Allows handling multiple paths for efficiency

Add `members` because MR approver suggestion
needs to display non-members too.
Rename `users` to `raw_users` for clarity.

Add reader for whether code owner is defined,
which is used to decide whether to display tips.

ee/lib/gitlab/code_owners.rb

@@ -7,7 +7,7 @@ module Gitlab
 
     def self.for_blob(blob)
       if blob.project.feature_available?(:code_owners)
-        Loader.new(blob.project, blob.commit_id, blob.path).users
+        Loader.new(blob.project, blob.commit_id, blob.path).members
       else
         User.none # rubocop: disable CodeReuse/ActiveRecord
       end

ee/lib/gitlab/code_owners/loader.rb

@@ -3,17 +3,30 @@
 module Gitlab
   module CodeOwners
     class Loader
-      def initialize(project, ref, path)
-        @project, @ref, @path = project, ref, path
+      def initialize(project, ref, paths)
+        @project, @ref, @paths = project, ref, Array(paths)
       end
 
-      def users
-        return User.none if code_owners_file.empty? # rubocop: disable CodeReuse/ActiveRecord
+      def members
+        @_members ||= @project.members_among(raw_users)
+      end
+
+      def non_members
+        @_non_members ||= raw_users.where_not_in(@project.authorized_users)
+      end
+
+      def raw_users
+        return User.none if empty_code_owners? # rubocop: disable CodeReuse/ActiveRecord
 
-        owners = code_owners_file.owners_for_path(@path)
-        extracted_users = Gitlab::UserExtractor.new(owners).users
+        @_raw_users ||= begin
+          owner_lines = @paths.map { |path| code_owners_file.owners_for_path(path) }
+
+          Gitlab::UserExtractor.new(owner_lines).users
+        end
+      end
 
-        @project.authorized_users.merge(extracted_users)
+      def empty_code_owners?
+        code_owners_file.empty?
       end
 
       private

ee/spec/lib/gitlab/code_owners/loader_spec.rb

@@ -12,10 +12,12 @@ describe Gitlab::CodeOwners::Loader do
   let!(:email_owner) { create(:user, username: 'owner-2') }
   let!(:owner_3) { create(:user, username: 'owner-3') }
   let!(:documentation_owner) { create(:user, username: 'documentation-owner') }
+  let!(:test_owner) { create(:user, username: 'test-owner') }
   let(:codeowner_content) do
     <<~CODEOWNERS
     docs/* @documentation-owner
     docs/CODEOWNERS @owner-1 owner2@gitlab.org @owner-3 @documentation-owner
+    spec/* @test-owner
     CODEOWNERS
   end
   let(:codeowner_blob) { fake_blob(path: 'CODEOWNERS', data: codeowner_content) }
@@ -23,28 +25,68 @@ describe Gitlab::CodeOwners::Loader do
 
   before do
     create(:email, user: email_owner, email: 'owner2@gitlab.org')
-    project.add_developer(owner_1)
-    project.add_developer(email_owner)
-    project.add_developer(documentation_owner)
 
     allow(project.repository).to receive(:code_owners_blob).and_return(codeowner_blob)
   end
 
-  describe '#users' do
+  describe '#non_members' do
+    before do
+      project.add_developer(owner_1)
+      project.add_developer(email_owner)
+      project.add_developer(test_owner)
+    end
+
+    it 'returns all existing users that are not members of the project' do
+      expect(loader.non_members).to contain_exactly(owner_3, documentation_owner)
+    end
+
+    it 'does not return users that are members of the project' do
+      expect(loader.non_members).not_to include(owner_1, email_owner)
+    end
+
+    it 'excludes group members of the project' do
+      group.add_developer(documentation_owner)
+
+      expect(loader.non_members).to include(owner_3)
+    end
+  end
+
+  describe '#members' do
+    before do
+      project.add_developer(owner_1)
+      project.add_developer(email_owner)
+      project.add_developer(documentation_owner)
+      project.add_developer(test_owner)
+    end
+
+    it 'returns all existing users that are members of the project' do
+      expect(loader.members).to contain_exactly(owner_1, email_owner, documentation_owner)
+    end
+
+    it 'does not return users that are not members of the project' do
+      expect(loader.members).not_to include(owner_3)
+    end
+
+    it 'includes group members of the project' do
+      group.add_developer(owner_3)
+
+      expect(loader.members).to include(owner_3)
+    end
+  end
+
+  describe '#raw_users' do
     context 'with a CODEOWNERS file' do
       context 'for a path with code owners' do
-        it 'returns all existing users that are members of the project' do
-          expect(loader.users).to contain_exactly(owner_1, email_owner, documentation_owner)
-        end
-
-        it 'does not return users that are not members of the project' do
-          expect(loader.users).not_to include(owner_3)
+        it 'returns all owners' do
+          expect(loader.raw_users).to contain_exactly(owner_1, owner_3, email_owner, documentation_owner)
         end
+      end
 
