Fix error when blob has no auxiliary viewer

app/helpers/blob_helper.rb

@@ -359,7 +359,7 @@ module BlobHelper
   def show_suggest_pipeline_creation_celebration?
     experiment_enabled?(:suggest_pipeline) &&
       @blob.path == Gitlab::FileDetector::PATTERNS[:gitlab_ci] &&
-      @blob.auxiliary_viewer.valid?(project: @project, sha: @commit.sha, user: current_user) &&
+      @blob.auxiliary_viewer&.valid?(project: @project, sha: @commit.sha, user: current_user) &&
       @project.uses_default_ci_config? &&
       cookies[suggest_pipeline_commit_cookie_name].present?
   end

changelogs/unreleased/weimeng-master-patch-35379.yml

+---
+title: Fix error when blob has no auxiliary viewer
+merge_request: 38018
+author:
+type: fixed

spec/helpers/blob_helper_spec.rb

@@ -282,6 +282,16 @@ RSpec.describe BlobHelper do
               expect(helper.show_suggest_pipeline_creation_celebration?).to be_falsey
             end
           end
+
+          context 'blob does not have auxiliary view' do
+            before do
+              allow(blob).to receive(:auxiliary_viewer).and_return(nil)
+            end
+
+            it 'is false' do
+              expect(helper.show_suggest_pipeline_creation_celebration?).to be_falsey
+            end
+          end
         end
 
         context 'experiment disabled' do