dataset: reject map_fields on otel:metrics:v1 datasets

[a-khaledf]

Summary

Metrics datasets don't support map fields, but the provider happily accepted map_fields on a dataset with kind = "otel:metrics:v1" and only failed once the request hit the API. This makes it a plan-time validation error instead.

resource "axiom_dataset" "metrics" {
  name       = "metrics-ds"
  kind       = "otel:metrics:v1"
  map_fields = ["field1"]
}

Error: Invalid Attribute Combination

  with axiom_dataset.metrics,
  on main.tf line 9, in resource "axiom_dataset" "metrics":
   9:   map_fields = ["field1"]

map_fields is not supported for datasets of kind "otel:metrics:v1", remove it
from the configuration.

Implementation

The rule lives in a custom validator.List (unsupportedForKindValidator) in the map_fields Validators array, next to the existing field-name and uniqueness validators. It reads the sibling kind attribute off the config, so no resource-level ValidateConfig is needed. The predicate is factored into attributeConflictsWithKind and parameterised by kind, so the validator can be reused if another attribute/kind pair needs the same treatment.

An explicitly configured empty list (map_fields = []) is rejected as well — being set with an empty list is still configuring map fields, and this keeps Create/Update from issuing a pointless UpdateMapFields call on a metrics dataset. Omitting the attribute entirely stays valid: it remains computed/unknown, and the existing !plan.MapFields.IsUnknown() guards skip the map-fields API calls.

Other kinds are untouched, and a null/unknown kind doesn't trigger the error (null means the axiom:events:v1 default).

Testing

• TestAttributeConflictsWithKind unit tests cover set/empty/null/unknown map_fields, every other kind, and null/unknown kind.
• TestAccAxiomResources_dataset_map_fields_metrics_kind acceptance test covers both rejection cases plus metrics-without-map-fields.
• Verified against a locally built provider under dev_overrides with terraform validate (validation runs before provider configuration, so no token needed): both metrics + map_fields cases error as shown above; metrics without map_fields, and events/logs with map_fields, report Success! The configuration is valid.
• gofmt, go vet, and the unit-test suite pass. The pre-existing missing token failures in TestAccAxiomResources_basic, TestAccAxiomResources_data, and TestNotifiers are unchanged (confirmed against main).

Docs regenerated via go generate ./... for the updated map_fields description.

🤖 Generated with Claude Code