Add global rendering buffer

Author: BlakeWilliams

Gemfile.lock

@@ -1,78 +1,105 @@
-PATH
-  remote: .
-  specs:
-    view_component (2.48.0)
-      activesupport (>= 5.0.0, < 8.0)
-      method_source (~> 1.0)
-
-GEM
-  remote: https://rubygems.org/
+GIT
+  remote: https://github.com/rails/rails
+  revision: 532c413e8e709ab7f12997e035c166d7974e1c83
+  ref: main
   specs:
-    actioncable (7.0.1)
-      actionpack (= 7.0.1)
-      activesupport (= 7.0.1)
+    actioncable (7.1.0.alpha)
+      actionpack (= 7.1.0.alpha)
+      activesupport (= 7.1.0.alpha)
       nio4r (~> 2.0)
       websocket-driver (>= 0.6.1)
-    actionmailbox (7.0.1)
-      actionpack (= 7.0.1)
-      activejob (= 7.0.1)
-      activerecord (= 7.0.1)
-      activestorage (= 7.0.1)
-      activesupport (= 7.0.1)
+    actionmailbox (7.1.0.alpha)
+      actionpack (= 7.1.0.alpha)
+      activejob (= 7.1.0.alpha)
+      activerecord (= 7.1.0.alpha)
+      activestorage (= 7.1.0.alpha)
+      activesupport (= 7.1.0.alpha)
       mail (>= 2.7.1)
       net-imap
       net-pop
       net-smtp
-    actionmailer (7.0.1)
-      actionpack (= 7.0.1)
-      actionview (= 7.0.1)
-      activejob (= 7.0.1)
-      activesupport (= 7.0.1)
+    actionmailer (7.1.0.alpha)
+      actionpack (= 7.1.0.alpha)
+      actionview (= 7.1.0.alpha)
+      activejob (= 7.1.0.alpha)
+      activesupport (= 7.1.0.alpha)
       mail (~> 2.5, >= 2.5.4)
       net-imap
       net-pop
       net-smtp
       rails-dom-testing (~> 2.0)
-    actionpack (7.0.1)
-      actionview (= 7.0.1)
-      activesupport (= 7.0.1)
+    actionpack (7.1.0.alpha)
+      actionview (= 7.1.0.alpha)
+      activesupport (= 7.1.0.alpha)
       rack (~> 2.0, >= 2.2.0)
       rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.0, >= 1.2.0)
-    actiontext (7.0.1)
-      actionpack (= 7.0.1)
-      activerecord (= 7.0.1)
-      activestorage (= 7.0.1)
-      activesupport (= 7.0.1)
+    actiontext (7.1.0.alpha)
+      actionpack (= 7.1.0.alpha)
+      activerecord (= 7.1.0.alpha)
+      activestorage (= 7.1.0.alpha)
+      activesupport (= 7.1.0.alpha)
       globalid (>= 0.6.0)
       nokogiri (>= 1.8.5)
-    actionview (7.0.1)
-      activesupport (= 7.0.1)
+    actionview (7.1.0.alpha)
+      activesupport (= 7.1.0.alpha)
       builder (~> 3.1)
       erubi (~> 1.4)
       rails-dom-testing (~> 2.0)
       rails-html-sanitizer (~> 1.1, >= 1.2.0)
-    activejob (7.0.1)
-      activesupport (= 7.0.1)
+    activejob (7.1.0.alpha)
+      activesupport (= 7.1.0.alpha)
       globalid (>= 0.3.6)
-    activemodel (7.0.1)
-      activesupport (= 7.0.1)
-    activerecord (7.0.1)
-      activemodel (= 7.0.1)
-      activesupport (= 7.0.1)
-    activestorage (7.0.1)
-      actionpack (= 7.0.1)
-      activejob (= 7.0.1)
-      activerecord (= 7.0.1)
-      activesupport (= 7.0.1)
+    activemodel (7.1.0.alpha)
+      activesupport (= 7.1.0.alpha)
+    activerecord (7.1.0.alpha)
+      activemodel (= 7.1.0.alpha)
+      activesupport (= 7.1.0.alpha)
+    activestorage (7.1.0.alpha)
+      actionpack (= 7.1.0.alpha)
+      activejob (= 7.1.0.alpha)
+      activerecord (= 7.1.0.alpha)
+      activesupport (= 7.1.0.alpha)
       marcel (~> 1.0)
       mini_mime (>= 1.1.0)
-    activesupport (7.0.1)
+    activesupport (7.1.0.alpha)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 1.6, < 2)
       minitest (>= 5.1)
       tzinfo (~> 2.0)
+    rails (7.1.0.alpha)
+      actioncable (= 7.1.0.alpha)
+      actionmailbox (= 7.1.0.alpha)
+      actionmailer (= 7.1.0.alpha)
+      actionpack (= 7.1.0.alpha)
+      actiontext (= 7.1.0.alpha)
+      actionview (= 7.1.0.alpha)
+      activejob (= 7.1.0.alpha)
+      activemodel (= 7.1.0.alpha)
+      activerecord (= 7.1.0.alpha)
+      activestorage (= 7.1.0.alpha)
+      activesupport (= 7.1.0.alpha)
+      bundler (>= 1.15.0)
+      railties (= 7.1.0.alpha)
+    railties (7.1.0.alpha)
+      actionpack (= 7.1.0.alpha)
+      activesupport (= 7.1.0.alpha)
+      method_source
+      rake (>= 12.2)
+      thor (~> 1.0)
+      zeitwerk (~> 2.5)
+
+PATH
+  remote: .
+  specs:
+    view_component (2.49.0)
+      activesupport (>= 5.0.0, < 8.0)
+      method_source (~> 1.0)
+
+GEM
+  remote: https://rubygems.org/
+  specs:
     addressable (2.8.0)
       public_suffix (>= 2.0.2, < 5.0)
     ansi (1.5.0)
@@ -120,13 +147,13 @@ GEM
       temple (>= 0.8.0)
       tilt
     html_tokenizer (0.0.7)
-    i18n (1.8.11)
+    i18n (1.9.1)
       concurrent-ruby (~> 1.0)
     io-wait (0.2.1)
     jbuilder (2.11.5)
       actionview (>= 5.0.0)
       activesupport (>= 5.0.0)
-    loofah (2.13.0)
+    loofah (2.14.0)
       crass (~> 1.0.2)
       nokogiri (>= 1.5.9)
     mail (2.7.1)
@@ -167,32 +194,11 @@ GEM
     rack (2.2.3)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
-    rails (7.0.1)
-      actioncable (= 7.0.1)
-      actionmailbox (= 7.0.1)
-      actionmailer (= 7.0.1)
-      actionpack (= 7.0.1)
-      actiontext (= 7.0.1)
-      actionview (= 7.0.1)
-      activejob (= 7.0.1)
-      activemodel (= 7.0.1)
-      activerecord (= 7.0.1)
-      activestorage (= 7.0.1)
-      activesupport (= 7.0.1)
-      bundler (>= 1.15.0)
-      railties (= 7.0.1)
     rails-dom-testing (2.0.3)
       activesupport (>= 4.2.0)
       nokogiri (>= 1.6)
     rails-html-sanitizer (1.4.2)
       loofah (~> 2.3)
-    railties (7.0.1)
-      actionpack (= 7.0.1)
-      activesupport (= 7.0.1)
-      method_source
-      rake (>= 12.2)
-      thor (~> 1.0)
-      zeitwerk (~> 2.5)
     rainbow (3.1.1)
     rake (13.0.6)
     regexp_parser (2.2.0)
@@ -259,7 +265,7 @@ GEM
       webrick (~> 1.7.0)
     yard-activesupport-concern (0.0.1)
       yard (>= 0.8)
-    zeitwerk (2.5.3)
+    zeitwerk (2.5.4)
 
