helpers/sanitize_helper.rb b/actionview/lib/action_view/helpers/sanitize_helper.rb
index cb0c99c4cf..f4fa133f55 100644
--- a/actionview/lib/action_view/helpers/sanitize_helper.rb
+++ b/actionview/lib/action_view/helpers/sanitize_helper.rb
@@ -10,7 +10,7 @@ module ActionView
     # These helper methods extend Action View making them callable within your template files.
     module SanitizeHelper
       extend ActiveSupport::Concern
-      # Sanitizes HTML input, stripping all tags and attributes that aren't whitelisted.
+      # Sanitizes HTML input, stripping all but known-safe tags and attributes.
       #
       # It also strips href/src attributes with unsafe protocols like
       # <tt>javascript:</tt>, while also protecting against attempts to use Unicode,
@@ -40,7 +40,7 @@ module ActionView
       #
       #   <%= sanitize @comment.body %>
       #
-      # Providing custom whitelisted tags and attributes:
+      # Providing custom lists of permitted tags and attributes:
       #
       #   <%= sanitize @comment.body, tags: %w(strong em a), attributes: %w(href) %>
       #
diff --git a/actionview/lib/action_view/helpers/tag_helper.rb b/actionview/lib/action_view/helpers/tag_helper.rb
index d12989ea64..3979721d34 100644
--- a/actionview/lib/action_view/helpers/tag_helper.rb
+++ b/actionview/lib/action_view/helpers/tag_helper.rb
@@ -58,7 +58,7 @@ module ActionView
 
         def tag_options(options, escape = true)
           return if options.blank?
-          output = "".dup
+          output = +""
           sep    = " "
           options.each_pair do |key, value|
             if TAG_PREFIXES.include?(key) && value.is_a?(Hash)
@@ -86,11 +86,11 @@ module ActionView
 
         def tag_option(key, value, escape)
           if value.is_a?(Array)
-            value = escape ? safe_join(value, " ".freeze) : value.join(" ".freeze)
+            value = escape ? safe_join(value, " ") : value.join(" ")
           else
             value = escape ? ERB::Util.unwrapped_html_escape(value) : value.to_s.dup
           end
-          value.gsub!('"'.freeze, "&quot;".freeze)
+          value.gsub!('"', "&quot;")
           %(#{key}="#{value}")
         end
 
diff --git a/actionview/lib/action_view/helpers/text_helper.rb b/actionview/lib/action_view/helpers/text_helper.rb
index 77a1c1fed9..a338d076e4 100644
--- a/actionview/lib/action_view/helpers/text_helper.rb
+++ b/actionview/lib/action_view/helpers/text_helper.rb
@@ -228,7 +228,7 @@ module ActionView
       #   pluralize(2, 'Person', locale: :de)
       #   # => 2 Personen
       def pluralize(count, singular, plural_arg = nil, plural: plural_arg, locale: I18n.locale)
-        word = if (count == 1 || count =~ /^1(\.0+)?$/)
+        word = if count == 1 || count =~ /^1(\.0+)?$/
           singular
         else
           plural || singular.pluralize(locale)
diff --git a/actionview/lib/action_view/helpers/translation_helper.rb b/actionview/lib/action_view/helpers/translation_helper.rb
index ba82dcab3e..ae1c93e12f 100644
--- a/actionview/lib/action_view/helpers/translation_helper.rb
+++ b/actionview/lib/action_view/helpers/translation_helper.rb
@@ -98,7 +98,7 @@ module ActionView
           raise e if raise_error
 
           keys = I18n.normalize_keys(e.locale, e.key, e.options[:scope])
-          title = "translation missing: #{keys.join('.')}".dup
+          title = +"translation missing: #{keys.join('.')}"
 
           interpolations = options.except(:default, :scope)
           if interpolations.any?
diff --git a/actionview/lib/action_view/helpers/url_helper.rb b/actionview/lib/action_view/helpers/url_helper.rb
index 52bffaab84..948dd1551f 100644
--- a/actionview/lib/action_view/helpers/url_helper.rb
+++ b/actionview/lib/action_view/helpers/url_helper.rb
@@ -200,9 +200,9 @@ module ActionView
         html_options = convert_options_to_data_attributes(options, html_options)
 
         url = url_for(options)
-        html_options["href".freeze] ||= url
+        html_options["href"] ||= url
 
