From 218fe8b892b8b4e5532e22f5ac5b973b97e37cc2 Mon Sep 17 00:00:00 2001
From: can1357 <me@can.ac>
Date: Wed, 13 May 2026 05:24:33 +0200
Subject: [PATCH] fix(packages/coding-agent): resolved JS display fallback for
 noncloneable values

- Handled structured-clone failures in JsRuntime.display by falling back to text output.
- Added regression coverage for non-structured-cloneable JS display output.
---
 packages/coding-agent/src/eval/js/shared/runtime.ts | 11 ++++++++++-
 packages/coding-agent/test/core/js-executor.test.ts |  7 +++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/packages/coding-agent/src/eval/js/shared/runtime.ts b/packages/coding-agent/src/eval/js/shared/runtime.ts
index 475fa474f..9b97b593b 100644
--- a/packages/coding-agent/src/eval/js/shared/runtime.ts
+++ b/packages/coding-agent/src/eval/js/shared/runtime.ts
@@ -4,6 +4,8 @@ import * as path from "node:path";
 import { pathToFileURL } from "node:url";
 import * as util from "node:util";
 
+import { logger } from "@oh-my-pi/pi-utils";
+
 import { ToolError } from "../../../tools/tool-errors";
 import { createHelpers, type HelperBundle } from "./helpers";
 import { awaitMaybePromise, indirectEval } from "./indirect-eval";
@@ -111,7 +113,14 @@ export class JsRuntime {
 				hooks.onDisplay({ type: "image", data: record.data, mimeType: record.mimeType });
 				return;
 			}
-			hooks.onDisplay({ type: "json", data: structuredClone(value) });
+			try {
+				hooks.onDisplay({ type: "json", data: structuredClone(value) });
+			} catch (err) {
+				logger.debug("js displayValue: value is not structured-cloneable, falling back to text", {
+					error: err instanceof Error ? err.message : String(err),
+				});
+				hooks.onText(`${Object.prototype.toString.call(value)}\n`);
+			}
 			return;
 		}
 		hooks.onText(`${String(value)}\n`);
diff --git a/packages/coding-agent/test/core/js-executor.test.ts b/packages/coding-agent/test/core/js-executor.test.ts
index 552ee47c3..50a3652eb 100644
--- a/packages/coding-agent/test/core/js-executor.test.ts
+++ b/packages/coding-agent/test/core/js-executor.test.ts
@@ -409,4 +409,11 @@ describe("executeJs", () => {
 		expect(result.exitCode).toBe(0);
 		expect(result.output.trim()).toBe("7");
 	});
+	it("falls back to text display when the final expression value is not structured-cloneable", async () => {
+		const result = await executeJs("({ fn: () => 1 });", { sessionId, session, sessionFile });
+		expect(result.exitCode).toBe(0);
+		expect(result.output).toContain("[object Object]");
+		// No JSON display because structuredClone fails on the embedded function.
+		expect(result.displayOutputs.filter(o => o.type === "json")).toHaveLength(0);
+	});
 });