Pass the template format to the digestor

This commit passes the template format to the digestor in order to come
up with a key.  Before this commit, the digestor would depend on the
side effect of the template renderer setting the rendered_format on the
lookup context.  I would like to remove that mutation, so I've changed
this to pass the template format in to the digestor.

I've introduced a new instance variable that will be alive during a
template render.  When the template is being rendered, it pushes the
current template on to a stack, setting `@current_template` to the
template currently being rendered.  When the cache helper asks the
digestor for a key, it uses the format of the template currently on the
stack.

2 files changed, 14 insertions, 13 deletions

diff --git a/actionview/test/template/digestor_test.rb b/actionview/test/template/digestor_test.rb
index ddaa7febb3..91861edf11 100644
--- a/actionview/test/template/digestor_test.rb
+++ b/actionview/test/template/digestor_test.rb
@@ -7,9 +7,8 @@ require "action_view/dependency_tracker"
 class FixtureFinder < ActionView::LookupContext
   FIXTURES_DIR = File.expand_path("../fixtures/digestor", __dir__)
 
-  def initialize(details = {})
-    super(ActionView::PathSet.new(["digestor", "digestor/api"]), details, [])
-    @rendered_format = :html
+  def self.build(details = {})
+    new(ActionView::PathSet.new(["digestor", "digestor/api"]), details, [])
   end
 end
 
@@ -146,13 +145,12 @@ class TemplateDigestorTest < ActionView::TestCase
   end
 
   def test_nested_template_deps_with_non_default_rendered_format
-    finder.rendered_format = nil
     nested_deps = [{ "comments/comments" => ["comments/comment"] }]
     assert_equal nested_deps, nested_dependencies("messages/thread")
   end
 
   def test_template_formats_of_nested_deps_with_non_default_rendered_format
-    finder.rendered_format = nil
+    @finder = finder.with_prepended_formats([:json])
     assert_equal [:json], tree_template_formats("messages/thread").uniq
   end
 
@@ -161,12 +159,10 @@ class TemplateDigestorTest < ActionView::TestCase
   end
 
   def test_template_dependencies_with_fallback_from_js_to_html_format
-    finder.rendered_format = :js
     assert_equal ["comments/comment"], dependencies("comments/show")
   end
 
   def test_template_digest_with_fallback_from_js_to_html_format
-    finder.rendered_format = :js
     assert_digest_difference("comments/show") do
       change_template("comments/_comment")
     end
@@ -219,14 +215,14 @@ class TemplateDigestorTest < ActionView::TestCase
 
   def test_details_are_included_in_cache_key
     # Cache the template digest.
-    @finder = FixtureFinder.new(formats: [:html])
+    @finder = FixtureFinder.build(formats: [:html])
     old_digest = digest("events/_event")
 
     # Change the template; the cached digest remains unchanged.
     change_template("events/_event")
 
     # The details are changed, so a new cache key is generated.
-    @finder = FixtureFinder.new
+    @finder = FixtureFinder.build
 
     # The cache is busted.
     assert_not_equal old_digest, digest("events/_event")
@@ -343,9 +339,14 @@ class TemplateDigestorTest < ActionView::TestCase
       finder_options = options.extract!(:variants, :format)
 
       finder.variants = finder_options[:variants] || []
-      finder.rendered_format = finder_options[:format] if finder_options[:format]
 
-      ActionView::Digestor.digest(name: template_name, finder: finder, dependencies: (options[:dependencies] || []))
+      finder_with_formats = if finder_options[:format]
+        finder.with_prepended_formats(Array(finder_options[:format]))
+      else
+        finder
+      end
+
+      ActionView::Digestor.digest(name: template_name, format: finder_options[:format], finder: finder_with_formats, dependencies: (options[:dependencies] || []))
     end
 
     def dependencies(template_name)
@@ -371,7 +372,7 @@ class TemplateDigestorTest < ActionView::TestCase
     end
 
     def finder
-      @finder ||= FixtureFinder.new
+      @finder ||= FixtureFinder.build
     end
 
     def change_template(template_name, variant = nil)
diff --git a/actionview/test/template/render_test.rb b/actionview/test/template/render_test.rb
index cda8c942d8..5c00596b41 100644
--- a/actionview/test/template/render_test.rb
+++ b/actionview/test/template/render_test.rb
@@ -783,7 +783,7 @@ class CachedCollectionViewRenderTest < ActiveSupport::TestCase
 
   private
     def cache_key(*names, virtual_path)
-      digest = ActionView::Digestor.digest name: virtual_path, finder: @view.lookup_context, dependencies: []
+      digest = ActionView::Digestor.digest name: virtual_path, format: :html, finder: @view.lookup_context, dependencies: []
       @view.combined_fragment_cache_key([ "#{virtual_path}:#{digest}", *names ])
     end
 end