{"record":{"id":"e89f385244cbae7d","repo":"hyperledger/fabric","slug":"error-mapping-writeset","errorCode":null,"errorMessage":"error mapping WriteSet","messagePattern":"error mapping WriteSet","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"common/configtx/update.go","lineNumber":141,"sourceCode":"\t\treturn nil, err\n\t}\n\n\tif configUpdate.ChannelId != vi.channelID {\n\t\treturn nil, errors.Errorf(\"ConfigUpdate for channel '%s' but envelope for channel '%s'\", configUpdate.ChannelId, vi.channelID)\n\t}\n\n\treadSet, err := mapConfig(configUpdate.ReadSet, vi.namespace)\n\tif err != nil {\n\t\treturn nil, errors.Wrapf(err, \"error mapping ReadSet\")\n\t}\n\terr = vi.verifyReadSet(readSet)\n\tif err != nil {\n\t\treturn nil, errors.Wrapf(err, \"error validating ReadSet\")\n\t}\n\n\twriteSet, err := mapConfig(configUpdate.WriteSet, vi.namespace)\n\tif err != nil {\n\t\treturn nil, errors.Wrapf(err, \"error mapping WriteSet\")\n\t}\n\n\tdeltaSet := computeDeltaSet(readSet, writeSet)\n\tsignedData, err := protoutil.ConfigUpdateEnvelopeAsSignedData(configUpdateEnv)\n\tif err != nil {\n\t\treturn nil, err\n\t}\n\n\tif err = vi.verifyDeltaSet(deltaSet, signedData); err != nil {\n\t\treturn nil, errors.Wrapf(err, \"error validating DeltaSet\")\n\t}\n\n\tfullProposedConfig := vi.computeUpdateResult(deltaSet)\n\tif err := verifyFullProposedConfig(writeSet, fullProposedConfig); err != nil {\n\t\treturn nil, errors.Wrapf(err, \"full config did not verify\")\n\t}\n\n\treturn fullProposedConfig, nil","sourceCodeStart":123,"sourceCodeEnd":159,"githubUrl":"https://github.com/hyperledger/fabric/blob/2736b63f8fd5932511d56fe68b7039d15977f7f6/common/configtx/update.go#L123-L159","documentation":"mapConfig failed while converting the update's WriteSet into the internal comparable map, wrapping an underlying structural error (bad group path, misplaced item type, invalid key). The WriteSet could not be interpreted, so the update is rejected before policy checks.","triggerScenarios":"Calling proposeConfigUpdate/Validate with a ConfigUpdate whose WriteSet contains entries with invalid group paths or item types that mapConfig cannot map into the config namespace.","commonSituations":"Hand-crafted or corrupted write-sets; update files edited between encode/decode steps; tooling writing groups where values (or vice versa) belong; truncated updates after transfer.","solutions":["Inspect the wrapped inner error to find the offending WriteSet entry.","Regenerate the WriteSet with configtxlator by diffing the current config against the desired config.","Ensure each WriteSet entry sits in the correct ConfigUpdate field (groups, values, or policies) for its type.","Re-encode the update from valid JSON/YAML instead of patching binary protos."],"exampleFix":"// before: value placed under write_set.groups\n// after: move it to write_set.values with a proper ModPolicy set\nws.Values[\"BatchSize\"] = &cb.ConfigValue{Value: bytes, ModPolicy: \"Admins\"}","handlingStrategy":"validation","validationCode":"// Sanity-check WriteSet structure before submission\nfunc validWriteSet(update *cb.ConfigUpdate) error {\n    ws := update.GetWriteSet()\n    for g, grp := range ws.GetGroups() {\n        if g == \"\" || grp == nil { return fmt.Errorf(\"invalid group %q in write_set\", g) }\n    }\n    for k, v := range ws.GetValues() {\n        if k == \"\" || v == nil || v.GetModPolicy() == \"\" {\n            return fmt.Errorf(\"value %q missing or has no mod_policy\", k)\n        }\n    }\n    return nil\n}","typeGuard":null,"tryCatchPattern":"if _, err := validator.ProposeConfigUpdate(env, seq); err != nil {\n    if strings.Contains(err.Error(), \"error mapping WriteSet\") {\n        // fix write_set structure: correct types in correct fields, valid keys\n    }\n    return err\n}","preventionTips":["Set ModPolicy on every added/updated value and group.","Ensure items are placed in values/groups/policies fields per their type.","Generate write-sets programmatically from config diffs, not by editing binaries."],"tags":["hyperledger-fabric","configtx","writeset","malformed"],"backgroundTag":"writeset-mapping-failed","analyzedSha":"2736b63f8fd5932511d56fe68b7039d15977f7f6","analyzedAt":"2026-09-04T08:52:36.465Z","contentChangedAt":"2026-09-04T08:52:36.465Z","schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}