Error updating ResourcePolicy "projects/X/regions/us-central1/resourcePolicies/daily-backup-policy": googleapi: Error 400: Patching guest_flush field is not supported., badRequest

[runa]

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Terraform Version & Provider Version(s)

Terraform v1.9.5
on linux_amd64

• provider registry.terraform.io/hashicorp/archive v2.6.0
• provider registry.terraform.io/hashicorp/google v6.12.0
• provider registry.terraform.io/hashicorp/google-beta v6.12.0

Affected Resource(s)

google_compute_resource_policy

Terraform Configuration

Before the change:

resource "google_compute_resource_policy" "backup_policy" {
  name    = "n8n-daily-backup-policy"
  region  = var.google_region
  project = var.google_project
  snapshot_schedule_policy {
    schedule {
      daily_schedule {

        days_in_cycle = 1
        start_time    = "05:00"
      }
    }
    retention_policy {
      max_retention_days    = 30
      on_source_disk_delete = "KEEP_AUTO_SNAPSHOTS"
    }
  }
}

after the change

resource "google_compute_resource_policy" "backup_policy" {
  name    = "n8n-daily-backup-policy"
  region  = var.google_region
  project = var.google_project
  snapshot_schedule_policy {
    schedule {
      daily_schedule {

        days_in_cycle = 1
        start_time    = "05:00"
      }
    }
    snapshot_properties {
      labels = {
        app_name = "n8n"
      }
    }
    retention_policy {
      max_retention_days    = 30
      on_source_disk_delete = "KEEP_AUTO_SNAPSHOTS"
    }
  }
}

Debug Output

Encrypted with your PK and uploaded here: https://drive.google.com/file/d/1o2_aJuZ5m29FU3cgmljH-9zVvxE6QkoS/view?usp=sharing

Expected Behavior

I wanted to add a label to a snapshot

Actual Behavior

it failed:

module.n8n.google_compute_resource_policy.backup_policy: Modifying... [id=projects/retco9/regions/us-central1/resourcePolicies/n8n-daily-backup-policy]
╷
│ Error: Error updating ResourcePolicy "projects/retco9/regions/us-central1/resourcePolicies/n8n-daily-backup-policy": googleapi: Error 400: Patching guest_flush field is not supported., badRequest
│ 
│   with module.n8n.google_compute_resource_policy.backup_policy,
│   on modules/n8n/main.tf line 93, in resource "google_compute_resource_policy" "backup_policy":
│   93: resource "google_compute_resource_policy" "backup_policy" {
│ 

Steps to reproduce

1. terraform apply

Important Factoids

No response

References

No response

b/381430194

[ggtisc]

Confirmed issue!

But I can't determine if this is an enhancement or a bug, because in terraform registry there isn't any advice explaining that it is not possible to update the argument guest_flush which is auto managed, since the user is not setting any value for the guest_flush argument of the snapshot_properties block code, but in the other hand in the API documentation the guestFlush field is not listed in the available Patch methods.

I'm forwarding this issue for a deep review

[karolgorc]

The guest_flush value gets defaulted to null when the snapshot_properties block is created and then null is treated as false. The provider then takes every field in the block and sends it to the API (guest_flush included). This is seen as an attempt to patch even tough it wasn't set previously.

Basically there is no nullFields logic in place