for cached markdown fields, select the correct engine

and also make sure that if a field is saved, then the existing cache version is maintained or only upgraded to the version with the same markdown engine.

1 files changed, 26 insertions, 4 deletions

diff --git a/app/models/concerns/cache_markdown_field.rb b/app/models/concerns/cache_markdown_field.rb
index 4ae5dd8c677..db8cf322ef7 100644
--- a/app/models/concerns/cache_markdown_field.rb
+++ b/app/models/concerns/cache_markdown_field.rb
@@ -11,7 +11,9 @@ module CacheMarkdownField
   extend ActiveSupport::Concern
 
   # Increment this number every time the renderer changes its output
-  CACHE_VERSION = 3
+  CACHE_REDCARPET_VERSION         = 3
+  CACHE_COMMONMARK_VERSION_START  = 10
+  CACHE_COMMONMARK_VERSION        = 11
 
   # changes to these attributes cause the cache to be invalidates
   INVALIDATED_BY = %w[author project].freeze
@@ -49,12 +51,14 @@ module CacheMarkdownField
 
     # Always include a project key, or Banzai complains
     project = self.project if self.respond_to?(:project)
-    group = self.group if self.respond_to?(:group)
+    group   = self.group if self.respond_to?(:group)
     context = cached_markdown_fields[field].merge(project: project, group: group)
 
     # Banzai is less strict about authors, so don't always have an author key
     context[:author] = self.author if self.respond_to?(:author)
 
+    context[:markdown_engine] = markdown_engine
+
     context
   end
 
@@ -69,7 +73,7 @@ module CacheMarkdownField
         Banzai::Renderer.cacheless_render_field(self, markdown_field, options)
       ]
     end.to_h
-    updates['cached_markdown_version'] = CacheMarkdownField::CACHE_VERSION
+    updates['cached_markdown_version'] = latest_cached_markdown_version
 
     updates.each {|html_field, data| write_attribute(html_field, data) }
   end
@@ -90,7 +94,7 @@ module CacheMarkdownField
     markdown_changed = attribute_changed?(markdown_field) || false
     html_changed = attribute_changed?(html_field) || false
 
-    CacheMarkdownField::CACHE_VERSION == cached_markdown_version &&
+    latest_cached_markdown_version == cached_markdown_version &&
       (html_changed || markdown_changed == html_changed)
   end
 
@@ -109,6 +113,24 @@ module CacheMarkdownField
     __send__(cached_markdown_fields.html_field(markdown_field)) # rubocop:disable GitlabSecurity/PublicSend
   end
 
+  def latest_cached_markdown_version
+    return CacheMarkdownField::CACHE_REDCARPET_VERSION unless cached_markdown_version
+
+    if cached_markdown_version < CacheMarkdownField::CACHE_COMMONMARK_VERSION_START
+      CacheMarkdownField::CACHE_REDCARPET_VERSION
+    else
+      CacheMarkdownField::CACHE_COMMONMARK_VERSION
+    end
+  end
+
+  def markdown_engine
+    if latest_cached_markdown_version < CacheMarkdownField::CACHE_COMMONMARK_VERSION_START
+      :redcarpet
+    else
+      :common_mark
+    end
+  end
+
   included do
     cattr_reader :cached_markdown_fields do
       FieldData.new