Add search support for protected branches API

A new `search` param is added to support searching for protected
branches by name.

This will be useful if user wants to look for a specific protected
branch but there are lots of protected branches per page.

app/finders/protected_branches_finder.rb

+# frozen_string_literal: true
+
+# ProtectedBranchesFinder
+#
+# Used to filter protected branches by set of params
+#
+# Arguments:
+#   project - which project to scope to
+#   params:
+#     search: string
+class ProtectedBranchesFinder
+  LIMIT = 100
+
+  attr_accessor :project, :params
+
+  def initialize(project, params = {})
+    @project = project
+    @params = params
+  end
+
+  def execute
+    protected_branches = project.limited_protected_branches(LIMIT)
+    protected_branches = by_name(protected_branches)
+
+    protected_branches
+  end
+
+  private
+
+  def by_name(protected_branches)
+    return protected_branches unless params[:search].present?
+
+    protected_branches.by_name(params[:search])
+  end
+end

app/models/project.rb

@@ -2303,6 +2303,10 @@ class Project < ApplicationRecord
     ci_config_path.blank? || ci_config_path == Gitlab::FileDetector::PATTERNS[:gitlab_ci]
   end
 
+  def limited_protected_branches(limit)
+    protected_branches.limit(limit)
+  end
+
   private
 
   def closest_namespace_setting(name)

app/models/protected_branch.rb

@@ -2,6 +2,7 @@
 
 class ProtectedBranch < ApplicationRecord
   include ProtectedRef
+  include Gitlab::SQL::Pattern
 
   scope :requiring_code_owner_approval,
         -> { where(code_owner_approval_required: true) }
@@ -45,6 +46,12 @@ class ProtectedBranch < ApplicationRecord
     # NOOP
     #
   end
+
+  def self.by_name(query)
+    return none if query.blank?
+
+    where(fuzzy_arel_match(:name, query.downcase))
+  end
 end
 
 ProtectedBranch.prepend_if_ee('EE::ProtectedBranch')

changelogs/unreleased/460-protected-branches-api-search.yml

+---
+title: Add search support for protected branches API
+merge_request: 24137
+author:
+type: added

lib/api/protected_branches.rb

@@ -19,10 +19,15 @@ module API
       end
       params do
         use :pagination
+        optional :search, type: String, desc: 'Search for a protected branch by name'
       end
       # rubocop: disable CodeReuse/ActiveRecord
       get ':id/protected_branches' do
-        protected_branches = user_project.protected_branches.preload(:push_access_levels, :merge_access_levels)
+        protected_branches =
+          ProtectedBranchesFinder
+            .new(user_project, params)
+            .execute
+            .preload(:push_access_levels, :merge_access_levels)
 
         present paginate(protected_branches), with: Entities::ProtectedBranch, project: user_project
       end

spec/finders/protected_branches_finder_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe ProtectedBranchesFinder do
+  let(:project) { create(:project) }
+  let!(:protected_branch) { create(:protected_branch, project: project) }
+  let!(:another_protected_branch) { create(:protected_branch, project: project) }
+  let!(:other_protected_branch) { create(:protected_branch) }
+  let(:params) { {} }
+
+  describe '#execute' do
+    subject { described_class.new(project, params).execute }
+
+    it 'returns all protected branches of project by default' do
+      expect(subject).to match_array([protected_branch, another_protected_branch])
+    end
+
+    context 'when search param is present' do
+      let(:params) { { search: protected_branch.name } }
+
+      it 'filters by search param' do
+        expect(subject).to eq([protected_branch])
+      end
+    end
+
+    context 'when there are more protected branches than the limit' do
+      before do
+        stub_const("#{described_class}::LIMIT", 1)
+      end
+
+      it 'returns limited protected branches of project' do
+        expect(subject).to eq([another_protected_branch])
+      end
+    end
+  end
+end

spec/models/project_spec.rb

@@ -5507,6 +5507,18 @@ describe Project do
     end
   end
 
+  describe '#limited_protected_branches' do
+    let(:project) { create(:project) }
+    let!(:protected_branch) { create(:protected_branch, project: project) }
+    let!(:another_protected_branch) { create(:protected_branch, project: project) }
+
+    subject { project.limited_protected_branches(1) }
+
+    it 'returns limited number of protected branches based on specified limit' do
+      expect(subject).to eq([another_protected_branch])
+    end
+  end
+
   def rugged_config
     rugged_repo(project.repository).config
   end

spec/models/protected_branch_spec.rb

@@ -220,4 +220,32 @@ describe ProtectedBranch do
       end
     end
   end
+
+  describe '.by_name' do
+    let!(:protected_branch) { create(:protected_branch, name: 'master') }
+    let!(:another_protected_branch) { create(:protected_branch, name: 'stable') }
+
+    it 'returns protected branches with a matching name' do
+      expect(described_class.by_name(protected_branch.name))
+        .to eq([protected_branch])
+    end
+
+    it 'returns protected branches with a partially matching name' do
+      expect(described_class.by_name(protected_branch.name[0..2]))
+        .to eq([protected_branch])
+    end
+
+    it 'returns protected branches with a matching name regardless of the casing' do
+      expect(described_class.by_name(protected_branch.name.upcase))
+        .to eq([protected_branch])
+    end
+
+    it 'returns nothing when nothing matches' do
+      expect(described_class.by_name('unknown')).to be_empty
+    end
+
+    it 'return nothing when query is blank' do
+      expect(described_class.by_name('')).to be_empty
+    end
+  end
 end

spec/requests/api/protected_branches_spec.rb

@@ -12,18 +12,18 @@ describe API::ProtectedBranches do
   end
 
   describe "GET /projects/:id/protected_branches" do
+    let(:params) { {} }
     let(:route) { "/projects/#{project.id}/protected_branches" }
 
     shared_examples_for 'protected branches' do
       it 'returns the protected branches' do
-        get api(route, user), params: { per_page: 100 }
+        get api(route, user), params: params.merge(per_page: 100)
 
         expect(response).to have_gitlab_http_status(200)
         expect(response).to include_pagination_headers
         expect(json_response).to be_an Array
 
         protected_branch_names = json_response.map { |x| x['name'] }
-        expected_branch_names = project.protected_branches.map { |x| x['name'] }
         expect(protected_branch_names).to match_array(expected_branch_names)
       end
     end
@@ -33,7 +33,19 @@ describe API::ProtectedBranches do
         project.add_maintainer(user)
       end
 
-      it_behaves_like 'protected branches'
+      context 'when search param is not present' do
+        it_behaves_like 'protected branches' do
+          let(:expected_branch_names) { project.protected_branches.map { |x| x['name'] } }
+        end
+      end
+
+      context 'when search param is present' do
+        it_behaves_like 'protected branches' do
+          let(:another_protected_branch) { create(:protected_branch, project: project, name: 'stable') }
+          let(:params) { { search: another_protected_branch.name } }
+          let(:expected_branch_names) { [another_protected_branch.name] }
+        end
+      end
     end
 
     context 'when authenticated as a guest' do