Use nodes and marks to power Copy-as-GFM

The spec needed to be updated because in some cases the resulting
Markdown is slightly different, though equally valid.

12 files changed, 21 insertions, 5 deletions

diff --git a/lib/banzai/filter/emoji_filter.rb b/lib/banzai/filter/emoji_filter.rb
index c87948a30bf..fa1690f73ad 100644
--- a/lib/banzai/filter/emoji_filter.rb
+++ b/lib/banzai/filter/emoji_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/emoji.js
 module Banzai
   module Filter
     # HTML filter that replaces :emoji: and unicode with images.
diff --git a/lib/banzai/filter/image_lazy_load_filter.rb b/lib/banzai/filter/image_lazy_load_filter.rb
index afaee70f351..d8b9eb29cf5 100644
--- a/lib/banzai/filter/image_lazy_load_filter.rb
+++ b/lib/banzai/filter/image_lazy_load_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/image.js
 module Banzai
   module Filter
     # HTML filter that moves the value of image `src` attributes to `data-src`
diff --git a/lib/banzai/filter/image_link_filter.rb b/lib/banzai/filter/image_link_filter.rb
index 884a94fb761..01237303c27 100644
--- a/lib/banzai/filter/image_link_filter.rb
+++ b/lib/banzai/filter/image_link_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/image.js
 module Banzai
   module Filter
     # HTML filter that wraps links around inline images.
diff --git a/lib/banzai/filter/inline_diff_filter.rb b/lib/banzai/filter/inline_diff_filter.rb
index e9ddc6e0e3d..5a1c0bee32d 100644
--- a/lib/banzai/filter/inline_diff_filter.rb
+++ b/lib/banzai/filter/inline_diff_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/marks/inline_diff.js
 module Banzai
   module Filter
     class InlineDiffFilter < HTML::Pipeline::Filter
diff --git a/lib/banzai/filter/math_filter.rb b/lib/banzai/filter/math_filter.rb
index 9d1bc3cf60c..8dd5a8979c8 100644
--- a/lib/banzai/filter/math_filter.rb
+++ b/lib/banzai/filter/math_filter.rb
@@ -2,6 +2,9 @@
 
 require 'uri'
 
+# Generated HTML is transformed back to GFM by:
+# - app/assets/javascripts/behaviors/markdown/marks/math.js
+# - app/assets/javascripts/behaviors/markdown/nodes/code_block.js
 module Banzai
   module Filter
     # HTML filter that adds class="code math" and removes the dollar sign in $`2+2`$.
diff --git a/lib/banzai/filter/mermaid_filter.rb b/lib/banzai/filter/mermaid_filter.rb
index 7c8b165a330..f0adb83af8a 100644
--- a/lib/banzai/filter/mermaid_filter.rb
+++ b/lib/banzai/filter/mermaid_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/code_block.js
 module Banzai
   module Filter
     class MermaidFilter < HTML::Pipeline::Filter
diff --git a/lib/banzai/filter/reference_filter.rb b/lib/banzai/filter/reference_filter.rb
index e5164e7f72a..42f9b3a689c 100644
--- a/lib/banzai/filter/reference_filter.rb
+++ b/lib/banzai/filter/reference_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/reference.js
 module Banzai
   module Filter
     # Base class for GitLab Flavored Markdown reference filters.
diff --git a/lib/banzai/filter/syntax_highlight_filter.rb b/lib/banzai/filter/syntax_highlight_filter.rb
index 18e5e9185de..bcf77861f10 100644
--- a/lib/banzai/filter/syntax_highlight_filter.rb
+++ b/lib/banzai/filter/syntax_highlight_filter.rb
@@ -3,6 +3,7 @@
 require 'rouge/plugins/common_mark'
 require 'rouge/plugins/redcarpet'
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/code_block.js
 module Banzai
   module Filter
     # HTML Filter to highlight fenced code blocks
diff --git a/lib/banzai/filter/table_of_contents_filter.rb b/lib/banzai/filter/table_of_contents_filter.rb
index c6d1e028eaa..f2ae17b44fa 100644
--- a/lib/banzai/filter/table_of_contents_filter.rb
+++ b/lib/banzai/filter/table_of_contents_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/table_of_contents.js
 module Banzai
   module Filter
     # HTML filter that adds an anchor child element to all Headers in a
diff --git a/lib/banzai/filter/task_list_filter.rb b/lib/banzai/filter/task_list_filter.rb
index ef35a49edcb..c6b402575cb 100644
--- a/lib/banzai/filter/task_list_filter.rb
+++ b/lib/banzai/filter/task_list_filter.rb
@@ -2,6 +2,10 @@
 
 require 'task_list/filter'
 
+# Generated HTML is transformed back to GFM by:
+# - app/assets/javascripts/behaviors/markdown/nodes/ordered_task_list.js
+# - app/assets/javascripts/behaviors/markdown/nodes/task_list.js
+# - app/assets/javascripts/behaviors/markdown/nodes/task_list_item.js
 module Banzai
   module Filter
     class TaskListFilter < TaskList::Filter
diff --git a/lib/banzai/filter/video_link_filter.rb b/lib/banzai/filter/video_link_filter.rb
index 0fb59c914c3..0fff104cf91 100644
--- a/lib/banzai/filter/video_link_filter.rb
+++ b/lib/banzai/filter/video_link_filter.rb
@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/video.js
 module Banzai
   module Filter
     # Find every image that isn't already wrapped in an `a` tag, and that has
diff --git a/lib/banzai/pipeline/gfm_pipeline.rb b/lib/banzai/pipeline/gfm_pipeline.rb
index d860dad0b6c..30cafd11834 100644
--- a/lib/banzai/pipeline/gfm_pipeline.rb
+++ b/lib/banzai/pipeline/gfm_pipeline.rb
@@ -3,11 +3,11 @@
 module Banzai
   module Pipeline
     class GfmPipeline < BasePipeline
-      # These filters convert GitLab Flavored Markdown (GFM) to HTML.
-      # The handlers defined in app/assets/javascripts/behaviors/markdown/copy_as_gfm.js
-      # consequently convert that same HTML to GFM to be copied to the clipboard.
-      # Every filter that generates HTML from GFM should have a handler in
-      # app/assets/javascripts/behaviors/markdown/copy_as_gfm.js, in reverse order.
+      # These filters transform GitLab Flavored Markdown (GFM) to HTML.
+      # The nodes and marks referenced in app/assets/javascripts/behaviors/markdown/editor_extensions.js
+      # consequently transform that same HTML to GFM to be copied to the clipboard.
+      # Every filter that generates HTML from GFM should have a node or mark in
+      # app/assets/javascripts/behaviors/markdown/editor_extensions.js.
       # The GFM-to-HTML-to-GFM cycle is tested in spec/features/copy_as_gfm_spec.rb.
       def self.filters
         @filters ||= FilterArray[