Merge branch 'master' into treewip

* master: (113 commits)
  remove useless method
  Updated file documentation [ci skip]
  changes caching guide to add note on weak etags
  Don't put config.action_mailer.perform_caching entry twice in development.rb
  Fix wording and wrong reference
  Add Ruby formatting to CHANGELOG entry
  Fix ActionView's cache section reference
  Do not define methods in the included block
  Add caching guide in ActionMailer basics
  Add ActionMailer configuration options
  Preparing for 5.0.0.beta3 release
  Update 5.0 release notes
  Enable tmp_restart plugin for puma
  Prep release for Rails 5 beta3
  [ci skip] Move collection caching changelog entry.
  Ensure `drop_table` even if tests failure or interrupted
  :bomb: run the test @rafaelfranca :angry:
  Remove changelog entry for reverted commit
  Add CHANGELOG for https://github.com/rails/rails/pull/23734 [ci skip]
  No need CHANGELOG entry for #23849.
  ...

11 files changed, 70 insertions, 135 deletions

diff --git a/actionview/lib/action_view/gem_version.rb b/actionview/lib/action_view/gem_version.rb
index bb5c96cb39..efb565bf59 100644
--- a/actionview/lib/action_view/gem_version.rb
+++ b/actionview/lib/action_view/gem_version.rb
@@ -8,7 +8,7 @@ module ActionView
     MAJOR = 5
     MINOR = 0
     TINY  = 0
-    PRE   = "beta2"
+    PRE   = "beta3"
 
     STRING = [MAJOR, MINOR, TINY, PRE].compact.join(".")
   end
diff --git a/actionview/lib/action_view/helpers/cache_helper.rb b/actionview/lib/action_view/helpers/cache_helper.rb
index 401f398721..4c7c4b91c6 100644
--- a/actionview/lib/action_view/helpers/cache_helper.rb
+++ b/actionview/lib/action_view/helpers/cache_helper.rb
@@ -126,44 +126,29 @@ module ActionView
       #
       # Now all you have to do is change that timestamp when the helper method changes.
       #
-      # === Automatic Collection Caching
+      # === Collection Caching
       #
-      # When rendering collections such as:
+      # When rendering a collection of objects that each use the same partial, a `cached`
+      # option can be passed.
+      # For collections rendered such:
       #
-      #   <%= render @notifications %>
-      #   <%= render partial: 'notifications/notification', collection: @notifications %>
+      #   <%= render partial: 'notifications/notification', collection: @notifications, cached: true %>
       #
-      # If the notifications/_notification partial starts with a cache call as:
+      # The `cached: true` will make Action View's rendering read several templates
+      # from cache at once instead of one call per template.
       #
-      #   <% cache notification do %>
-      #     <%= notification.name %>
-      #   <% end %>
-      #
-      # The collection can then automatically use any cached renders for that
-      # template by reading them at once instead of one by one.
-      #
-      # See ActionView::Template::Handlers::ERB.resource_cache_call_pattern for
-      # more information on what cache calls make a template eligible for this
-      # collection caching.
-      #
-      # The automatic cache multi read can be turned off like so:
+      # Templates in the collection not already cached are written to cache.
       #
-      #   <%= render @notifications, cache: false %>
+      # Works great alongside individual template fragment caching.
+      # For instance if the template the collection renders is cached like:
       #
-      # === Explicit Collection Caching
-      #
-      # If the partial template doesn't start with a clean cache call as
-      # mentioned above, you can still benefit from collection caching by
-      # adding a special comment format anywhere in the template, like:
-      #
-      #   <%# Template Collection: notification %>
-      #   <% my_helper_that_calls_cache(some_arg, notification) do %>
-      #     <%= notification.name %>
+      #   # notifications/_notification.html.erb
+      #   <% cache notification do %>
+      #     <%# ... %>
       #   <% end %>
       #
-      # The pattern used to match these is <tt>/# Template Collection: (\S+)/</tt>,
-      # so it's important that you type it out just so.
-      # You can only declare one collection in a partial template file.
+      # Any collection renders will find those cached templates when attempting
+      # to read multiple templates at once.
       def cache(name = {}, options = {}, &block)
         if controller.respond_to?(:perform_caching) && controller.perform_caching
           name_options = options.slice(:skip_digest, :virtual_path)
diff --git a/actionview/lib/action_view/helpers/form_tag_helper.rb b/actionview/lib/action_view/helpers/form_tag_helper.rb
index 55dac74d00..82e9ace428 100644
--- a/actionview/lib/action_view/helpers/form_tag_helper.rb
+++ b/actionview/lib/action_view/helpers/form_tag_helper.rb
@@ -862,13 +862,13 @@ module ActionView
 
