grafana_message_template: plan fails if template string begins or ends with an emtpy line

[moorglade]

Terraform Version

1.14.7

Terraform Grafana Provider Version

4.28.1

Grafana Version

12.4.1

Affected Resource(s)

• grafana_message_template

Terraform Configuration Files

resource "grafana_message_template" "test1" {
  name               = "test 1"
  template           = "\ntest"
}

resource "grafana_message_template" "test2" {
  name               = "test 2"
  template           = "test\n"
}

Expected Behavior

Template should be correctly provisioned in Grafana.

Actual Behavior

Terraform crashes while preparing the plan:

Planning failed. Terraform encountered an error while generating this plan.

╷
│ Error: Provider produced invalid plan
│
│ Provider "registry.terraform.io/grafana/grafana" planned an invalid value for grafana_message_template.test1.template: planned value cty.StringVal("test") does not match config value cty.StringVal("\ntest").
│
│ This is a bug in the provider, which should be reported in the provider's own issue tracker.

Steps to Reproduce

1. terraform plan

Important Factoids

No response

References

No response

[titolins]

Thanks for the report! After investigating, this isn't quite a bug in the way you might expect.

The provider intentionally trims leading/trailing whitespace from the template field (both in the plan and when reading state from the API) to avoid perpetual diffs. However, the crash you're seeing is a consequence of this normalization conflicting with a Terraform Plugin Framework constraint — a Required attribute's planned value cannot differ from the config value.

More importantly though, Grafana's API itself transforms templates that don't include a {{ define "..." }} block — it wraps the content automatically. This means a template like the example you've given gets stored as:

{{ define "test 1" }}
test
{{ end }}

Which would cause a state mismatch after apply regardless of the whitespace issue.

The correct way to define templates is to include the define block explicitly:

resource "grafana_message_template" "test1" {
  name     = "test 1"
  template = "{{ define \"test 1\" }}\ntest\n{{ end }}"
}

This matches what the API stores and what the Grafana UI expects and also allows spaces.