hashicorp/terraform · error

expected on 1 response value, got: %d

Error message

expected on 1 response value, got: %d

What it means

Internal invariant in store() (consul/client.go:251): after a single-op KV transaction succeeds, exactly one result is expected. If resp.Results has a length other than 1 it fires. Note the message itself has a typo ('expected on 1' rather than 'expected only 1'). Under the documented single-op usage this should be unreachable.

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 c9def3e214)

Solutions

1. Verify the Consul server version is compatible with the consul-api client version Terraform was built against.
2. Retry the terraform operation once; transient protocol oddities can clear.
3. Report it as a bug with consul-api / Terraform backend if it persists, since the code path assumes a single result.
4. Upgrade or downgrade Consul to a version known to honor the single-op transaction contract.

// This is an internal invariant; catch, log, and surface rather than crash
if d := client.Put(data); d.HasErrors() {
    if strings.Contains(d.Err().Error(), "expected on 1 response value") {
        log.Printf("consul transaction returned unexpected results; report upstream")
    }
    return d
}

When it happens

Trigger: len(resp.Results) != 1 after kv.Txn returned ok=true with a single KVTxnOp. Only possible if the Consul server or API client returns an unexpected number of results for a one-op transaction.

Common situations: A Consul server / consul-api version that changes transaction response shape; an exotic Consul build; effectively a programming or contract bug rather than a user error.

Related errors

• consul CAS failed with transaction errors: %w
• The remote state does not match the expected hash
• error unmarshaling lock info: %s
• state %q already locked
• failed to read state: %w

AI-assisted analysis of hashicorp/terraform@c9def3e214 (2026-08-07). Data as JSON: /api/errors/0911d25b8c14c024. Report an issue: GitHub.