9 files changed, 27 insertions, 20 deletions
diff --git a/actionview/CHANGELOG.md b/actionview/CHANGELOG.md
index d478f4c437..122c42c5bd 100644
--- a/actionview/CHANGELOG.md
+++ b/actionview/CHANGELOG.md
@@ -1,3 +1,7 @@
+*   Add `:json` type to `auto_discovery_link_tag` to support [JSON Feeds](https://jsonfeed.org/version/1)
+
+    *Mike Gunderloy*
+
 *   Update `distance_of_time_in_words` helper to display better error messages
     for bad input.
 
diff --git a/actionview/lib/action_view/helpers/asset_tag_helper.rb b/actionview/lib/action_view/helpers/asset_tag_helper.rb
index 750f96f29e..c21fe782c6 100644
--- a/actionview/lib/action_view/helpers/asset_tag_helper.rb
+++ b/actionview/lib/action_view/helpers/asset_tag_helper.rb
@@ -122,9 +122,9 @@ module ActionView
       end
 
       # Returns a link tag that browsers and feed readers can use to auto-detect
-      # an RSS or Atom feed. The +type+ can either be <tt>:rss</tt> (default) or
-      # <tt>:atom</tt>. Control the link options in url_for format using the
-      # +url_options+. You can modify the LINK tag itself in +tag_options+.
+      # an RSS, Atom, or JSON feed. The +type+ can be <tt>:rss</tt> (default),
+      # <tt>:atom</tt>, or <tt>:json</tt>. Control the link options in url_for format
+      # using the +url_options+. You can modify the LINK tag itself in +tag_options+.
       #
       # ==== Options
       #
@@ -138,6 +138,8 @@ module ActionView
       #   # => <link rel="alternate" type="application/rss+xml" title="RSS" href="http://www.currenthost.com/controller/action" />
       #   auto_discovery_link_tag(:atom)
       #   # => <link rel="alternate" type="application/atom+xml" title="ATOM" href="http://www.currenthost.com/controller/action" />
+      #   auto_discovery_link_tag(:json)
+      #   # => <link rel="alternate" type="application/json" title="JSON" href="http://www.currenthost.com/controller/action" />
       #   auto_discovery_link_tag(:rss, {action: "feed"})
       #   # => <link rel="alternate" type="application/rss+xml" title="RSS" href="http://www.currenthost.com/controller/feed" />
       #   auto_discovery_link_tag(:rss, {action: "feed"}, {title: "My RSS"})
@@ -147,8 +149,8 @@ module ActionView
       #   auto_discovery_link_tag(:rss, "http://www.example.com/feed.rss", {title: "Example RSS"})
       #   # => <link rel="alternate" type="application/rss+xml" title="Example RSS" href="http://www.example.com/feed.rss" />
       def auto_discovery_link_tag(type = :rss, url_options = {}, tag_options = {})
-        if !(type == :rss || type == :atom) && tag_options[:type].blank?
-          raise ArgumentError.new("You should pass :type tag_option key explicitly, because you have passed #{type} type other than :rss or :atom.")
+        if !(type == :rss || type == :atom || type == :json) && tag_options[:type].blank?
+          raise ArgumentError.new("You should pass :type tag_option key explicitly, because you have passed #{type} type other than :rss, :atom, or :json.")
         end
 
         tag(
diff --git a/actionview/test/template/asset_tag_helper_test.rb b/actionview/test/template/asset_tag_helper_test.rb
index b7a993c5c9..6093a4e660 100644
--- a/actionview/test/template/asset_tag_helper_test.rb
+++ b/actionview/test/template/asset_tag_helper_test.rb
@@ -53,6 +53,7 @@ class AssetTagHelperTest < ActionView::TestCase
     %(auto_discovery_link_tag) => %(<link href="http://www.example.com" rel="alternate" title="RSS" type="application/rss+xml" />),
     %(auto_discovery_link_tag(:rss)) => %(<link href="http://www.example.com" rel="alternate" title="RSS" type="application/rss+xml" />),
     %(auto_discovery_link_tag(:atom)) => %(<link href="http://www.example.com" rel="alternate" title="ATOM" type="application/atom+xml" />),
+    %(auto_discovery_link_tag(:json)) => %(<link href="http://www.example.com" rel="alternate" title="JSON" type="application/json" />),
     %(auto_discovery_link_tag(:rss, :action => "feed")) => %(<link href="http://www.example.com" rel="alternate" title="RSS" type="application/rss+xml" />),
     %(auto_discovery_link_tag(:rss, "http://localhost/feed")) => %(<link href="http://localhost/feed" rel="alternate" title="RSS" type="application/rss+xml" />),
     %(auto_discovery_link_tag(:rss, "//localhost/feed")) => %(<link href="//localhost/feed" rel="alternate" title="RSS" type="application/rss+xml" />),
diff --git a/activerecord/lib/active_record/integration.rb b/activerecord/lib/active_record/integration.rb
index 36ce49d518..441237da1e 100644
--- a/activerecord/lib/active_record/integration.rb
+++ b/activerecord/lib/active_record/integration.rb
@@ -97,7 +97,7 @@ module ActiveRecord
     # +false+ (which it is by default until Rails 6.0).
     def cache_version
       if cache_versioning && timestamp = try(:updated_at)
-        updated_at.utc.to_s(:usec)
+        timestamp.utc.to_s(:usec)
       end
     end
 
