Add autocomplete search suggestions for recent merge requests

This implements the same behaviour for merge requests that was added
for issues in
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/40669.

app/controllers/projects/merge_requests_controller.rb

@@ -50,6 +50,8 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
   around_action :allow_gitaly_ref_name_caching, only: [:index, :show, :discussions]
+  after_action :log_merge_request_show, only: [:show]
+
   feature_category :source_code_management,
                    unless: -> (action) { action.ends_with?("_reports") }
   feature_category :code_testing,
@@ -450,6 +452,12 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
     end
   end
+  def log_merge_request_show
+    return unless current_user && @merge_request
+
+    ::Gitlab::Search::RecentMergeRequests.new(user: current_user).log_view(@merge_request)
+  end
+
   def authorize_read_actual_head_pipeline!
     return render_404 unless can?(current_user, :read_build, merge_request.actual_head_pipeline)
   end

app/helpers/search_helper.rb

@@ -7,6 +7,7 @@ module SearchHelper
     return unless current_user
     resources_results = [
+      recent_merge_requests_autocomplete(term),
       recent_issues_autocomplete(term),
       groups_autocomplete(term),
       projects_autocomplete(term)
@@ -180,6 +181,20 @@ module SearchHelper
     end
   end
+  def recent_merge_requests_autocomplete(term, limit = 5)
+    return [] unless current_user
+
+    ::Gitlab::Search::RecentMergeRequests.new(user: current_user).search(term).limit(limit).map do |mr|
+      {
+        category: "Recent merge requests",
+        id: mr.id,
+        label: search_result_sanitize(mr.title),
+        url: merge_request_path(mr),
+        avatar_url: mr.project.avatar_url || ''
+      }
+    end
+  end
+
   def recent_issues_autocomplete(term, limit = 5)
     return [] unless current_user

app/models/merge_request.rb

@@ -21,6 +21,7 @@ class MergeRequest < ApplicationRecord
   include MilestoneEventable
   include StateEventable
   include ApprovableBase
+  include IdInOrdered
   extend ::Gitlab::Utils::Override

changelogs/unreleased/249091-autocomplete-recent-mrs.yml

+---
+title: Add autocomplete search suggestions for recent merge requests
+merge_request: 42560
+author:
+type: added

doc/user/search/index.md

@@ -171,6 +171,7 @@ You can also type in this search bar to see autocomplete suggestions for:
 - Project feature pages (try and type **milestones**)
 - Various settings pages (try and type **user settings**)
 - Recently viewed issues (try and type some word from the title of a recently viewed issue)
+- Recently viewed merge requests (try and type some word from the title of a recently merge request)
 ## To-Do List

lib/gitlab/search/recent_merge_requests.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Search
+    class RecentMergeRequests < RecentItems
+      private
+
+      def type
+        MergeRequest
+      end
+
+      def finder
+        MergeRequestsFinder
+      end
+    end
+  end
+end

spec/controllers/projects/issues_controller_spec.rb

@@ -1029,7 +1029,8 @@ RSpec.describe Projects::IssuesController do
         go(id: issue.to_param)
-        expect(recent_issues_double).to have_received(:log_view)
+        expect(response).to be_successful
+        expect(recent_issues_double).to have_received(:log_view).with(issue)
       end
       context 'when not logged in' do

spec/controllers/projects/merge_requests_controller_spec.rb

@@ -123,6 +123,16 @@ RSpec.describe Projects::MergeRequestsController do
         expect(response).to be_successful
       end
+      it 'logs the view with Gitlab::Search::RecentMergeRequests' do
+        recent_merge_requests_double = instance_double(::Gitlab::Search::RecentMergeRequests, log_view: nil)
+        expect(::Gitlab::Search::RecentMergeRequests).to receive(:new).with(user: user).and_return(recent_merge_requests_double)
+
+        go(format: :html)
+
+        expect(response).to be_successful
+        expect(recent_merge_requests_double).to have_received(:log_view).with(merge_request)
+      end
+
       context "that is invalid" do
         let(:merge_request) { create(:invalid_merge_request, target_project: project, source_project: project) }

spec/helpers/search_helper_spec.rb

@@ -106,6 +106,39 @@ RSpec.describe SearchHelper do
         })
       end
+      it 'includes the first 5 of the users recent merge requests' do
+        recent_merge_requests = instance_double(::Gitlab::Search::RecentMergeRequests)
+        expect(::Gitlab::Search::RecentMergeRequests).to receive(:new).with(user: user).and_return(recent_merge_requests)
+        project1 = create(:project, :with_avatar, namespace: user.namespace)
+        project2 = create(:project, namespace: user.namespace)
+        merge_request1 = create(:merge_request, :unique_branches, title: 'Merge request 1', target_project: project1, source_project: project1)
+        merge_request2 = create(:merge_request, :unique_branches, title: 'Merge request 2', target_project: project2, source_project: project2)
+
+        other_merge_requests = create_list(:merge_request, 5)
+
+        expect(recent_merge_requests).to receive(:search).with('the search term').and_return(MergeRequest.id_in_ordered([merge_request1.id, merge_request2.id, *other_merge_requests.map(&:id)]))
+
+        results = search_autocomplete_opts("the search term")
+
+        expect(results.count).to eq(5)
+
+        expect(results[0]).to include({
+          category: 'Recent merge requests',
+          id: merge_request1.id,
+          label: 'Merge request 1',
+          url: Gitlab::Routing.url_helpers.project_merge_request_path(merge_request1.project, merge_request1),
+          avatar_url: project1.avatar_url
+        })
+
+        expect(results[1]).to include({
+          category: 'Recent merge requests',
+          id: merge_request2.id,
+          label: 'Merge request 2',
+          url: Gitlab::Routing.url_helpers.project_merge_request_path(merge_request2.project, merge_request2),
+          avatar_url: '' # This project didn't have an avatar so set this to ''
+        })
+      end
+
       it "does not include the public group" do
         group = create(:group)
         expect(search_autocomplete_opts(group.name).size).to eq(0)

spec/lib/gitlab/search/recent_merge_requests_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe ::Gitlab::Search::RecentMergeRequests do
+  def create_item(content:, project:)
+    create(:merge_request, :unique_branches, title: content, target_project: project, source_project: project)
+  end
+
+  it_behaves_like 'search recent items'
+end