         def extra_tags_for_form(html_options)
           authenticity_token = html_options.delete("authenticity_token")
-          method = html_options.delete("method").to_s
+          method = html_options.delete("method").to_s.downcase
 
           method_tag = case method
-            when /^get$/i # must be case-insensitive, but can't use downcase as might be nil
+            when 'get'
               html_options["method"] = "get"
               ''
-            when /^post$/i, "", nil
+            when 'post', ''
               html_options["method"] = "post"
               token_tag(authenticity_token, form_options: {
                 action: html_options["action"],
diff --git a/actionview/lib/action_view/helpers/url_helper.rb b/actionview/lib/action_view/helpers/url_helper.rb
index 87218821ed..ab67923376 100644
--- a/actionview/lib/action_view/helpers/url_helper.rb
+++ b/actionview/lib/action_view/helpers/url_helper.rb
@@ -312,7 +312,8 @@ module ActionView
         form_options[:'data-remote'] = true if remote
 
         request_token_tag = if form_method == 'post'
-          token_tag(nil, form_options: form_options)
+          request_method = method.empty? ? 'post' : method
+          token_tag(nil, form_options: { action: url, method: request_method })
         else
           ''
         end
diff --git a/actionview/lib/action_view/log_subscriber.rb b/actionview/lib/action_view/log_subscriber.rb
index 9047dbdd85..aa38db2a3a 100644
--- a/actionview/lib/action_view/log_subscriber.rb
+++ b/actionview/lib/action_view/log_subscriber.rb
@@ -20,7 +20,15 @@ module ActionView
       end
     end
     alias :render_partial :render_template
-    alias :render_collection :render_template
+
+    def render_collection(event)
+      identifier = event.payload[:identifier] || 'templates'
+
+      info do
+        "  Rendered collection of #{from_rails_root(identifier)}" \
+        " #{render_count(event.payload)} (#{event.duration.round(1)}ms)"
+      end
+    end
 
     def logger
       ActionView::Base.logger
@@ -38,6 +46,14 @@ module ActionView
     def rails_root
       @root ||= "#{Rails.root}/"
     end
+
+    def render_count(payload)
+      if payload[:cache_hits]
+        "[#{payload[:cache_hits]} / #{payload[:count]} cache hits]"
+      else
+        "[#{payload[:count]} times]"
+      end
+    end
   end
 end
 
diff --git a/actionview/lib/action_view/lookup_context.rb b/actionview/lib/action_view/lookup_context.rb
index 86afedaa2d..4163e69a72 100644
--- a/actionview/lib/action_view/lookup_context.rb
+++ b/actionview/lib/action_view/lookup_context.rb
@@ -70,8 +70,6 @@ module ActionView
         @details_keys.clear
       end
 
-      def self.empty?; @details_keys.empty?; end
-
       def self.digest_caches
         @details_keys.values.map(&:digest_cache)
       end
diff --git a/actionview/lib/action_view/renderer/abstract_renderer.rb b/actionview/lib/action_view/renderer/abstract_renderer.rb
index aa77a77acf..23e672a95f 100644
--- a/actionview/lib/action_view/renderer/abstract_renderer.rb
+++ b/actionview/lib/action_view/renderer/abstract_renderer.rb
@@ -35,8 +35,12 @@ module ActionView
       end
     end
 
