1 files changed, 30 insertions, 0 deletions
diff --git a/lib/gitlab/background_migration/user_mentions/lib/gitlab/isolated_reference_extractor.rb b/lib/gitlab/background_migration/user_mentions/lib/gitlab/isolated_reference_extractor.rb
new file mode 100644
index 00000000000..1d3a3af81a1
--- /dev/null
+++ b/lib/gitlab/background_migration/user_mentions/lib/gitlab/isolated_reference_extractor.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module BackgroundMigration
+    module UserMentions
+      module Lib
+        module Gitlab
+          # Extract possible GFM references from an arbitrary String for further processing.
+          class IsolatedReferenceExtractor < ::Gitlab::ReferenceExtractor
+            REFERABLES = %i(isolated_mentioned_group).freeze
+
+            REFERABLES.each do |type|
+              define_method("#{type}s") do
+                @references[type] ||= isolated_references(type)
+              end
+            end
+
+            def isolated_references(type)
+              context = ::Banzai::RenderContext.new(project, current_user)
+              processor = ::Gitlab::BackgroundMigration::UserMentions::Lib::Banzai::ReferenceParser[type].new(context)
+
+              refs = processor.process(html_documents)
+              refs[:visible]
+            end
+          end
+        end
+      end
+    end
+  end
+end