Fix query to find the closest group integration

After propagating group-level integrations, all the inheriting
integrations have the same settings and inherit_from_id set with the id
from which they are inheriting the values.

When retrieving the default integration in order to restore the
administration settings (those coming from the group or the admin
instance), we need to look for the closest group integration which does
not inherit from its parent. Basically, the closest with
inherit_from_id = nil.

app/models/service.rb

@@ -245,7 +245,7 @@ class Service < ApplicationRecord
     group_ids = scope.ancestors.select(:id)
     array = group_ids.to_sql.present? ? "array(#{group_ids.to_sql})" : 'ARRAY[]'
 
-    where(type: type, group_id: group_ids)
+    where(type: type, group_id: group_ids, inherit_from_id: nil)
       .order(Arel.sql("array_position(#{array}::bigint[], services.group_id)"))
       .first
   end
@@ -263,7 +263,7 @@ class Service < ApplicationRecord
     from_union([
       with_templates ? active.where(template: true) : none,
       active.where(instance: true),
-      active.where(group_id: group_ids)
+      active.where(group_id: group_ids, inherit_from_id: nil)
     ]).order(Arel.sql("type ASC, array_position(#{array}::bigint[], services.group_id), instance DESC")).group_by(&:type).each do |type, records|
       build_from_integration(records.first, association => scope.id).save!
     end

spec/models/service_spec.rb

@@ -481,13 +481,21 @@ RSpec.describe Service do
             expect(described_class.default_integration('JiraService', subgroup)).to eq(group_service)
           end
 
-          context 'having a service' do
+          context 'having a service with custom settings' do
             let!(:subgroup_service) { create(:jira_service, group_id: subgroup.id, project_id: nil) }
 
             it 'returns the closest group service for a project' do
               expect(described_class.default_integration('JiraService', project)).to eq(subgroup_service)
             end
           end
+
+          context 'having a service inheriting settings' do
+            let!(:subgroup_service) { create(:jira_service, group_id: subgroup.id, project_id: nil, inherit_from_id: group_service.id) }
+
+            it 'returns the closest group service which does not inherit from its parent for a project' do
+              expect(described_class.default_integration('JiraService', project)).to eq(group_service)
+            end
+          end
         end
       end
     end