Is there an easy way to retrieve a pulumi stack file for something run in github actions? I'm relatively new to all this and am not sure where the stack is being persisted across github action runs. I'm in a situation where a previous run was interrupted so I need to manually fix the stack file.

Are you using the Pulumi Service backend? Have you tried

pulumi stack export

? https://www.pulumi.com/docs/reference/cli/pulumi_stack_export/