-        content_tag("a".freeze, name || url, html_options, &block)
+        content_tag("a", name || url, html_options, &block)
       end
 
       # Generates a form containing a single button that submits to the URL created
@@ -308,7 +308,7 @@ module ActionView
         params = html_options.delete("params")
 
         method     = html_options.delete("method").to_s
-        method_tag = BUTTON_TAG_METHOD_VERBS.include?(method) ? method_tag(method) : "".freeze.html_safe
+        method_tag = BUTTON_TAG_METHOD_VERBS.include?(method) ? method_tag(method) : "".html_safe
 
         form_method  = method == "get" ? "get" : "post"
         form_options = html_options.delete("form") || {}
@@ -321,7 +321,7 @@ module ActionView
           request_method = method.empty? ? "post" : method
           token_tag(nil, form_options: { action: url, method: request_method })
         else
-          "".freeze
+          ""
         end
 
         html_options = convert_options_to_data_attributes(options, html_options)
@@ -487,12 +487,12 @@ module ActionView
           option = html_options.delete(item).presence || next
           "#{item.dasherize}=#{ERB::Util.url_encode(option)}"
         }.compact
-        extras = extras.empty? ? "".freeze : "?" + extras.join("&")
+        extras = extras.empty? ? "" : "?" + extras.join("&")
 
         encoded_email_address = ERB::Util.url_encode(email_address).gsub("%40", "@")
         html_options["href"] = "mailto:#{encoded_email_address}#{extras}"
 
-        content_tag("a".freeze, name || email_address, html_options, &block)
+        content_tag("a", name || email_address, html_options, &block)
       end
 
       # True if the current request URI was generated by the given +options+.
@@ -575,21 +575,21 @@ module ActionView
         def convert_options_to_data_attributes(options, html_options)
           if html_options
             html_options = html_options.stringify_keys
-            html_options["data-remote"] = "true".freeze if link_to_remote_options?(options) || link_to_remote_options?(html_options)
+            html_options["data-remote"] = "true" if link_to_remote_options?(options) || link_to_remote_options?(html_options)
 
-            method = html_options.delete("method".freeze)
+            method = html_options.delete("method")
 
             add_method_to_attributes!(html_options, method) if method
 
             html_options
           else
-            link_to_remote_options?(options) ? { "data-remote" => "true".freeze } : {}
+            link_to_remote_options?(options) ? { "data-remote" => "true" } : {}
           end
         end
 
         def link_to_remote_options?(options)
           if options.is_a?(Hash)
-            options.delete("remote".freeze) || options.delete(:remote)
+            options.delete("remote") || options.delete(:remote)
           end
         end
 
@@ -622,7 +622,7 @@ module ActionView
             token ||= form_authenticity_token(form_options: form_options)
             tag(:input, type: "hidden", name: request_forgery_protection_token.to_s, value: token)
           else
-            "".freeze
+            ""
           end
         end
 
diff --git a/actionview/lib/action_view/log_subscriber.rb b/actionview/lib/action_view/log_subscriber.rb
index d4ac77e10f..db07b9d7fb 100644
--- a/actionview/lib/action_view/log_subscriber.rb
+++ b/actionview/lib/action_view/log_subscriber.rb
@@ -16,7 +16,7 @@ module ActionView
 
     def render_template(event)
       info do
-        message = "  Rendered #{from_rails_root(event.payload[:identifier])}".dup
+        message = +"  Rendered #{from_rails_root(event.payload[:identifier])}"
         message << " within #{from_rails_root(event.payload[:layout])}" if event.payload[:layout]
         message << " (#{event.duration.round(1)}ms)"
       end
@@ -24,7 +24,7 @@ module ActionView
 
     def render_partial(event)
       info do
-        message = "  Rendered #{from_rails_root(event.payload[:identifier])}".dup
+        message = +"  Rendered #{from_rails_root(event.payload[:identifier])}"
         message << " within #{from_rails_root(event.payload[:layout])}" if event.payload[:layout]
         message << " (#{event.duration.round(1)}ms)"
         message << " #{cache_message(event.payload)}" unless event.payload[:cache_hit].nil?
@@ -85,7 +85,7 @@ module ActionView
 