 PLATFORMS
   ruby
@@ -274,11 +280,8 @@ DEPENDENCIES
   haml (~> 5)
   jbuilder (~> 2)
   minitest (= 5.6.0)
-  net-imap
-  net-pop
-  net-smtp
   pry (~> 0.13)
-  rails (~> 7.0.0)
+  rails!
   rake (~> 13.0)
   rubocop-github (~> 0.16.1)
   simplecov (~> 0.18.0)
@@ -290,4 +293,4 @@ DEPENDENCIES
   yard-activesupport-concern
 
 BUNDLED WITH
-   2.2.33
+   2.3.7

lib/view_component.rb

@@ -11,6 +11,7 @@ module ViewComponent
   autoload :CompileCache
   autoload :ComponentError
   autoload :Deprecation
+  autoload :GlobalBuffer
   autoload :Instrumentation
   autoload :Preview
   autoload :PreviewTemplateError

lib/view_component/base.rb

@@ -69,7 +69,18 @@ def render_in(view_context, &block)
       self.class.compile(raise_errors: true)
 
       @view_context = view_context
+
+      # TODO flag with initializer
+      if !self.__vc_original_view_context
+        view_context.original_output_buffer = ActionView::OutputBuffer.new if !view_context.output_buffer
+
+        if !view_context.output_buffer.is_a?(GlobalBuffer)
+          view_context.original_output_buffer = GlobalBuffer.new(view_context.output_buffer)
+        end
+      end
+
       self.__vc_original_view_context ||= view_context
+      @output_buffer = self.__vc_original_view_context.output_buffer
 
