Use monospaced font for MR diff commit link ref on GFM

changelogs/unreleased/18141-osw-use-monospaced-font-on-diffs-commit-ref.yml

+---
+title: Use monospaced font for MR diff commit link ref on GFM
+merge_request:
+author:
+type: other

lib/banzai/filter/merge_request_reference_filter.rb

@@ -25,7 +25,10 @@ module Banzai
         extras = super
 
         if commit_ref = object_link_commit_ref(object, matches)
-          return extras.unshift(commit_ref)
+          klass = reference_class(:commit, tooltip: false)
+          commit_ref_tag = %(<span class="#{klass}">#{commit_ref}</span>)
+
+          return extras.unshift(commit_ref_tag)
         end
 
         path = matches[:path] if matches.names.include?("path")

lib/banzai/filter/reference_filter.rb

@@ -65,8 +65,12 @@ module Banzai
         context[:skip_project_check]
       end
 
-      def reference_class(type)
-        "gfm gfm-#{type} has-tooltip"
+      def reference_class(type, tooltip: true)
+        gfm_klass = "gfm gfm-#{type}"
+
+        return gfm_klass unless tooltip
+
+        "#{gfm_klass} has-tooltip"
       end
 
       # Ensure that a :project key exists in context

spec/lib/banzai/filter/merge_request_reference_filter_spec.rb

@@ -210,6 +210,13 @@ describe Banzai::Filter::MergeRequestReferenceFilter do
         .to eq reference
     end
 
+    it 'commit ref tag is valid' do
+      doc = reference_filter("See #{reference}")
+      commit_ref_tag = doc.css('a').first.css('span.gfm.gfm-commit')
+
+      expect(commit_ref_tag.text).to eq(commit.short_id)
+    end
+
     it 'has valid text' do
       doc = reference_filter("See #{reference}")