     def log_rendering_start(payload)
       info do
-        message = "  Rendering #{from_rails_root(payload[:identifier])}".dup
+        message = +"  Rendering #{from_rails_root(payload[:identifier])}"
         message << " within #{from_rails_root(payload[:layout])}" if payload[:layout]
         message
       end
diff --git a/actionview/lib/action_view/lookup_context.rb b/actionview/lib/action_view/lookup_context.rb
index 0e56eca35c..af67ffa12d 100644
--- a/actionview/lib/action_view/lookup_context.rb
+++ b/actionview/lib/action_view/lookup_context.rb
@@ -202,13 +202,13 @@ module ActionView
       # name instead of the prefix.
       def normalize_name(name, prefixes)
         prefixes = prefixes.presence
-        parts    = name.to_s.split("/".freeze)
+        parts    = name.to_s.split("/")
         parts.shift if parts.first.empty?
         name = parts.pop
 
         return name, prefixes || [""] if parts.empty?
 
-        parts    = parts.join("/".freeze)
+        parts    = parts.join("/")
         prefixes = prefixes ? prefixes.map { |p| "#{p}/#{parts}" } : [parts]
 
         return name, prefixes
@@ -245,7 +245,7 @@ module ActionView
     # add :html as fallback to :js.
     def formats=(values)
       if values
-        values.concat(default_formats) if values.delete "*/*".freeze
+        values.concat(default_formats) if values.delete "*/*"
         if values == [:js]
           values << :html
           @html_fallback_for_js = true
diff --git a/actionview/lib/action_view/record_identifier.rb b/actionview/lib/action_view/record_identifier.rb
index 1310a1ce0a..ee39b6050d 100644
--- a/actionview/lib/action_view/record_identifier.rb
+++ b/actionview/lib/action_view/record_identifier.rb
@@ -59,8 +59,8 @@ module ActionView
 
     include ModelNaming
 
-    JOIN = "_".freeze
-    NEW = "new".freeze
+    JOIN = "_"
+    NEW = "new"
 
     # The DOM class convention is to use the singular form of an object or class.
     #
diff --git a/actionview/lib/action_view/renderer/partial_renderer.rb b/actionview/lib/action_view/renderer/partial_renderer.rb
index d7f97c3b50..cb850d75ee 100644
--- a/actionview/lib/action_view/renderer/partial_renderer.rb
+++ b/actionview/lib/action_view/renderer/partial_renderer.rb
@@ -523,7 +523,7 @@ module ActionView
 
       def retrieve_variable(path, as)
         variable = as || begin
-          base = path[-1] == "/".freeze ? "".freeze : File.basename(path)
+          base = path[-1] == "/" ? "" : File.basename(path)
           raise_invalid_identifier(path) unless base =~ /\A_?(.*?)(?:\.\w+)*\z/
           $1.to_sym
         end
diff --git a/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb b/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb
index db52919e91..5aa6f77902 100644
--- a/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb
+++ b/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb
@@ -14,15 +14,35 @@ module ActionView
       def cache_collection_render(instrumentation_payload)
         return yield unless @options[:cached]
 
+        # Result is a hash with the key represents the
+        # key used for cache lookup and the value is the item
+        # on which the partial is being rendered
         keyed_collection = collection_by_cache_keys
+
+        # Pull all partials from cache
+        # Result is a hash, key matches the entry in
+        # `keyed_collection` where the cache was retrieved and the
+        # value is the value that was present in the cache
         cached_partials  = collection_cache.read_multi(*keyed_collection.keys)
         instrumentation_payload[:cache_hits] = cached_partials.size
 
+        # Extract the items for the keys that are not found
+        # Set the uncached values to instance variable @collection
+        # which is used by the caller
         @collection = keyed_collection.reject { |key, _| cached_partials.key?(key) }.values
+
+        # If all elements are already in cache then
+        # rendered partials will be an empty array
+        #
+        # If the cache is missing elements then
+        # the block will be called against the remaining items
+        # in the @collection.
         rendered_partials = @collection.empty? ? [] : yield
 
         index = 0
         fetch_or_cache_partial(cached_partials, order_by: keyed_collection.each_key) do
+          # This block is called once
+          # for every cache miss while preserving order.
           rendered_partials[index].tap { index += 1 }
         end
       end
@@ -40,10 +60,29 @@ module ActionView
       end
 
       def expanded_cache_key(key)
-        key = @view.combined_fragment_cache_key(@view.cache_fragment_name(key, virtual_path: @template.virtual_path))
+        key = @view.combined_fragment_cache_key(@view.cache_fragment_name(key, virtual_path: @template.virtual_path, digest_path: digest_path))
         key.frozen? ? key.dup : key # #read_multi & #write may require mutability, Dalli 2.6.0.
       end
 
