Using self.context.hook_data['some_key'] does not work when you are trying to diff a stack

I'm using the release-1.0 branch and a common workflow for me is to make edits to our template.yaml and the blueprints and then run 'stacker diff' to see the changes that would be emitted.

If you have a pre_build hook(specifically the aws_lambda.upload_lambda_functions hook) then it is impossible to diff a stack that reaches into the context.hook_data to retrieve the results(in this case the troposphere Code object being generated in the hook) because the hook_data object is not populated when you run the diff command.