diff --git a/activesupport/lib/active_support/cache.rb b/activesupport/lib/active_support/cache.rb
index cea603e1b3..44f80dd379 100644
--- a/activesupport/lib/active_support/cache.rb
+++ b/activesupport/lib/active_support/cache.rb
@@ -331,11 +331,7 @@ module ActiveSupport
               payload[:hit] = false if payload
               nil
             elsif entry.mismatched?(version)
-              if payload
-                payload[:hit]      = false
-                payload[:mismatch] = "#{entry.version} != #{version}"
-              end
-
+              payload[:hit] = false if payload
               nil
             else
               payload[:hit] = true if payload
diff --git a/guides/source/action_view_overview.md b/guides/source/action_view_overview.md
index c835adeab6..10412128cc 100644
--- a/guides/source/action_view_overview.md
+++ b/guides/source/action_view_overview.md
@@ -419,7 +419,7 @@ image_tag("rails.png") # => <img src="http://assets.example.com/images/rails.png
 
 #### auto_discovery_link_tag
 
-Returns a link tag that browsers and feed readers can use to auto-detect an RSS or Atom feed.
+Returns a link tag that browsers and feed readers can use to auto-detect an RSS, Atom, or JSON feed.
 
 ```ruby
 auto_discovery_link_tag(:rss, "http://www.example.com/feed.rss", { title: "RSS Feed" }) # =>
diff --git a/guides/source/layouts_and_rendering.md b/guides/source/layouts_and_rendering.md
index 48bb3147f3..caa3d21d23 100644
--- a/guides/source/layouts_and_rendering.md
+++ b/guides/source/layouts_and_rendering.md
@@ -768,7 +768,7 @@ WARNING: The asset tag helpers do _not_ verify the existence of the assets at th
 
 #### Linking to Feeds with the `auto_discovery_link_tag`
 
-The `auto_discovery_link_tag` helper builds HTML that most browsers and feed readers can use to detect the presence of RSS or Atom feeds. It takes the type of the link (`:rss` or `:atom`), a hash of options that are passed through to url_for, and a hash of options for the tag:
+The `auto_discovery_link_tag` helper builds HTML that most browsers and feed readers can use to detect the presence of RSS, Atom, or JSON feeds. It takes the type of the link (`:rss`, `:atom`, or `:json`), a hash of options that are passed through to url_for, and a hash of options for the tag:
 
 ```erb
 <%= auto_discovery_link_tag(:rss, {action: "feed"},
diff --git a/guides/source/rails_on_rack.md b/guides/source/rails_on_rack.md
index f25b185fb5..cef8450ee4 100644
--- a/guides/source/rails_on_rack.md
+++ b/guides/source/rails_on_rack.md
@@ -110,11 +110,12 @@ use ActiveSupport::Cache::Strategy::LocalCache::Middleware
 use Rack::Runtime
 use Rack::MethodOverride
 use ActionDispatch::RequestId
+use ActionDispatch::RemoteIp
+use Sprockets::Rails::QuietAssets
 use Rails::Rack::Logger
 use ActionDispatch::ShowExceptions
 use WebConsole::Middleware
 use ActionDispatch::DebugExceptions
-use ActionDispatch::RemoteIp
 use ActionDispatch::Reloader
 use ActionDispatch::Callbacks
 use ActiveRecord::Migration::CheckPending
@@ -124,7 +125,7 @@ use ActionDispatch::Flash
 use Rack::Head
 use Rack::ConditionalGet
 use Rack::ETag
-run Rails.application.routes
+run MyApp.application.routes
 ```
 
 The default middlewares shown here (and some others) are each summarized in the [Internal Middlewares](#internal-middleware-stack) section, below.
@@ -238,6 +239,14 @@ Much of Action Controller's functionality is implemented as Middlewares. The fol
 
 * Makes a unique `X-Request-Id` header available to the response and enables the `ActionDispatch::Request#request_id` method.
 
+**`ActionDispatch::RemoteIp`**
+
+* Checks for IP spoofing attacks.
+
+**`Sprockets::Rails::QuietAssets`**
+
+* Suppresses logger output for asset requests.
+
 **`Rails::Rack::Logger`**
 
 * Notifies the logs that the request has began. After request is complete, flushes all the logs.
@@ -250,10 +259,6 @@ Much of Action Controller's functionality is implemented as Middlewares. The fol
 
 * Responsible for logging exceptions and showing a debugging page in case the request is local.
 
-**`ActionDispatch::RemoteIp`**
-
-* Checks for IP spoofing attacks.
-
 **`ActionDispatch::Reloader`**
 
 * Provides prepare and cleanup callbacks, intended to assist with code reloading during development.
diff --git a/railties/lib/rails/generators/rails/app/app_generator.rb b/railties/lib/rails/generators/rails/app/app_generator.rb
index b7bf45c522..4af84885bc 100644
--- a/railties/lib/rails/generators/rails/app/app_generator.rb
+++ b/railties/lib/rails/generators/rails/app/app_generator.rb
@@ -121,7 +121,6 @@ module Rails
       action_cable_config_exist = File.exist?("config/cable.yml")
       rack_cors_config_exist = File.exist?("config/initializers/cors.rb")
       assets_config_exist = File.exist?("config/initializers/assets.rb")
-      new_framework_defaults_5_2_exist = File.exist?("config/initializers/new_framework_defaults_5_2.rb")
 
       config