+      def digest_path
+        @digest_path ||= @view.digest_path_from_virtual(@template.virtual_path)
+      end
+
+      # `order_by` is an enumerable object containing keys of the cache,
+      # all keys are  passed in whether found already or not.
+      #
+      # `cached_partials` is a hash. If the value exists
+      # it represents the rendered partial from the cache
+      # otherwise `Hash#fetch` will take the value of its block.
+      #
+      # This method expects a block that will return the rendered
+      # partial. An example is to render all results
+      # for each element that was not found in the cache and store it as an array.
+      # Order it so that the first empty cache element in `cached_partials`
+      # corresponds to the first element in `rendered_partials`.
+      #
+      # If the partial is not already cached it will also be
+      # written back to the underlying cache store.
       def fetch_or_cache_partial(cached_partials, order_by:)
         order_by.map do |cache_key|
           cached_partials.fetch(cache_key) do
diff --git a/actionview/lib/action_view/renderer/streaming_template_renderer.rb b/actionview/lib/action_view/renderer/streaming_template_renderer.rb
index 276a28ce07..bb9db21e32 100644
--- a/actionview/lib/action_view/renderer/streaming_template_renderer.rb
+++ b/actionview/lib/action_view/renderer/streaming_template_renderer.rb
@@ -33,7 +33,7 @@ module ActionView
           logger = ActionView::Base.logger
           return unless logger
 
-          message = "\n#{exception.class} (#{exception.message}):\n".dup
+          message = +"\n#{exception.class} (#{exception.message}):\n"
           message << exception.annoted_source_code.to_s if exception.respond_to?(:annoted_source_code)
           message << "  " << exception.backtrace.join("\n  ")
           logger.fatal("#{message}\n\n")
diff --git a/actionview/lib/action_view/template.rb b/actionview/lib/action_view/template.rb
index ee1cd61f12..d7aee18a84 100644
--- a/actionview/lib/action_view/template.rb
+++ b/actionview/lib/action_view/template.rb
@@ -188,7 +188,7 @@ module ActionView
     end
 
     def inspect
-      @inspect ||= defined?(Rails.root) ? identifier.sub("#{Rails.root}/", "".freeze) : identifier
+      @inspect ||= defined?(Rails.root) ? identifier.sub("#{Rails.root}/", "") : identifier
     end
 
     # This method is responsible for properly setting the encoding of the
@@ -235,6 +235,19 @@ module ActionView
       end
     end
 
+    
+    # Exceptions are marshalled when using the parallel test runner with DRb, so we need
+    # to ensure that references to the template object can be marshalled as well. This means forgoing
+    # the marshalling of the compiler mutex and instantiating that again on unmarshalling.
+    def marshal_dump # :nodoc:
+      [ @source, @identifier, @handler, @compiled, @original_encoding, @locals, @virtual_path, @updated_at, @formats, @variants ]
+    end
+
+    def marshal_load(array) # :nodoc:
+      @source, @identifier, @handler, @compiled, @original_encoding, @locals, @virtual_path, @updated_at, @formats, @variants = *array
+      @compile_mutex = Mutex.new
+    end
+
     private
 
       # Compile a template. This method ensures a template is compiled
@@ -286,7 +299,7 @@ module ActionView
 
         # Make sure that the resulting String to be eval'd is in the
         # encoding of the code
-        source = <<-end_src.dup
+        source = +<<-end_src
           def #{method_name}(local_assigns, output_buffer)
             _old_virtual_path, @virtual_path = @virtual_path, #{@virtual_path.inspect};_old_output_buffer = @output_buffer;#{locals_code};#{code}
           ensure
@@ -335,19 +348,19 @@ module ActionView
         locals = locals.grep(/\A@?(?![A-Z0-9])(?:[[:alnum:]_]|[^\0-\177])+\z/)
 
