Fix GFM reference links for closed milestones

changelogs/unreleased/bugfix_banzai_closed_milestones.yml

+---
+title: Fix GFM reference links for closed milestones
+merge_request: 15234
+author: Vitaliy @blackst0ne Klachkov
+type: fixed

lib/banzai/filter/milestone_reference_filter.rb

@@ -56,7 +56,7 @@ module Banzai
       end
 
       def find_milestone_with_finder(project, params)
-        finder_params = { project_ids: [project.id], order: nil }
+        finder_params = { project_ids: [project.id], order: nil, state: 'all' }
 
         # We don't support IID lookups for group milestones, because IIDs can
         # clash between group and project milestones.

spec/lib/banzai/filter/milestone_reference_filter_spec.rb

@@ -294,8 +294,7 @@ describe Banzai::Filter::MilestoneReferenceFilter do
     end
   end
 
-  context 'project milestones' do
-    let(:milestone) { create(:milestone, project: project) }
+  shared_context 'project milestones' do
     let(:reference) { milestone.to_reference(format: :iid) }
 
     include_examples 'reference parsing'
@@ -309,8 +308,7 @@ describe Banzai::Filter::MilestoneReferenceFilter do
     it_behaves_like 'cross project shorthand reference'
   end
 
-  context 'group milestones' do
-    let(:milestone) { create(:milestone, group: group) }
+  shared_context 'group milestones' do
     let(:reference) { milestone.to_reference(format: :name) }
 
     include_examples 'reference parsing'
@@ -354,4 +352,32 @@ describe Banzai::Filter::MilestoneReferenceFilter do
       expect(result.css('a').first.attr('href')).to eq(urls.milestone_url(milestone))
     end
   end
+
+  context 'when milestone is open' do
+    context 'project milestones' do
+      let(:milestone) { create(:milestone, project: project) }
+
+      include_context 'project milestones'
+    end
+
+    context 'group milestones' do
+      let(:milestone) { create(:milestone, group: group) }
+
+      include_context 'group milestones'
+    end
+  end
+
+  context 'when milestone is closed' do
+    context 'project milestones' do
+      let(:milestone) { create(:milestone, :closed, project: project) }
+
+      include_context 'project milestones'
+    end
+
+    context 'group milestones' do
+      let(:milestone) { create(:milestone, :closed, group: group) }
+
+      include_context 'group milestones'
+    end
+  end
 end