Guests can read builds if those are public

Fixes #18448

app/policies/ci/build_policy.rb

 module Ci
   class BuildPolicy < CommitStatusPolicy
     def rules
+      can! :read_build if @subject.project.public_builds?
+
       super
 
       # If we can't read build we should also not have that

app/policies/project_policy.rb

@@ -46,6 +46,11 @@ class ProjectPolicy < BasePolicy
     can! :create_note
     can! :upload_file
     can! :read_cycle_analytics
+
+    if project.public_builds?
+      can! :read_pipeline
+      can! :read_build
+    end
   end
 
   def reporter_access!

changelogs/unreleased/zj-guest-reads-public-builds.yml

+---
+title: Guests can read builds when public
+merge_request: 6842
+author: 

spec/features/projects/guest_navigation_menu_spec.rb

 require 'spec_helper'
 
 describe "Guest navigation menu" do
-  let(:project) { create :empty_project, :private }
-  let(:guest) { create :user }
+  let(:project) { create(:empty_project, :private, public_builds: false) }
+  let(:guest) { create(:user) }
 
   before do
     project.team << [guest, :guest]

spec/features/security/project/private_access_spec.rb

@@ -260,6 +260,19 @@ describe "Private Project Access", feature: true  do
     it { is_expected.to be_denied_for(:user) }
     it { is_expected.to be_denied_for(:external) }
     it { is_expected.to be_denied_for(:visitor) }
+
+    context 'when public builds is enabled' do
+      it { is_expected.to be_allowed_for guest }
+    end
+
+    context 'when public buils are disabled' do
+      before do
+        project.public_builds = false
+        project.save
+      end
+
+      it { is_expected.to be_denied_for guest }
+    end
   end
 
   describe "GET /:project_path/pipelines/:id" do
@@ -275,6 +288,19 @@ describe "Private Project Access", feature: true  do
     it { is_expected.to be_denied_for(:user) }
     it { is_expected.to be_denied_for(:external) }
     it { is_expected.to be_denied_for(:visitor) }
+
+    context 'when public builds is enabled' do
+      it { is_expected.to be_allowed_for guest }
+    end
+
+    context 'when public buils are disabled' do
+      before do
+        project.public_builds = false
+        project.save
+      end
+
+      it { is_expected.to be_denied_for guest }
+    end
   end
 
   describe "GET /:project_path/builds" do
@@ -289,6 +315,19 @@ describe "Private Project Access", feature: true  do
     it { is_expected.to be_denied_for(:user) }
     it { is_expected.to be_denied_for(:external) }
     it { is_expected.to be_denied_for(:visitor) }
+
+    context 'when public builds is enabled' do
+      it { is_expected.to be_allowed_for guest }
+    end
+
+    context 'when public buils are disabled' do
+      before do
+        project.public_builds = false
+        project.save
+      end
+
+      it { is_expected.to be_denied_for guest }
+    end
   end
 
   describe "GET /:project_path/builds/:id" do
@@ -305,6 +344,19 @@ describe "Private Project Access", feature: true  do
     it { is_expected.to be_denied_for(:user) }
     it { is_expected.to be_denied_for(:external) }
     it { is_expected.to be_denied_for(:visitor) }
+
+    context 'when public builds is enabled' do
+      it { is_expected.to be_allowed_for guest }
+    end
+
+    context 'when public buils are disabled' do
+      before do
+        project.public_builds = false
+        project.save
+      end
+
+      it { is_expected.to be_denied_for guest }
+    end
   end
 
   describe "GET /:project_path/environments" do

spec/policies/project_policy_spec.rb

@@ -111,6 +111,27 @@ describe ProjectPolicy, models: true do
     context 'guests' do
       let(:current_user) { guest }
 
+      context 'public builds enabled' do
+        let(:reporter_public_build_permissions) do
+          reporter_permissions - [:read_build, :read_pipeline]
+        end
+
+        it do
+          is_expected.to include(*guest_permissions)
+          is_expected.not_to include(*reporter_public_build_permissions)
+          is_expected.not_to include(*team_member_reporter_permissions)
+          is_expected.not_to include(*developer_permissions)
+          is_expected.not_to include(*master_permissions)
+          is_expected.not_to include(*owner_permissions)
+        end
+      end
+
+      context 'public builds disabled' do
+        before do
+          project.public_builds = false
+          project.save
+        end
+
         it do
           is_expected.to include(*guest_permissions)
           is_expected.not_to include(*reporter_permissions)
@@ -120,6 +141,7 @@ describe ProjectPolicy, models: true do
           is_expected.not_to include(*owner_permissions)
         end
       end
+    end
 
     context 'reporter' do
       let(:current_user) { reporter }

spec/requests/api/builds_spec.rb

@@ -5,7 +5,7 @@ describe API::Builds, api: true do
 
   let(:user) { create(:user) }
   let(:api_user) { user }
-  let!(:project) { create(:project, creator_id: user.id) }
+  let!(:project) { create(:project, creator_id: user.id, public_builds: false) }
   let!(:developer) { create(:project_member, :developer, user: user, project: project) }
   let(:reporter) { create(:project_member, :reporter, project: project) }
   let(:guest) { create(:project_member, :guest, project: project) }