Add OR filtering for issuable assignees

Allows OR filtering of assignees for issues and merge requests

app/finders/issuables/assignee_filter.rb

@@ -4,6 +4,7 @@ module Issuables
   class AssigneeFilter < BaseFilter
     def filter(issuables)
       filtered = by_assignee(issuables)
+      filtered = by_assignee_union(filtered)
       by_negated_assignee(filtered)
     end
 
@@ -27,6 +28,12 @@ module Issuables
       end
     end
 
+    def by_assignee_union(issuables)
+      return issuables unless or_filters_enabled? && has_assignee_param?(or_params)
+
+      issuables.assigned_to(assignee_ids(or_params))
+    end
+
     def by_negated_assignee(issuables)
       return issuables unless has_assignee_param?(not_params)
 

app/finders/issuables/author_filter.rb

@@ -21,7 +21,7 @@ module Issuables
     end
 
     def by_author_union(issuables)
-      return issuables unless or_filters_enabled? && or_params&.fetch(:author_username).present?
+      return issuables unless or_filters_enabled? && or_params&.fetch(:author_username, false).present?
 
       issuables.authored(User.by_username(or_params[:author_username]))
     end

app/models/concerns/issuable.rb

@@ -101,20 +101,19 @@ module Issuable
     scope :unassigned, -> do
       where("NOT EXISTS (SELECT TRUE FROM #{to_ability_name}_assignees WHERE #{to_ability_name}_id = #{to_ability_name}s.id)")
     end
-    scope :assigned_to, ->(u) do
-      assignees_table = Arel::Table.new("#{to_ability_name}_assignees")
-      sql = assignees_table.project('true').where(assignees_table[:user_id].in(u.id)).where(Arel::Nodes::SqlLiteral.new("#{to_ability_name}_id = #{to_ability_name}s.id"))
-      where("EXISTS (#{sql.to_sql})")
-    end
-    # rubocop:enable GitlabSecurity/SqlInjection
+    scope :assigned_to, ->(users) do
+      assignees_class = self.reflect_on_association("#{to_ability_name}_assignees").klass
 
+      condition = assignees_class.where(user_id: users).where(Arel.sql("#{to_ability_name}_id = #{to_ability_name}s.id"))
+      where(condition.arel.exists)
+    end
     scope :not_assigned_to, ->(users) do
-      assignees_table = Arel::Table.new("#{to_ability_name}_assignees")
-      sql = assignees_table.project('true')
-                .where(assignees_table[:user_id].in(users))
-                .where(Arel::Nodes::SqlLiteral.new("#{to_ability_name}_id = #{to_ability_name}s.id"))
-      where(sql.exists.not)
+      assignees_class = self.reflect_on_association("#{to_ability_name}_assignees").klass
+
+      condition = assignees_class.where(user_id: users).where(Arel.sql("#{to_ability_name}_id = #{to_ability_name}s.id"))
+      where(condition.arel.exists.not)
     end
+    # rubocop:enable GitlabSecurity/SqlInjection
 
     scope :without_particular_labels, ->(label_names) do
       labels_table = Label.arel_table

ee/spec/requests/admin/credentials_controller_spec.rb

@@ -85,6 +85,8 @@ RSpec.describe Admin::CredentialsController, type: :request do
               create(:gpg_key, user: control_user, key: GpgHelpers::User1.public_key)
               create(:gpg_key, user: control_user, key: GpgHelpers::User1.public_key2)
 
+              get admin_credentials_path(filter: 'gpg_keys')
+
               control = ActiveRecord::QueryRecorder.new(skip_cached: false) do
                 get admin_credentials_path(filter: 'gpg_keys')
               end.count

spec/finders/issues_finder_spec.rb

@@ -49,6 +49,11 @@ RSpec.describe IssuesFinder do
           let(:expected_issuables) { [issue3, issue4] }
         end
 
+        it_behaves_like 'assignee OR filter' do
+          let(:params) { { or: { assignee_id: [user.id, user2.id] } } }
+          let(:expected_issuables) { [issue1, issue2, issue3, issue5] }
+        end
+
         context 'when assignee_id does not exist' do
           it_behaves_like 'assignee NOT ID filter' do
             let(:params) { { not: { assignee_id: -100 } } }
@@ -79,6 +84,11 @@ RSpec.describe IssuesFinder do
             let(:expected_issuables) { [issue3, issue4] }
           end
 
+          it_behaves_like 'assignee OR filter' do
+            let(:params) { { or: { assignee_username: [user2.username, user3.username] } } }
+            let(:expected_issuables) { [issue2, issue3] }
+          end
+
           context 'when assignee_username does not exist' do
             it_behaves_like 'assignee NOT username filter' do
               before do

spec/support/shared_examples/finders/assignees_filter_shared_examples.rb

@@ -24,6 +24,12 @@ RSpec.shared_examples 'assignee NOT username filter' do
   end
 end
 
+RSpec.shared_examples 'assignee OR filter' do
+  it 'returns issuables assigned to the given users' do
+    expect(issuables).to contain_exactly(*expected_issuables)
+  end
+end
+
 RSpec.shared_examples 'no assignee filter' do
   let(:params) { { assignee_id: 'None' } }