deep_dup serialized job data instead ofattr_readonly to prevent o…

…verwriting (#363)

lib/good_job/job.rb

@@ -18,8 +18,6 @@ class Job < Object.const_get(GoodJob.active_record_parent_class)
     self.table_name = 'good_jobs'
     self.advisory_lockable_column = 'active_job_id'
 
-    attr_readonly :serialized_params
-
     # Parse a string representing a group of queues into a more readable data
     # structure.
     # @param string [String] Queue string
@@ -277,14 +275,14 @@ def executable?
 
     # @return [ExecutionResult]
     def execute
-      params = serialized_params.merge(
-        "provider_job_id" => id
-      )
-
       GoodJob::CurrentExecution.reset
       GoodJob::CurrentExecution.good_job = self
+
+      job_data = serialized_params.deep_dup
+      job_data["provider_job_id"] = id
+
       ActiveSupport::Notifications.instrument("perform_job.good_job", { good_job: self, process_id: GoodJob::CurrentExecution.process_id, thread_name: GoodJob::CurrentExecution.thread_name }) do
-        value = ActiveJob::Base.execute(params)
+        value = ActiveJob::Base.execute(job_data)
 
         if value.is_a?(Exception)
           handled_error = value

spec/lib/good_job/job_spec.rb

@@ -254,16 +254,11 @@ def perform(result_value = nil, raise_error: false)
           before do
             TestJob.retry_on(TestJob::ExpectedError, attempts: 1)
 
-            original_attr_readonly = described_class._attr_readonly
-            described_class._attr_readonly = Set.new
-
             good_job.serialized_params["exception_executions"] = { "[TestJob::ExpectedError]" => 1 }
             good_job.save!
-
-            described_class._attr_readonly = original_attr_readonly
           end
 
-          it 'does not modify the good_job serialized params' do
+          it 'does not modify the original good_job serialized params' do
             expect do
               good_job.perform
             end.not_to change { good_job.reload.serialized_params["exception_executions"]["[TestJob::ExpectedError]"] }