-    def instrument(name, options={})
-      ActiveSupport::Notifications.instrument("render_#{name}.action_view", options){ yield }
+    def instrument(name, **options)
+      options[:identifier] ||= (@template && @template.identifier) || @path
+
+      ActiveSupport::Notifications.instrument("render_#{name}.action_view", options) do |payload|
+        yield payload
+      end
     end
 
     def prepend_formats(formats)
diff --git a/actionview/lib/action_view/renderer/partial_renderer.rb b/actionview/lib/action_view/renderer/partial_renderer.rb
index a9bd257e76..514804b08e 100644
--- a/actionview/lib/action_view/renderer/partial_renderer.rb
+++ b/actionview/lib/action_view/renderer/partial_renderer.rb
@@ -294,7 +294,7 @@ module ActionView
 
     def render(context, options, block)
       setup(context, options, block)
-      identifier = (@template = find_partial) ? @template.identifier : @path
+      @template = find_partial
 
       @lookup_context.rendered_format ||= begin
         if @template && @template.formats.present?
@@ -305,11 +305,9 @@ module ActionView
       end
 
       if @collection
-        instrument(:collection, :identifier => identifier || "collection", :count => @collection.size) do
-          render_collection
-        end
+        render_collection
       else
-        instrument(:partial, :identifier => identifier) do
+        instrument(:partial) do
           render_partial
         end
       end
@@ -318,15 +316,17 @@ module ActionView
     private
 
     def render_collection
-      return nil if @collection.blank?
+      instrument(:collection, count: @collection.size) do |payload|
+        return nil if @collection.blank?
 
-      if @options.key?(:spacer_template)
-        spacer = find_template(@options[:spacer_template], @locals.keys).render(@view, @locals)
-      end
+        if @options.key?(:spacer_template)
+          spacer = find_template(@options[:spacer_template], @locals.keys).render(@view, @locals)
+        end
 
-      cache_collection_render do
-        @template ? collection_with_template : collection_without_template
-      end.join(spacer).html_safe
+        cache_collection_render(payload) do
+          @template ? collection_with_template : collection_without_template
+        end.join(spacer).html_safe
+      end
     end
 
     def render_partial
@@ -428,8 +428,6 @@ module ActionView
         layout = find_template(layout, @template_keys)
       end
 
-      collection_cache_eligible = automatic_cache_eligible?
-
       partial_iteration = PartialIteration.new(@collection.size)
       locals[iteration] = partial_iteration
 
@@ -438,11 +436,6 @@ module ActionView
         locals[counter]   = partial_iteration.index
 
         content = template.render(view, locals)
-
-        if collection_cache_eligible
-          collection_cache_rendered_partial(content, object)
-        end
-
         content = layout.render(view, locals) { content } if layout
         partial_iteration.iterate!
         content
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 4860f00243..f7deba94ce 100644
--- a/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb
+++ b/actionview/lib/action_view/renderer/partial_renderer/collection_caching.rb
@@ -1,5 +1,3 @@
-require 'active_support/core_ext/object/try'
-
 module ActionView
   module CollectionCaching # :nodoc:
     extend ActiveSupport::Concern
@@ -11,40 +9,25 @@ module ActionView
     end
 
     private
-      def cache_collection_render
-        return yield unless cache_collection?
+      def cache_collection_render(instrumentation_payload)
+        return yield unless @options[:cached]
 
         keyed_collection = collection_by_cache_keys
-        cached_partials = collection_cache.read_multi(*keyed_collection.keys)
+        cached_partials  = collection_cache.read_multi(*keyed_collection.keys)
+        instrumentation_payload[:cache_hits] = cached_partials.size
 
         @collection = keyed_collection.reject { |key, _| cached_partials.key?(key) }.values
         rendered_partials = @collection.empty? ? [] : yield
 
         index = 0
-        keyed_collection.map do |cache_key, _|
-          cached_partials.fetch(cache_key) do
-            rendered_partials[index].tap { index += 1 }
-          end
+        fetch_or_cache_partial(cached_partials, order_by: keyed_collection.each_key) do
+          rendered_partials[index].tap { index += 1 }
         end
       end
 
-      def cache_collection?
-        @options.fetch(:cache, automatic_cache_eligible?)
-      end
-
-      def automatic_cache_eligible?
-        @template && @template.eligible_for_collection_caching?(as: @options[:as])
-      end
-
-      def callable_cache_key?
-        @options[:cache].respond_to?(:call)
-      end
-
       def collection_by_cache_keys
-        seed = callable_cache_key? ? @options[:cache] : ->(i) { i }
-
         @collection.each_with_object({}) do |item, hash|
-          hash[expanded_cache_key(seed.call(item))] = item
+          hash[expanded_cache_key(item)] = item
         end
       end
 
