hyperledger/fabric · error

nil policy field

Error message

nil policy field

What it means

policy.Convert returns the stored *cb.SignaturePolicyEnvelope; policies created without one (signaturePolicyEnvelope left nil) cannot be converted, so this error is returned. Only used by consumers that need the original envelope back from a compiled policy.

Source

Thrown at common/cauthdsl/policy.go:112

}

// EvaluateIdentities takes an array of identities and evaluates whether
// they satisfy the policy
func (p *policy) EvaluateIdentities(identities []msp.Identity) error {
	if p == nil {
		return fmt.Errorf("No such policy")
	}

	ok := p.evaluator(identities, make([]bool, len(identities)))
	if !ok {
		return errors.New("signature set did not satisfy policy")
	}
	return nil
}

func (p *policy) Convert() (*cb.SignaturePolicyEnvelope, error) {
	if p.signaturePolicyEnvelope == nil {
		return nil, errors.New("nil policy field")
	}

	return p.signaturePolicyEnvelope, nil
}

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Only call Convert on policies created with their envelope attached, or nil-check inside the caller
2. Construct the policy via the path that stores signaturePolicyEnvelope
3. Return the envelope at policy-creation time instead of converting later

Example fix

// before
env, err := p.Convert() // p.signaturePolicyEnvelope == nil
// after
if p.signaturePolicyEnvelope == nil {
    return nil, errors.New("policy has no envelope; reconstruct it from the rule")
}
env, err := p.Convert()

if p == nil || p.signaturePolicyEnvelope == nil {
    return nil, errors.New("policy carries no envelope to convert")
}

func convertible(p *policy) bool { return p != nil && p.signaturePolicyEnvelope != nil }

env, err := p.Convert()
if err != nil {
    if err.Error() == "nil policy field" {
        return nil, errors.New("this policy was constructed without an envelope")
    }
    return nil, err
}

When it happens

Trigger: Calling (*policy).Convert on a policy whose signaturePolicyEnvelope field was never populated — i.e. the policy was built through a path that stores only the compiled evaluator (as in TestConverter).

Common situations: Framework code that round-trips policies to inspect or rewrite their envelopes encountering a policy constructed programmatically from an already-compiled closure.

Related errors

• no such policy
• No such policy
• error converting policy with reference '%s' on channel '%s'
• Invalid signed proposal during channelless check policy with
• Empty policy element

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/4b7c0508fe9539e1. Report an issue: GitHub.