Fix idempotency of migration on MySQL

- Add quotes to usernames in error message

Author: tcdowney

app/models/runtime/constraints/process_user_policy.rb

@@ -11,6 +11,12 @@ def validate
     return if @process.user.blank?
     return if @allowed_users.map(&:downcase).include?(@process.user.downcase)
 
-    @errors.add(:user, sprintf(ERROR_MSG, requested_user: @process.user, allowed_users: @allowed_users.join(', ')))
+    @errors.add(:user, sprintf(ERROR_MSG, requested_user: @process.user, allowed_users: formatted_users_for_error))
+  end
+
+  private
+
+  def formatted_users_for_error
+    @allowed_users.map { |u| "'#{u}'" }.join(', ')
   end
 end

db/migrations/20250610212414_add_user_to_processes.rb

@@ -1,7 +1,7 @@
 Sequel.migration do
   up do
     alter_table :processes do
-      add_column :user, String, null: true, default: nil, size: 255, if_not_exists: true
+      add_column :user, String, null: true, default: nil, size: 255 unless @db.schema(:processes).map(&:first).include?(:user)
     end
   end
 

spec/migrations/20250610212414_add_user_to_processes_spec.rb

@@ -16,7 +16,7 @@
     describe 'idempotency of up' do
       context '`user` column already exists' do
         before do
-          db.add_column :processes, :user, String, size: 255
+          db.add_column :processes, :user, String, size: 255, if_not_exists: true
         end
 
         it 'does not fail' do

spec/unit/models/runtime/constraints/process_user_policy_spec.rb

@@ -40,7 +40,7 @@
     let(:process_user) { 'vcarp' }
 
     it 'is not valid' do
-      expect(validator).to validate_with_error(process, :user, sprintf(ProcessUserPolicy::ERROR_MSG, requested_user: process.user, allowed_users: allowed_users.join(', ')))
+      expect(validator).to validate_with_error(process, :user, sprintf(ProcessUserPolicy::ERROR_MSG, requested_user: process.user, allowed_users: "'vcap', 'ContainerUser'"))
     end
   end