@@ -53,10 +36,13 @@ module ActionView
         key.frozen? ? key.dup : key # #read_multi & #write may require mutability, Dalli 2.6.0.
       end
 
-      def collection_cache_rendered_partial(rendered_partial, key_by)
-        if callable_cache_key?
-          key = expanded_cache_key(@options[:cache].call(key_by))
-          collection_cache.write(key, rendered_partial, @options[:cache_options])
+      def fetch_or_cache_partial(cached_partials, order_by:)
+        order_by.map do |cache_key|
+          cached_partials.fetch(cache_key) do
+            yield.tap do |rendered_partial|
+              collection_cache.write(cache_key, rendered_partial)
+            end
+          end
         end
       end
   end
diff --git a/actionview/lib/action_view/template.rb b/actionview/lib/action_view/template.rb
index 15fc2b71a3..169ee55fdc 100644
--- a/actionview/lib/action_view/template.rb
+++ b/actionview/lib/action_view/template.rb
@@ -130,7 +130,6 @@ module ActionView
       @source            = source
       @identifier        = identifier
       @handler           = handler
-      @cache_name        = extract_resource_cache_name
       @compiled          = false
       @original_encoding = nil
       @locals            = details[:locals] || []
@@ -166,10 +165,6 @@ module ActionView
       @type ||= Types[@formats.first] if @formats.first
     end
 
-    def eligible_for_collection_caching?(as: nil)
-      @cache_name == (as || inferred_cache_name).to_s
-    end
-
     # Receives a view object and return a template similar to self by using @virtual_path.
     #
     # This method is useful if you have a template object but it does not contain its source
@@ -355,23 +350,5 @@ module ActionView
           ActiveSupport::Notifications.instrument("#{action}.action_view".freeze, payload, &block)
         end
       end
-
-      EXPLICIT_COLLECTION = /# Template Collection: (?<resource_name>\w+)/
-
-      def extract_resource_cache_name
-        if match = @source.match(EXPLICIT_COLLECTION) || resource_cache_call_match
-          match[:resource_name]
-        end
-      end
-
-      def resource_cache_call_match
-        if @handler.respond_to?(:resource_cache_call_pattern)
-          @source.match(@handler.resource_cache_call_pattern)
-        end
-      end
-
-      def inferred_cache_name
-        @inferred_cache_name ||= @virtual_path.split('/'.freeze).last.sub('_'.freeze, ''.freeze)
-      end
   end
 end
diff --git a/actionview/lib/action_view/template/handlers/erb.rb b/actionview/lib/action_view/template/handlers/erb.rb
index 1f8459c24b..85a100ed4c 100644
--- a/actionview/lib/action_view/template/handlers/erb.rb
+++ b/actionview/lib/action_view/template/handlers/erb.rb
@@ -123,31 +123,6 @@ module ActionView
           ).src
         end
 
-        # Returns Regexp to extract a cached resource's name from a cache call at the
-        # first line of a template.
-        # The extracted cache name is captured as :resource_name.
-        #
-        #   <% cache notification do %> # => notification
-        #
-        # The pattern should support templates with a beginning comment:
-        #
-        #   <%# Still extractable even though there's a comment %>
-        #   <% cache notification do %> # => notification
-        #
-        # But fail to extract a name if a resource association is cached.
-        #
-        #   <% cache notification.event do %> # => nil
-        def resource_cache_call_pattern
-          /\A
-            (?:<%\#.*%>)*                 # optional initial comment
-            \s*                           # followed by optional spaces or newlines
-            <%\s*cache[\(\s]              # followed by an ERB call to cache
-            \s*                           # followed by optional spaces or newlines
-            (?<resource_name>\w+)         # capture the cache call argument as :resource_name
-            [\s\)]                        # followed by a space or close paren
-          /xm
-        end
-
       private
 
         def valid_encoding(string, encoding)