Search issuables by iids

app/controllers/concerns/issuable_collections.rb

@@ -104,6 +104,12 @@ module IssuableCollections
     # Used by view to highlight active option
     @sort = options[:sort]
 
+    # When a user looks for an exact iid, we do not filter by search but only by iid
+    if params[:search] =~ /^#(?<iid>\d+)\z/
+      options[:iids] = Regexp.last_match[:iid]
+      params[:search] = nil
+    end
+
     if @project
       options[:project_id] = @project.id
       options[:attempt_project_search_optimizations] = true

changelogs/unreleased/-30974-issue-search-by-number.yml

+---
+title: "Search issuables by iids"
+merge_request: !28302
+author: Riccardo Padovani
+type: fixed

spec/controllers/concerns/issuable_collections_spec.rb

@@ -180,5 +180,16 @@ describe IssuableCollections do
         is_expected.not_to include('invalid_param', 'invalid_array')
       end
     end
+
+    context 'search using an issue iid' do
+      let(:params) { { search: "#5" } }
+
+      it 'mutates the search into a filter by iid' do
+        is_expected.to include({
+            'iids' => '5',
+            'search' => nil
+        })
+      end
+    end
   end
 end