hashicorp/terraform · error

resource has an unsupported mode

Error message

resource %s has an unsupported mode %s

What it means

Thrown by jsonplan while computing the planned resource values (the values.go path that builds the 'resource_changes'/'planned_values' payload). The switch over r.Addr.Resource.Resource.Mode again only handles Managed and Data; ephemeral, list, invalid, or any future mode falls to default. Functionally the values-side twin of error 620.

Solutions

1. Upgrade Terraform so the planned-values serializer recognizes the resource mode.
2. Filter ephemeral/list resources out before invoking MarshalPlannedResourceChanges.
3. If extending Terraform, add the case or an explicit early skip in internal/command/jsonplan/values.go.
4. Report upstream with the address and mode string from the message.

Example fix

// before
switch r.Addr.Resource.Resource.Mode {
case addrs.ManagedResourceMode:
	resource.Mode = "managed"
case addrs.DataResourceMode:
	resource.Mode = "data"
default:
	return nil, fmt.Errorf("resource %s has an unsupported mode %s", r.Addr.String(), r.Addr.Resource.Resource.Mode.String())
}

// after (skip non-persistent modes rather than aborting)
case addrs.EphemeralResourceMode, addrs.ListResourceMode:
	continue

// Mirror of the serializer's own switch: only managed/data are JSON-encodable.
func isJSONPlannableMode(m addrs.ResourceMode) bool {
    return m == addrs.ManagedResourceMode || m == addrs.DataResourceMode
}

for _, r := range resources {
    if !isJSONPlannableMode(r.Addr.Resource.Resource.Mode) {
        continue
    }
    // ... compute planned values
}

func isPlannableResource(r *plans.ResourceChange) bool {
    switch r.Addr.Resource.Resource.Mode {
    case addrs.ManagedResourceMode, addrs.DataResourceMode:
        return true
    }
    return false
}

When it happens

Trigger: An ephemeral/list/invalid-mode resource is fed into the planned-values computation; a future ResourceMode constant is added without updating this switch; corrupted plan data with Mode==0.

Common situations: Same as 620: dev/internal builds routing unsupported modes into JSON plan serialization; cross-version plan consumption.

Related errors

• resource has an unsupported mode
• resource has an unsupported action reason
• resource has an unsupported mode
• A managed resource address is required. Importing into a…
• error reading output values

AI-assisted analysis of hashicorp/terraform@d32a084675 (2026-08-11). Data as JSON: /api/errors/fbd77361dde21a2c. Report an issue: GitHub.

Appendix: source

Thrown at internal/command/jsonplan/values.go:191

		if r.Action == plans.Delete || r.Action == plans.Forget {
			continue
		}

		resource := resource{
			Address:      r.Addr.String(),
			Type:         r.Addr.Resource.Resource.Type,
			Name:         r.Addr.Resource.Resource.Name,
			ProviderName: r.ProviderAddr.Provider.String(),
			Index:        r.Addr.Resource.Key,
		}

		switch r.Addr.Resource.Resource.Mode {
		case addrs.ManagedResourceMode:
			resource.Mode = "managed"
		case addrs.DataResourceMode:
			resource.Mode = "data"
		default:
			return nil, fmt.Errorf("resource %s has an unsupported mode %s",
				r.Addr.String(),
				r.Addr.Resource.Resource.Mode.String(),
			)
		}

		schema := schemas.ResourceTypeConfig(
			r.ProviderAddr.Provider,
			r.Addr.Resource.Resource.Mode,
			resource.Type,
		)
		if schema.Body == nil {
			return nil, fmt.Errorf("no schema found for %s", r.Addr.String())
		}
		resource.SchemaVersion = uint64(schema.Version)
		changeV, err := r.Decode(schema)
		if err != nil {
			return nil, err
		}

View on GitHub (pinned to d32a084675)