From 81cec1c38bcf09265a03b519552ebcd3f4eaae02 Mon Sep 17 00:00:00 2001
From: can1357 <me@can.ac>
Date: Mon, 25 May 2026 14:03:06 +0200
Subject: [PATCH] fix(clipboard): hardened WSL PowerShell fallback for headless
 environments

- Raised PowerShell timeout to 8s and swallowed reap errors to prevent unhandled throws on WSL interop.
- Fixed fallback logic so arboard is skipped when no display server is present on headless WSL.
- Added test coverage for the headless WSL short-circuit path.
---
 packages/coding-agent/src/utils/clipboard.ts   | 17 ++++++++++++++---
 .../coding-agent/test/utils/clipboard.test.ts  | 18 ++++++++++++++++--
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/packages/coding-agent/src/utils/clipboard.ts b/packages/coding-agent/src/utils/clipboard.ts
index ed24f769c..22438ee0a 100644
--- a/packages/coding-agent/src/utils/clipboard.ts
+++ b/packages/coding-agent/src/utils/clipboard.ts
@@ -1,6 +1,7 @@
 import { execSync } from "node:child_process";
 import type { ClipboardImage } from "@oh-my-pi/pi-natives";
 import * as native from "@oh-my-pi/pi-natives";
+import { logger } from "@oh-my-pi/pi-utils";
 
 function hasDisplay(): boolean {
 	return process.platform !== "linux" || Boolean(process.env.DISPLAY || process.env.WAYLAND_DISPLAY);
@@ -80,7 +81,7 @@ if ($img -ne $null) {
 }
 `;
 
-const POWERSHELL_TIMEOUT_MS = 5000;
+const POWERSHELL_TIMEOUT_MS = 8000;
 
 /**
  * Read a clipboard image through the Windows host's PowerShell.
@@ -104,6 +105,12 @@ async function readImageViaPowerShell(): Promise<ClipboardImage | null> {
 		try {
 			stdout = await new Response(proc.stdout).text();
 			await proc.exited;
+		} catch (err) {
+			// powershell.exe is a Windows process reached over WSL interop; if it
+			// doesn't reap cleanly, swallow the error so the dispatcher can fall
+			// through to the native bridge instead of throwing.
+			logger.warn("clipboard: powershell read failed", { error: String(err) });
+			return null;
 		} finally {
 			clearTimeout(timer);
 		}
@@ -136,8 +143,12 @@ export async function readImageFromClipboard(): Promise<ClipboardImage | null> {
 	if (isWsl()) {
 		const image = await readImageViaPowerShell();
 		if (image) return image;
-		// Fall through: arboard may still succeed on a future WSLg release.
-	} else if (!hasDisplay()) {
+		// Fall through: arboard may still succeed on a future WSLg release —
+		// but only when we actually have a display server. Headless WSL has
+		// no display, so arboard would reject anyway.
+	}
+
+	if (!hasDisplay()) {
 		return null;
 	}
 
diff --git a/packages/coding-agent/test/utils/clipboard.test.ts b/packages/coding-agent/test/utils/clipboard.test.ts
index c1cc0546b..94d1e4b13 100644
--- a/packages/coding-agent/test/utils/clipboard.test.ts
+++ b/packages/coding-agent/test/utils/clipboard.test.ts
@@ -97,9 +97,10 @@ describe("readImageFromClipboard on WSL", () => {
 		expect(nativeSpy).not.toHaveBeenCalled();
 	});
 
-	it("falls back to the native bridge when PowerShell returns no payload", async () => {
+	it("falls back to the native bridge when PowerShell returns no payload and a display is present", async () => {
 		setPlatform("linux");
 		process.env.WSL_INTEROP = "/run/WSL/1_interop";
+		process.env.WAYLAND_DISPLAY = "wayland-0";
 
 		spyPowershell([], "");
 		const nativeSpy = vi.spyOn(native, "readImageFromClipboard").mockResolvedValue(null);
@@ -110,9 +111,10 @@ describe("readImageFromClipboard on WSL", () => {
 		expect(nativeSpy).toHaveBeenCalledTimes(1);
 	});
 
-	it("falls back to the native bridge when PowerShell exits non-zero", async () => {
+	it("falls back to the native bridge when PowerShell exits non-zero (with display)", async () => {
 		setPlatform("linux");
 		process.env.WSL_DISTRO_NAME = "Ubuntu";
+		process.env.DISPLAY = ":0";
 
 		spyPowershell([], "noise", 1);
 		const nativeSpy = vi.spyOn(native, "readImageFromClipboard").mockResolvedValue(null);
@@ -120,6 +122,18 @@ describe("readImageFromClipboard on WSL", () => {
 		await readImageFromClipboard();
 		expect(nativeSpy).toHaveBeenCalledTimes(1);
 	});
+
+	it("returns null without invoking arboard on headless WSL when PowerShell yields nothing", async () => {
+		setPlatform("linux");
+		process.env.WSL_DISTRO_NAME = "Ubuntu";
+		// No DISPLAY / WAYLAND_DISPLAY — arboard would reject, so we must short-circuit.
+
+		spyPowershell([], "");
+		const nativeSpy = vi.spyOn(native, "readImageFromClipboard");
+
+		expect(await readImageFromClipboard()).toBeNull();
+		expect(nativeSpy).not.toHaveBeenCalled();
+	});
 });
 
 describe("readImageFromClipboard dispatch", () => {