{"record":{"id":"4fb2d701845bd21d","repo":"chenhg5/cc-connect","slug":"encode-rpc-message-w","errorCode":null,"errorMessage":"encode rpc message: %w","messagePattern":"encode rpc message: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"agent/codex/session.go","lineNumber":779,"sourceCode":"\t\t\t}\n\t\t}\n\t\treturn nil\n\t}\n}\n\nfunc rpcNotifyOverIO(stdin io.Writer, method string, params any) error {\n\tpayload := map[string]any{\n\t\t\"jsonrpc\": \"2.0\",\n\t\t\"method\":  method,\n\t\t\"params\":  params,\n\t}\n\treturn writeRPCMessage(stdin, payload)\n}\n\nfunc writeRPCMessage(w io.Writer, payload any) error {\n\tb, err := json.Marshal(payload)\n\tif err != nil {\n\t\treturn fmt.Errorf(\"encode rpc message: %w\", err)\n\t}\n\tif _, err := w.Write(append(b, '\\n')); err != nil {\n\t\treturn fmt.Errorf(\"write rpc message: %w\", err)\n\t}\n\treturn nil\n}\n\n// RespondPermission is a no-op for Codex — permissions are handled via CLI flags.\nfunc (cs *codexSession) RespondPermission(_ string, _ core.PermissionResult) error {\n\treturn nil\n}\n\nfunc (cs *codexSession) Events() <-chan core.Event {\n\treturn cs.events\n}\n\nfunc (cs *codexSession) CurrentSessionID() string {\n\tv, _ := cs.threadID.Load().(string)","sourceCodeStart":761,"sourceCodeEnd":797,"githubUrl":"https://github.com/chenhg5/cc-connect/blob/4000b2338aa6e850c99df54f8b0ed6ed7460b401/agent/codex/session.go#L761-L797","documentation":"writeRPCMessage marshals an outgoing JSON-RPC payload (params or notification) with encoding/json and failed, returning a wrapped \"encode rpc message\" error. Marshal only fails for values the JSON encoder cannot represent (channels, funcs, cyclic structures, or invalid types like NaN in float fields), so this points to a bad payload constructed before the call.","triggerScenarios":"json.Marshal(payload) returns an error inside writeRPCMessage, called from rpcRequestOverIO or rpcNotifyOverIO when sending a request/notification to the codex app-server.","commonSituations":"A params struct gained an unsupported field type (e.g. json.Number misuse, cyclic pointer graph); NaN/Inf floats in numeric options; passing an unsupported value type as a param.","solutions":["Inspect the payload type being passed to rpcRequestOverIO/rpcNotifyOverIO and ensure all fields are JSON-serializable.","Check for NaN/Inf float values or cyclic references introduced by recent code changes.","Validate the marshaling with a small test: `json.Marshal(params)` and inspect the error text, which names the offending Go type.","Upgrade or downgrade to a matching connector/codex version combination if this started after an update (struct drift)."],"exampleFix":"// before: unmarshalable field\nparams := struct{ At time.Time }{At: time.Now()} // ok, but ensure no channels/funcs\n// after: verify serialization before send\nif _, err := json.Marshal(params); err != nil {\n    return fmt.Errorf(\"codex: invalid rpc params: %w\", err)\n}","handlingStrategy":"validation","validationCode":"// validate payload serializability before sending\nif _, err := json.Marshal(payload); err != nil {\n    return fmt.Errorf(\"rpc payload not JSON-serializable: %w\", err)\n}","typeGuard":"func isMarshalable(v any) bool {\n    _, err := json.Marshal(v)\n    return err == nil\n}","tryCatchPattern":"err := rpcNotifyOverIO(stdin, ctx, \"initialized\")\nif err != nil && strings.Contains(err.Error(), \"encode rpc message\") {\n    slog.Error(\"rpc payload contains unmarshalable values\", \"err\", err)\n    // fix payload construction; a retry with the same payload will fail identically\n}","preventionTips":["Keep RPC param structs limited to JSON-safe types (no channels, funcs, or cycles)","Guard against NaN/Inf floats in numeric parameters","Add a unit test marshaling every params type used in RPC calls","Let encoding/json tag hygiene (`json:\"...\"`) define the wire contract explicitly"],"tags":["codex","json-rpc","json-marshal","serialization"],"backgroundTag":"json-marshal-failed","analyzedSha":"4000b2338aa6e850c99df54f8b0ed6ed7460b401","analyzedAt":"2026-09-06T11:45:09.575Z","contentChangedAt":"2026-09-06T11:45:09.575Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}