hyperledger/fabric · error

Empty policy element

Error message

Empty policy element

What it means

cauthdsl.compile returns this error when the SignaturePolicy element handed to it is nil. The policy compiler cannot build an evaluatable function from a nil rule, indicating a malformed or incompletely constructed SignaturePolicyEnvelope.

Source

Thrown at common/cauthdsl/cauthdsl.go:26

import (
	"fmt"
	"time"

	"github.com/hyperledger/fabric-lib-go/common/flogging"
	cb "github.com/hyperledger/fabric-protos-go-apiv2/common"
	mb "github.com/hyperledger/fabric-protos-go-apiv2/msp"
	"github.com/hyperledger/fabric/msp"
	"go.uber.org/zap/zapcore"
)

var cauthdslLogger = flogging.MustGetLogger("cauthdsl")

// compile recursively builds a go evaluatable function corresponding to the policy specified, remember to call deduplicate on identities before
// passing them to this function for evaluation
func compile(policy *cb.SignaturePolicy, identities []*mb.MSPPrincipal) (func([]msp.Identity, []bool) bool, error) {
	if policy == nil {
		return nil, fmt.Errorf("Empty policy element")
	}

	switch t := policy.Type.(type) {
	case *cb.SignaturePolicy_NOutOf_:
		policies := make([]func([]msp.Identity, []bool) bool, len(t.NOutOf.Rules))
		for i, policy := range t.NOutOf.Rules {
			compiledPolicy, err := compile(policy, identities)
			if err != nil {
				return nil, err
			}
			policies[i] = compiledPolicy

		}
		return func(signedData []msp.Identity, used []bool) bool {
			grepKey := time.Now().UnixNano()
			cauthdslLogger.Debugf("%p gate %d evaluation starts", signedData, grepKey)
			verified := int32(0)
			_used := make([]bool, len(used))

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Regenerate the channel configuration with configtxgen instead of hand-editing.
2. Inspect the policy definition and ensure the SignaturePolicy Type (NOutOf or Rule) is set.
3. Validate the policy envelope programmatically before committing config updates.
4. If constructing policies in code, always assign policy.Type before compiling.

Example fix

// before
policy := &cb.SignaturePolicy{} // nil Type -> "Empty policy element"
// after
policy := &cb.SignaturePolicy{Type: &cb.SignaturePolicy_NOutOf_{
    NOutOf: &cb.SignaturePolicy_NOutOf{N: 1, Rules: []*cb.SignaturePolicy{...}},
}}

// pre-validate policy envelope before committing config
if pol.Policy == nil || pol.Policy.Type == nil {
    return fmt.Errorf("policy %s has empty SignaturePolicy", pol.Name)
}

func hasPolicyType(p *cb.SignaturePolicy) bool {
    return p != nil && p.Type != nil
}

_, err := compile(policy, identities)
if err != nil {
    if err.Error() == "Empty policy element" {
        log.Fatalf("malformed policy: SignaturePolicy or its Type is nil: %v", err)
    }
    return err
}

When it happens

Trigger: A channel config or policy reference resolves to a nil SignaturePolicy — e.g. hand-written config with a missing policy Type, a deserialization that left the policy unset, or programmatic policy construction omitting the rule.

Common situations: Corrupted or hand-edited channel configuration, custom tooling generating policies that leave SignaturePolicy nil, wrong policy name reference in a chaincode definition.

Related errors

• error adding policies to consortiums org group '%s'
• missing policy at path: %s
• ConfigPolicy not found at policy path: %s
• unexpected missing policy %s for item %s
• policy for %s not satisfied

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/88b6883af414b2f3. Report an issue: GitHub.