Document creation-only tags fields as creation-only

[rileykarson]

What kind of contribution is this issue about?

Other (specify in details)

Details

Some resources like google_folder have a tags field that's creation-only, as the API doesn't allow reading back the tags set on the resource from the resource itself. New list permissions [potentially set on the org] are required to read back the set of tags on a resource, making it infeasible to support even a simulated read-write field using the underlying tags APIs.

A sample description from https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/google_folder#tags is:

A map of resource manager tags. Resource manager tag keys and values have the same definition as resource manager tags. Keys must be in the format tagKeys/{tag_key_id}, and values are in the format tagValues/456. The field is ignored when empty. The field is immutable and causes resource replacement when mutated.

We should ensure that the fact that the fields are creation only is more clear, and recommend the dedicated tags resources for flows other than create-on-create.

References

• google_folder recreates folder when tags field is changed #19602