-        it 'includes group members of the project' do
-          group.add_developer(owner_3)
+      context 'for multiple paths with code owners' do
+        let(:path) { ['docs/test.rb', 'spec/spec_helper.rb', 'docs/foo.rb'] }
 
-          expect(loader.users).to include(owner_3)
+        it 'returns all owners for all paths' do
+          expect(loader.raw_users).to contain_exactly(documentation_owner, test_owner)
         end
       end
 
@@ -52,7 +94,7 @@ describe Gitlab::CodeOwners::Loader do
         let(:path) { 'no-codeowner' }
 
         it 'returns no users' do
-          expect(loader.users).to be_empty
+          expect(loader.raw_users).to be_empty
         end
       end
     end
@@ -61,7 +103,7 @@ describe Gitlab::CodeOwners::Loader do
       let(:codeowner_blob) { nil }
 
       it 'returns no users without failing' do
-        expect(loader.users).to be_empty
+        expect(loader.raw_users).to be_empty
       end
     end
 
@@ -69,7 +111,7 @@ describe Gitlab::CodeOwners::Loader do
       it 'only calls out to the repository once' do
         expect(project.repository).to receive(:code_owners_blob).once
 
-        2.times { loader.users }
+        2.times { loader.raw_users }
       end
 
       it 'only processes the file once' do
@@ -77,7 +119,31 @@ describe Gitlab::CodeOwners::Loader do
 
         expect(code_owners_file).to receive(:get_parsed_data).once.and_call_original
 
-        2.times { loader.users }
+        2.times { loader.raw_users }
+      end
+    end
+  end
+
+  describe '#empty_code_owners?' do
+    context 'when file does not exist' do
+      let(:codeowner_blob) { nil }
+
+      it 'returns true' do
+        expect(loader.empty_code_owners?).to eq(true)
+      end
+    end
+
+    context 'when file is empty' do
+      let(:codeowner_content) { '' }
+
+      it 'returns true' do
+        expect(loader.empty_code_owners?).to eq(true)
+      end
+    end
+
+    context 'when file content exists' do
+      it 'returns false' do
+        expect(loader.empty_code_owners?).to eq(false)
       end
     end
   end

lib/gitlab/user_extractor.rb

@@ -11,7 +11,7 @@ module Gitlab
     USERNAME_REGEXP = User.reference_pattern
 
     def initialize(text)
-      @text = text
+      @text = text.is_a?(Array) ? text.join(' ') : text
     end
 
     # rubocop: disable CodeReuse/ActiveRecord

spec/lib/gitlab/user_extractor_spec.rb

@@ -38,6 +38,18 @@ describe Gitlab::UserExtractor do
 
       expect(extractor.users).to include(user)
     end
+
+    context 'input as array of strings' do
+      it 'is treated as one string' do
+        extractor = described_class.new(text.lines)
+
+        user_1 = create(:user, username: "USER-1")
+        user_4 = create(:user, username: "USER-4")
+        user_email = create(:user, email: 'user@gitlab.org')
+
+        expect(extractor.users).to contain_exactly(user_1, user_4, user_email)
+      end
+    end
   end
 
   describe '#matches' do