{"record":{"id":"395b2011155c921a","repo":"hyperledger/fabric","slug":"delta-set-was-empty-update-would-have-no-effect","errorCode":null,"errorMessage":"delta set was empty -- update would have no effect","messagePattern":"delta set was empty -- update would have no effect","errorType":"validation","errorClass":null,"httpStatus":null,"severity":"error","filePath":"common/configtx/update.go","lineNumber":70,"sourceCode":"\t}\n\n\ttrimmed := modPolicy\n\tif modPolicy[0] == '/' {\n\t\ttrimmed = modPolicy[1:]\n\t}\n\n\tfor i, pathElement := range strings.Split(trimmed, pathSeparator) {\n\t\terr := validateConfigID(pathElement)\n\t\tif err != nil {\n\t\t\treturn errors.Wrapf(err, \"path element at %d is invalid\", i)\n\t\t}\n\t}\n\treturn nil\n}\n\nfunc (vi *ValidatorImpl) verifyDeltaSet(deltaSet map[string]comparable, signedData []*protoutil.SignedData) error {\n\tif len(deltaSet) == 0 {\n\t\treturn errors.Errorf(\"delta set was empty -- update would have no effect\")\n\t}\n\n\tfor key, value := range deltaSet {\n\t\tlogger.Debugf(\"Processing change to key: %s\", key)\n\t\tif err := validateModPolicy(value.modPolicy()); err != nil {\n\t\t\treturn errors.Wrapf(err, \"invalid mod_policy for element %s\", key)\n\t\t}\n\n\t\texisting, ok := vi.configMap[key]\n\t\tif !ok {\n\t\t\tif value.version() != 0 {\n\t\t\t\treturn errors.Errorf(\"attempted to set key %s to version %d, but key does not exist\", key, value.version())\n\t\t\t}\n\n\t\t\tcontinue\n\t\t}\n\t\tif value.version() != existing.version()+1 {\n\t\t\treturn errors.Errorf(\"attempt to set key %s to version %d, but key is at version %d\", key, value.version(), existing.version())","sourceCodeStart":52,"sourceCodeEnd":88,"githubUrl":"https://github.com/hyperledger/fabric/blob/2736b63f8fd5932511d56fe68b7039d15977f7f6/common/configtx/update.go#L52-L88","documentation":"Returned by verifyDeltaSet when the computed set of changes between two configs is empty. An authorized config update must modify at least one element; an empty delta means the proposed update is a no-op and is rejected before signature/policy checks.","triggerScenarios":"Calling authorizeUpdate with a ConfigUpdate whose write set equals its read set, so computeDeltaSet yields an empty map.","commonSituations":"Submitting an update envelope that re-uploads the identical config; a client bug that doesn't apply intended changes before computing the write set.","solutions":["Ensure the write set actually differs from the read set (apply your intended change to the config).","Check that the client code copies/mutates the config rather than resubmitting the original unchanged value.","Skip submitting the update entirely if no changes are intended."],"exampleFix":"// before\nnewConfig := proto.Clone(currentConfig).(*cb.Config) // unchanged, empty delta\n// after\nnewConfig.ChannelGroup.Groups[\"Org4\"] = newOrgGroup // actually add the change","handlingStrategy":"validation","validationCode":"delta := computeDeltaSet(readSet, writeSet)\nif len(delta) == 0 {\n  return errors.New(\"update has no effect; skipping submission\")\n}","typeGuard":"func hasEffectiveChange(readSet, writeSet map[string]comparable) bool { return len(computeDeltaSet(readSet, writeSet)) > 0 }","tryCatchPattern":"err := validator.ProposeUpdate(env)\nif err != nil && strings.Contains(err.Error(), \"delta set was empty\") {\n  return nil // no-op update; skip instead of resubmitting\n}","preventionTips":["Compute and inspect the delta set before submitting","Verify client code actually mutates the config before generating the write set","Treat identical-config submissions as no-ops and short-circuit"],"tags":["hyperledger-fabric","configtx","channel-update"],"backgroundTag":"empty-config-delta","analyzedSha":"2736b63f8fd5932511d56fe68b7039d15977f7f6","analyzedAt":"2026-09-04T08:52:36.465Z","contentChangedAt":"2026-09-04T08:52:36.465Z","schemaVersion":2},"datasetVersion":"2026-09-08T15:18:49.778Z"}