hashicorp/terraform · error

expected on 1 response value, got

Error message

expected on 1 response value, got: %d

What it means

Defensive check after a successful single-op transaction. The store() closure submits exactly one KVTxnOp, so Consul must return exactly one result. If len(resp.Results) != 1, the protocol contract is violated; the message says 'expected on 1 response value' (a typo in source for 'only'). This branch is not expected to fire in practice.

Solutions

1. Capture the Terraform version, Consul version, and the full Txn response and file a bug against the consul remote-state backend.
2. Retry the operation once; a transient Consul quirk is the only realistic non-bug cause.
3. Check Consul health (`consul info`) for unusual signs.

// This branch is defensive; treat as a bug and retry once, then surface clearly.
diags := remoteClient.Put(data)
if diags.HasErrors() && strings.Contains(diags.Err().Error(), "expected on 1 response value") {
    log.Printf("consul txn returned unexpected result count; retrying once")
    diags = remoteClient.Put(data)
}
if diags.HasErrors() {
    return fmt.Errorf("unexpected consul response shape (tf=%s, consul=%s): %w", tfVersion, consulVersion, diags.Err())
}

When it happens

Trigger: store(payload) -> ok==true but len(resp.Results) != 1.

Common situations: A Consul version returning an unexpected Txn response shape; an upstream Consul API change; essentially an impossible branch. Treat any hit as a bug.

Related errors

• state already locked
• consul CAS failed with transaction errors
• Error initializing backend %T
• Error unlocking Consul state. Lock ID
• error unmarshaling lock info

AI-assisted analysis of hashicorp/terraform@d32a084675 (2026-08-11). Data as JSON: /api/errors/0911d25b8c14c024. Report an issue: GitHub.

Appendix: source

Thrown at internal/backend/remote-state/consul/client.go:251

			},
		}

		ok, resp, _, err := kv.Txn(txOps, nil)
		if err != nil {
			return err
		}
		// transaction was rolled back
		if !ok {
			var resultErr error
			for _, respError := range resp.Errors {
				resultErr = errors.Join(resultErr, errors.New(respError.What))
			}
			return fmt.Errorf("consul CAS failed with transaction errors: %w", resultErr)
		}

		if len(resp.Results) != 1 {
			// this probably shouldn't happen
			return fmt.Errorf("expected on 1 response value, got: %d", len(resp.Results))
		}

		c.modifyIndex = resp.Results[0].ModifyIndex

		// We remove all the old chunks
		cleanupOldChunks()

		return nil
	}

	if err = store(payload); err == nil {
		// The payload was small enough to be stored
		return diags
	} else if !strings.Contains(err.Error(), "too large") {
		// We failed for some other reason, report this to the user
		return diags.Append(err)
	}

View on GitHub (pinned to d32a084675)