Tweak code styles & doc on external approval rules

- Fix an incorrect method for update on documentation
- Utilise helper methods in API class
- Shorten long lines to improve readability

doc/api/merge_request_approvals.md

@@ -645,7 +645,7 @@ DELETE /projects/:id/external_approval_rules/:rule_id
 You can update an existing external approval rule for a project using the following endpoint:
 
 ```plaintext
-PATCH /projects/:id/external_approval_rules/:rule_id
+PUT /projects/:id/external_approval_rules/:rule_id
 ```
 
 | Attribute              | Type           | Required | Description                                        |

ee/lib/api/external_approval_rules.rb

@@ -6,32 +6,38 @@ module API
 
     feature_category :source_code_management
 
-    before { authenticate! }
-    before { user_project }
-    before { check_feature_enabled!(@project) }
+    before do
+      authenticate!
+      check_feature_enabled!
+    end
 
     helpers do
-      def check_feature_enabled!(project)
-        unauthorized! unless project.feature_available?(:compliance_approval_gates) &&
-          Feature.enabled?(:ff_compliance_approval_gates, project)
+      def check_feature_enabled!
+        unauthorized! unless user_project.feature_available?(:compliance_approval_gates) &&
+          Feature.enabled?(:ff_compliance_approval_gates, user_project)
       end
     end
 
     resource :projects, requirements: API::NAMESPACE_OR_PROJECT_REQUIREMENTS do
       segment ':id/external_approval_rules' do
-        params do
-          requires :name, type: String, desc: 'The name of the rule'
-          requires :external_url, type: String, desc: 'The URL to notify when MR receives new commits'
-          optional :protected_branch_ids, type: Array[Integer], coerce_with: ::API::Validations::Types::CommaSeparatedToIntegerArray.coerce, desc: 'The protected branch ids for this rule'
-        end
         desc 'Create a new external approval rule' do
           success ::API::Entities::ExternalApprovalRule
           detail 'This feature is gated by the :ff_compliance_approval_gates feature flag.'
         end
+        params do
+          requires :name, type: String, desc: 'The name of the external approval rule'
+          requires :external_url, type: String, desc: 'The URL to notify when MR receives new commits'
+          optional :protected_branch_ids,
+                   type: Array[Integer],
+                   coerce_with: ::API::Validations::Types::CommaSeparatedToIntegerArray.coerce,
+                   desc: 'The protected branch ids for this rule'
+        end
         post do
-          service = ::ExternalApprovalRules::CreateService.new(container: @project,
-                                                               current_user: current_user,
-                                                               params: declared(params, include_missing: false)).execute
+          service = ::ExternalApprovalRules::CreateService.new(
+            container: user_project,
+            current_user: current_user,
+            params: declared_params(include_missing: false)
+          ).execute
 
           if service.success?
             present service.payload[:rule], with: ::API::Entities::ExternalApprovalRule
@@ -47,42 +53,48 @@ module API
           use :pagination
         end
         get do
-          unauthorized! unless current_user.can?(:admin_project, @project)
+          unauthorized! unless current_user.can?(:admin_project, user_project)
 
-          present paginate(@project.external_approval_rules), with: ::API::Entities::ExternalApprovalRule
+          present paginate(user_project.external_approval_rules), with: ::API::Entities::ExternalApprovalRule
         end
+
         segment ':rule_id' do
           desc 'Delete an external approval rule' do
             detail 'This feature is gated by the :ff_compliance_approval_gates feature flag.'
           end
           params do
-            requires :rule_id, type: Integer, desc: 'The approval rule ID'
+            requires :rule_id, type: Integer, desc: 'The ID of the external approval rule'
           end
           delete do
             external_approval_rule = user_project.external_approval_rules.find(params[:rule_id])
 
             destroy_conditionally!(external_approval_rule) do |external_approval_rule|
               ::ExternalApprovalRules::DestroyService.new(
-                container: @project,
+                container: user_project,
                 current_user: current_user
               ).execute(external_approval_rule)
             end
           end
 
-          desc 'Update new external approval rule' do
+          desc 'Update an external approval rule' do
             success ::API::Entities::ExternalApprovalRule
             detail 'This feature is gated by the :ff_compliance_approval_gates feature flag.'
           end
           params do
-            requires :rule_id, type: Integer, desc: 'The approval rule ID'
-            optional :name, type: String, desc: 'The approval rule\'s name'
+            requires :rule_id, type: Integer, desc: 'The ID of the external approval rule'
+            optional :name, type: String, desc: 'The name of the approval rule'
             optional :external_url, type: String, desc: 'The URL to notify when MR receives new commits'
-            optional :protected_branch_ids, type: Array[Integer], coerce_with: ::API::Validations::Types::CommaSeparatedToIntegerArray.coerce, desc: 'The protected branch ids for this rule'
+            optional :protected_branch_ids,
+                     type: Array[Integer],
+                     coerce_with: ::API::Validations::Types::CommaSeparatedToIntegerArray.coerce,
+                     desc: 'The protected branch ids for this rule'
           end
           put do
-            service = ::ExternalApprovalRules::UpdateService.new(container: @project,
-                                                                 current_user: current_user,
-                                                                 params: declared(params, include_missing: false)).execute
+            service = ::ExternalApprovalRules::UpdateService.new(
+              container: user_project,
+              current_user: current_user,
+              params: declared_params(include_missing: false)
+            ).execute
 
             if service.success?
               present service.payload[:rule], with: ::API::Entities::ExternalApprovalRule