When object versioning for Google Cloud Storage (GCS) buckets is enabled, different versions of an object are stored in the bucket, preventing accidental deletion. A specific version can always be deleted when the generation number of an object version is specified in the request.
Object versioning cannot be enabled on a bucket with a retention policy. A retention policy ensures that an object is retained for a specific period of time even if a request is made to delete or replace it. Thus, a retention policy locks the single current version of an object in the bucket, which differs from object versioning where different versions of an object are retained.
== Ask Yourself Whether
* The bucket stores information that require high availability.
There is a risk if you answered yes to this question.
== Recommended Secure Coding Practices
It's recommended to enable GCS bucket versioning and thus to have the possibility to retrieve and restore different versions of an object.