Revert change setting #format.

Author: joelhawksley

docs/CHANGELOG.md

@@ -10,6 +10,18 @@ nav_order: 6
 
 ## main
 
+* Revert change setting `#format`. In GitHub's codebase, the change led to hard-to-detect failures. For example, components rendered from controllers included layouts when they didn't before. In other cases, the response `content_type` changed, breaking downstream consumers. For cases where a specific content type is needed, use:
+
+```ruby
+respond_to do |f|
+  f.html_fragment do
+    render(MyComponent.new)
+  end
+end
+```
+
+    *Joel Hawksley*
+
 ## 4.0.0.rc4
 
 * Fix issue where generators were not included in published gem.

lib/view_component/base.rb

@@ -71,8 +71,6 @@ def config
     # Config option that strips trailing whitespace in templates before compiling them.
     class_attribute :__vc_strip_trailing_whitespace, instance_accessor: false, instance_predicate: false, default: false
 
-    class_attribute :__vc_response_format, instance_accessor: false, instance_predicate: false, default: nil
-
     attr_accessor :__vc_original_view_context
     attr_reader :current_template
 
@@ -356,10 +354,6 @@ def content?
       __vc_render_in_block_provided? || __vc_content_set_by_with_content_defined?
     end
 
-    def format
-      self.class.__vc_response_format
-    end
-
     # @private
     def with_original_virtual_path
       @view_context.instance_variable_set(:@virtual_path, @old_virtual_path)

lib/view_component/compiler.rb

@@ -48,15 +48,6 @@ def compile(raise_errors: false, force: false)
 
         define_render_template_for
 
-        # Set the format if the component only responds to a single format.
-        # Unfortunately we cannot determine which format a multi-format
-        # component will respond to until render time, so those components
-        # will not set the response format.
-        #
-        # TODO: Investigate upstream changes necessary to support multi-format renderables
-        unique_formats = templates.map(&:format).uniq
-        @component.__vc_response_format = unique_formats.last if unique_formats.one?
-
         @component.__vc_register_default_slots
         @component.__vc_build_i18n_backend
 
@@ -118,7 +109,6 @@ def template_errors
         errors << "Couldn't find a template file or inline render method for #{@component}." if @templates.empty?
 
         @templates
-          .reject { |template| template.inline_call? && !template.defined_on_self? }
           .map { |template| [template.variant, template.format] }
           .tally
           .select { |_, count| count > 1 }

lib/view_component/template.rb

@@ -43,7 +43,7 @@ class Inline < Template
       attr_reader :source
 
       def initialize(component:, inline_template:)
-        details = ActionView::TemplateDetails.new(nil, inline_template.language.to_sym, DEFAULT_FORMAT, nil)
+        details = ActionView::TemplateDetails.new(nil, inline_template.language.to_sym, nil, nil)
 
         super(
           component: component,
@@ -63,7 +63,7 @@ def type
     class InlineCall < Template
       def initialize(component:, method_name:, defined_on_self:)
         variant = method_name.to_s.include?("call_") ? method_name.to_s.sub("call_", "").to_sym : nil
-        details = ActionView::TemplateDetails.new(nil, nil, DEFAULT_FORMAT, variant)
+        details = ActionView::TemplateDetails.new(nil, nil, nil, variant)
 
         super(component: component, details: details)
 

test/sandbox/test/inline_template_test.rb

@@ -169,8 +169,4 @@ class InlineComponentDerivedFromComponentSupportingVariants < Level2Component
 
     assert_selector(".greeting-container h1", text: "Hello, Fox Mulder!")
   end
-
-  test "defines format" do
-    assert_equal(:html, InlineErbComponent.new("Tester").format)
-  end
 end

test/sandbox/test/rendering_test.rb

@@ -130,10 +130,6 @@ def test_render_without_template
     assert_selector("input[type='text'][name='name']")
   end
 
-  def test_inline_call_component_format
-    assert_equal(:html, InlineComponent.new.format)
-  end
-
   def test_render_child_without_template
     render_inline(InlineChildComponent.new)