         # Assign for the same variable is to suppress unused variable warning
-        locals.each_with_object("".dup) { |key, code| code << "#{key} = local_assigns[:#{key}]; #{key} = #{key};" }
+        locals.each_with_object(+"") { |key, code| code << "#{key} = local_assigns[:#{key}]; #{key} = #{key};" }
       end
 
       def method_name
         @method_name ||= begin
-          m = "_#{identifier_method_name}__#{@identifier.hash}_#{__id__}".dup
-          m.tr!("-".freeze, "_".freeze)
+          m = +"_#{identifier_method_name}__#{@identifier.hash}_#{__id__}"
+          m.tr!("-", "_")
           m
         end
       end
 
       def identifier_method_name
-        inspect.tr("^a-z_".freeze, "_".freeze)
+        inspect.tr("^a-z_", "_")
       end
 
       def instrument(action, &block) # :doc:
@@ -355,7 +368,7 @@ module ActionView
       end
 
       def instrument_render_template(&block)
-        ActiveSupport::Notifications.instrument("!render_template.action_view".freeze, instrument_payload, &block)
+        ActiveSupport::Notifications.instrument("!render_template.action_view", instrument_payload, &block)
       end
 
       def instrument_payload
diff --git a/actionview/lib/action_view/template/handlers/erb.rb b/actionview/lib/action_view/template/handlers/erb.rb
index b7b749f9da..270be0a380 100644
--- a/actionview/lib/action_view/template/handlers/erb.rb
+++ b/actionview/lib/action_view/template/handlers/erb.rb
@@ -14,7 +14,17 @@ module ActionView
         class_attribute :erb_implementation, default: Erubi
 
         # Do not escape templates of these mime types.
-        class_attribute :escape_whitelist, default: ["text/plain"]
+        class_attribute :escape_ignore_list, default: ["text/plain"]
+
+        [self, singleton_class].each do |base|
+          base.send(:alias_method, :escape_whitelist, :escape_ignore_list)
+          base.send(:alias_method, :escape_whitelist=, :escape_ignore_list=)
+
+          base.deprecate(
+            escape_whitelist: "use #escape_ignore_list instead",
+            :escape_whitelist= => "use #escape_ignore_list= instead"
+          )
+        end
 
         ENCODING_TAG = Regexp.new("\\A(<%#{ENCODING_FLAG}-?%>)[ \\t]*")
 
@@ -47,7 +57,7 @@ module ActionView
 
           self.class.erb_implementation.new(
             erb,
-            escape: (self.class.escape_whitelist.include? template.type),
+            escape: (self.class.escape_ignore_list.include? template.type),
             trim: (self.class.erb_trim_mode == "-")
           ).src
         end
diff --git a/actionview/lib/action_view/template/resolver.rb b/actionview/lib/action_view/template/resolver.rb
index 5a86f10973..08dd6fb510 100644
--- a/actionview/lib/action_view/template/resolver.rb
+++ b/actionview/lib/action_view/template/resolver.rb
@@ -16,7 +16,7 @@ module ActionView
       alias_method :partial?, :partial
 
       def self.build(name, prefix, partial)
-        virtual = "".dup
+        virtual = +""
         virtual << "#{prefix}/" unless prefix.empty?
         virtual << (partial ? "_#{name}" : name)
         new name, prefix, partial, virtual
@@ -221,9 +221,7 @@ module ActionView
       end
 
       def query(path, details, formats, outside_app_allowed)
-        query = build_query(path, details)
-
-        template_paths = find_template_paths(query)
+        template_paths = find_template_paths_from_details(path, details)
         template_paths = reject_files_external_to_app(template_paths) unless outside_app_allowed
 
         template_paths.map do |template|
@@ -243,6 +241,11 @@ module ActionView
         files.reject { |filename| !inside_path?(@path, filename) }
       end
 
+      def find_template_paths_from_details(path, details)
+        query = build_query(path, details)
+        find_template_paths(query)
+      end
+
       def find_template_paths(query)
         Dir[query].uniq.reject do |filename|
           File.directory?(filename) ||
@@ -279,7 +282,7 @@ module ActionView
       end
 
       def escape_entry(entry)
-        entry.gsub(/[*?{}\[\]]/, '\\\\\\&'.freeze)
+        entry.gsub(/[*?{}\[\]]/, '\\\\\\&')
       end
 
