This isn't versioning your state though. This is using git commit history to essentially determine state at "apply-time". Versioning your state is a good idea

This isn't versioning your state though. This is using git commit history to essentially determine state at "apply-time". Versioning your state is a good idea and is already easy to do. For example if you use the S3 backend you can enable object versioning on your bucket and then everytime the state is updated it is versioning and you can rollback state that way. It is a good practice. Similarly, you could use the local state backend, which just keeps state in a json file in your project and then you could commit that json file to version control. Now git is versioning your state. But the author is not suggesting this, they are suggesting to not have a state file at all. You look at previous commits to determine state. So for example if you create a new resource for an ec2 instance in your code and run terraform apply, how does Terraform know it is new and needs to create this ec2 instance as opposed to updating an existing one? Normally it would look at the statefile and if it isn't in there, then tf knows to create it, if it is already in state then it knows to update it and reconcile the metadata in state to the declarative state in the code. But without a statefile this can't be done. So the author looks in the git history at the previous commit. If you can find the resource block in the commit history you know what it was last set to. If it doesn't exist in the history but exists in the current file, then it is presumed that the resource is new. If the resource was in the previous history but is different in the current commit then it is presumed that those changes need to be applied. I'm sure this works in simple use-cases. But at any moderate scale this could break down very quickly.