       @lookup_context ||= view_context.lookup_context
 
@@ -104,7 +115,9 @@ def render_in(view_context, &block)
       before_render
 
       if render?
-        render_template_for(@__vc_variant).to_s + _output_postamble
+        capture do
+          render_template_for(@__vc_variant).to_s + _output_postamble
+        end
       else
         ""
       end
@@ -155,6 +168,7 @@ def initialize(*); end
     def render(options = {}, args = {}, &block)
       if options.is_a? ViewComponent::Base
         options.__vc_original_view_context = __vc_original_view_context
+        # maybe capture, but only if block given?
         super
       else
         __vc_original_view_context.render(options, args, &block)

lib/view_component/compiler.rb

@@ -69,9 +69,8 @@ def compile(raise_errors: false)
             component_class.send(:undef_method, method_name.to_sym)
           end
 
-          component_class.class_eval <<-RUBY, template[:path], -1
+          component_class.class_eval <<-RUBY, template[:path], 0
           def #{method_name}
-            @output_buffer = ActionView::OutputBuffer.new
             #{compiled_template(template[:path])}
           end
           RUBY

lib/view_component/engine.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "rails"
+require 'view_component/global_buffer'
 
 module ViewComponent
   class Engine < Rails::Engine # :nodoc:
@@ -93,6 +94,10 @@ class Engine < Rails::Engine # :nodoc:
       end
     end
 
+    initializer "view_component.global_buffer_patch" do |app|
+      ActionView::Base.include(ViewComponent::GlobalBuffer::Patch)
+    end
+
     initializer "view_component.include_render_component" do |app|
       next if Rails.version.to_f >= 6.1
 

lib/view_component/global_buffer.rb

@@ -0,0 +1,78 @@
+# frozen_string_literal: true
+
+module ViewComponent
+  # TODO if things break, log each time an unsafe string method is called
+  class GlobalBuffer
+    def initialize(buffer)
+      @_buffer = buffer
+    end
+
+    def __swap_buffer__(buffer)
+      # TODO remove once this is debugged
+      raise 'oh no' if buffer.kind_of?(GlobalBuffer)
+      @_buffer = buffer
+    end
+
+    def __buffer__
+      @_buffer
+    end
+
+    def to_s
+      @_buffer.to_s
+    end
+
+    def html_safe?
+      @_buffer.html_safe?
+    end
+
+    # Necessary for cases like `output_buffer = output_buffer.class.new(output_buffer)` (yes, this happens)
+    def class
+      @_buffer.class
+    end
+
+    def method_missing(symbol, *args, **kwargs)
+      @_buffer.send(symbol, *args, **kwargs)
+    end
+    ruby2_keywords(:method_missing) if respond_to?(:ruby2_keywords, true)
+
+    def respond_to_missing?(symbol, include_all)
+      @_buffer.respond_to?(symbol, include_all) || super
+    end
+
+    module Patch
+      extend ActiveSupport::Concern
+
+      module SeparateGlobalModuleForHAMLCompat
+        def output_buffer=(new_buf)
+          # TODO make HAML work by falling back to super
+          @output_buffer.__swap_buffer__(new_buf)
+        end
+
+        def with_output_buffer(buf = nil) # :nodoc:
+          $count ||= 0
+          $count += 1
+          unless buf
+            buf = ActionView::OutputBuffer.new
+            if output_buffer && output_buffer.respond_to?(:encoding)
+              buf.force_encoding(output_buffer.encoding)
+            end
+          end
+
+          old_buffer = output_buffer.__buffer__
+          @output_buffer.__swap_buffer__(buf)
+          yield
+          @output_buffer.__buffer__
+        ensure
+          @output_buffer.__swap_buffer__(old_buffer)
+        end
+      end
+
+      included do
+        alias_method(:original_output_buffer=, :output_buffer=)
+        prepend SeparateGlobalModuleForHAMLCompat
+
+        alias_method(:original_with_output_buffer, :with_output_buffer)
+      end
+    end
+  end
+end

test/sandbox/app/components/form_for_component.html.erb

@@ -0,0 +1,3 @@
+<%= form_for Post.new, url: "/" do |form| %>
+  <%= render LabelComponent.new(form: form) %>
+<% end %>

test/sandbox/app/components/form_for_component.rb

@@ -0,0 +1,6 @@
+# frozen_string_literal: true
+
+class FormForComponent < ViewComponent::Base
+  def initialize
+  end
+end

test/sandbox/app/components/form_with_component.html.erb

@@ -0,0 +1,3 @@
+<%= form_with model: Post.new, url: "/" do |form| %>
+  <%= render LabelComponent.new(form: form) %>
+<% end %>