hyperledger/fabric · error

failed creating a comparable principal set

Error message

failed creating a comparable principal set

What it means

Thrown by computePrincipalSets when NewComparablePrincipalSet returns nil while converting a principal set produced by a chaincode's (namespace or collection) endorsement policy via SatisfiedBy(). The policy yielded a principal the inquire package cannot represent, so discovery cannot rank peers against the endorsement policy and fails the PeersForEndorsement request.

Solutions

  1. Inspect the chaincode endorsement policy for unsupported principal types and redefine it using standard MSPRole/OU/peer principals
  2. Re-commit the chaincode (or update collection config) with a standard policy, e.g. AND('Org1MSP.peer','Org2MSP.peer')
  3. Upgrade Fabric so the inquire package supports the principal type in use
  4. Verify the policy definition tooling emits valid common.SignaturePolicyEnvelope protos

Example fix

// before
policy := "OR(ROLE('member', unknownDomain))" // malformed principal
// after
policy := "AND('Org1MSP.peer', 'Org2MSP.peer')"
Defensive patterns

Strategy: validation

Validate before calling

for _, ps := range policy.SatisfiedBy() {
  if inquire.NewComparablePrincipalSet(ps) == nil {
    return errors.New("endorsement policy contains unsupported principals")
  }
}

Type guard

func convertible(policy policies.InquireablePolicy) bool {
  for _, ps := range policy.SatisfiedBy() {
    if inquire.NewComparablePrincipalSet(ps) == nil { return false }
  }
  return true
}

Try / catch

peers, err := client.PeersForEndorsement(ctx, interest)
if err != nil && strings.Contains(err.Error(), "failed creating a comparable principal set") {
  // inspect and redefine the committed endorsement policy
}

Prevention

When it happens

Trigger: A committed chaincode endorsement policy (namespace or collection policy) contains principal types or structures that inquire.NewComparablePrincipalSet cannot convert (unsupported MSPPrincipal classification, nil/invalid principals inside the policy protobuf).

Common situations: Endorsement policies written with nonstandard principals by custom tooling; corrupted or hand-edited policy definitions; channel policies using principal categories not supported at this Fabric version.

Related errors

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/28e1ecc6c36922a2. Report an issue: GitHub.

Appendix: source

Thrown at discovery/endorsement/endorsement.go:297

				sessionLogger.Debugf("Client requested to disregard the namespace policy for chaincode %s,"+
					" and no collection policies are present", chaincode.Name)
				continue
			}
			sessionLogger.Debugf("Client requested to disregard the namespace policy for chaincode %s,"+
				" however there exist %d collection policies taken into account", chaincode.Name, len(policies)-1)
			policies = policies[1:]
		}
		inquireablePoliciesForChaincodeAndCollections = append(inquireablePoliciesForChaincodeAndCollections, policies...)
	}

	var cpss []inquire.ComparablePrincipalSets

	for _, policy := range inquireablePoliciesForChaincodeAndCollections {
		var cmpsets inquire.ComparablePrincipalSets
		for _, ps := range policy.SatisfiedBy() {
			cps := inquire.NewComparablePrincipalSet(ps)
			if cps == nil {
				return nil, errors.New("failed creating a comparable principal set")
			}
			cmpsets = append(cmpsets, cps)
		}
		if len(cmpsets) == 0 {
			return nil, errors.New("endorsement policy cannot be satisfied")
		}
		cpss = append(cpss, cmpsets)
	}

	stateBasedCPS, err := computeStateBasedPrincipalSets(interest.Chaincodes, sessionLogger)
	if err != nil {
		return nil, errors.WithStack(err)
	}

	if len(stateBasedCPS) > 0 {
		cpss = append(cpss, stateBasedCPS)
	}

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