[Elastic] Update index on push to wiki

CHANGELOG-EE

 Please view this file on the master branch, on stable branches it's out of date.
 
+v 8.6.0
+  - [Elastic] Update index on push to wiki
+
 v 8.5.0 (unreleased)
   - Show warning when mirror repository default branch could not be updated because it has diverged from upstream.
   - More reliable wiki indexer

app/workers/post_receive.rb

@@ -14,6 +14,18 @@ class PostReceive
     repo_path.gsub!(/\.git\z/, "")
     repo_path.gsub!(/\A\//, "")
 
+    if repo_path =~ /wiki\z/ && Gitlab.config.elasticsearch.enabled
+      repo_path.gsub!(/\.wiki\z/, "")
+
+      project = Project.find_with_namespace(repo_path)
+
+      if project
+        project.wiki.index_blobs
+      end
+
+      return false
+    end
+
     project = Project.find_with_namespace(repo_path)
 
     if project.nil?

spec/workers/post_receive_spec.rb

@@ -21,6 +21,16 @@ describe PostReceive do
       PostReceive.new.perform(pwd(project), key_id, base64_changes)
     end
 
+    it "triggers wiki index update" do
+      allow(Gitlab.config.elasticsearch).to receive(:enabled).and_return(true)
+      expect(Project).to receive(:find_with_namespace).with(project.path_with_namespace).and_return(project)
+      expect_any_instance_of(ProjectWiki).to receive(:index_blobs)
+
+      repo_path = "#{pwd(project)}.wiki"
+
+      PostReceive.new.perform(repo_path, key_id, base64_changes)
+    end
+
     it "does not run if the author is not in the project" do
       allow(Key).to receive(:find_by).with(hash_including(id: anything())) { nil }