       # Returns the file mtime from the filesystem.
@@ -291,7 +294,7 @@ module ActionView
       # from the path, or the handler, we should return the array of formats given
       # to the resolver.
       def extract_handler_and_format_and_variant(path)
-        pieces = File.basename(path).split(".".freeze)
+        pieces = File.basename(path).split(".")
         pieces.shift
 
         extension = pieces.pop
@@ -362,19 +365,56 @@ module ActionView
 
   # An Optimized resolver for Rails' most common case.
   class OptimizedFileSystemResolver < FileSystemResolver #:nodoc:
-    def build_query(path, details)
-      query = escape_entry(File.join(@path, path))
+    private
 
-      exts = EXTENSIONS.map do |ext, prefix|
-        if ext == :variants && details[ext] == :any
-          "{#{prefix}*,}"
-        else
-          "{#{details[ext].compact.uniq.map { |e| "#{prefix}#{e}," }.join}}"
+      def find_template_paths_from_details(path, details)
+        # Instead of checking for every possible path, as our other globs would
+        # do, scan the directory for files with the right prefix.
+        query = "#{escape_entry(File.join(@path, path))}*"
+
+        regex = build_regex(path, details)
+
+        Dir[query].uniq.reject do |filename|
+          # This regex match does double duty of finding only files which match
+          # details (instead of just matching the prefix) and also filtering for
+          # case-insensitive file systems.
+          !filename.match(regex) ||
+            File.directory?(filename)
+        end.sort_by do |filename|
+          # Because we scanned the directory, instead of checking for files
+          # one-by-one, they will be returned in an arbitrary order.
+          # We can use the matches found by the regex and sort by their index in
+          # details.
+          match = filename.match(regex)
+          EXTENSIONS.keys.reverse.map do |ext|
+            if ext == :variants && details[ext] == :any
+              match[ext].nil? ? 0 : 1
+            elsif match[ext].nil?
+              # No match should be last
+              details[ext].length
+            else
+              found = match[ext].to_sym
+              details[ext].index(found)
+            end
+          end
         end
-      end.join
+      end
 
-      query + exts
-    end
+      def build_regex(path, details)
+        query = escape_entry(File.join(@path, path))
+        exts = EXTENSIONS.map do |ext, prefix|
+          match =
+            if ext == :variants && details[ext] == :any
+              ".*?"
+            else
+              details[ext].compact.uniq.map { |e| Regexp.escape(e) }.join("|")
+            end
+          prefix = Regexp.escape(prefix)
+          "(#{prefix}(?<#{ext}>#{match}))?"
+        end.join
+
+        %r{\A#{query}#{exts}\z}
+      end
   end
 
   # The same as FileSystemResolver but does not allow templates to store
diff --git a/actionview/lib/action_view/test_case.rb b/actionview/lib/action_view/test_case.rb
index e1cbae5845..e14f7aaec7 100644
--- a/actionview/lib/action_view/test_case.rb
+++ b/actionview/lib/action_view/test_case.rb
@@ -107,7 +107,7 @@ module ActionView
         # empty string ensures buffer has UTF-8 encoding as
         # new without arguments returns ASCII-8BIT encoded buffer like String#new
         @output_buffer = ActiveSupport::SafeBuffer.new ""
-        @rendered = "".dup
+        @rendered = +""
 
         make_test_case_available_to_view!
         say_no_to_protect_against_forgery!
diff --git a/actionview/lib/action_view/testing/resolvers.rb b/actionview/lib/action_view/testing/resolvers.rb
index 68186c3bf8..1fad08a689 100644
--- a/actionview/lib/action_view/testing/resolvers.rb
+++ b/actionview/lib/action_view/testing/resolvers.rb
@@ -22,7 +22,7 @@ module ActionView #:nodoc:
     private
 
       def query(path, exts, _, _)
-        query = "".dup
+        query = +""
         EXTENSIONS.each_key do |ext|
           query << "(" << exts[ext].map { |e| e && Regexp.escape(".#{e}") }.join("|") << "|)"
         end