fix(clipboard): enforce UTF-8 encoding for Windows clipboard output (#460)

src/server/clipboard.test.ts

@@ -91,11 +91,28 @@ describe("Clipboard helper", () => {
 		expect(text).toBe("windows clipboard text")
 		expect(spawn).toHaveBeenCalledWith(
 			"powershell.exe",
-			expect.arrayContaining(["Get-Clipboard -Raw"]),
-			expect.any(Object),
+			expect.arrayContaining([
+				expect.stringMatching(
+					/\[Console\]::OutputEncoding\s*=\s*\[System\.Text\.Encoding\]::UTF8;\s*Get-Clipboard -Raw/,
+				),
+			]),
+			expect.objectContaining({ windowsHide: true }),
 		)
 	})
 
+	it("should keep a character split across stdout chunks", async () => {
+		vi.mocked(os.platform).mockReturnValue("win32")
+		const proc = createMockProcess({})
+		vi.mocked(spawn).mockReturnValue(proc)
+		const rocket = Buffer.from("🚀")
+
+		const pending = getSystemClipboard()
+		proc.stdout.emit("data", rocket.subarray(0, 2))
+		proc.stdout.emit("data", rocket.subarray(2))
+
+		await expect(pending).resolves.toBe("🚀")
+	})
+
 	it("should read clipboard on linux using fallback when first command fails", async () => {
 		vi.mocked(os.platform).mockReturnValue("linux")
 		const origEnv = process.env.XDG_SESSION_TYPE

src/server/clipboard.ts

@@ -34,17 +34,20 @@ function spawnWithStdin(
  */
 function spawnCaptureOutput(cmd: string, args: string[]): Promise<string> {
 	return new Promise((resolve, reject) => {
-		const child = spawn(cmd, args, { stdio: ["ignore", "pipe", "ignore"] })
-		let output = ""
+		const child = spawn(cmd, args, {
+			stdio: ["ignore", "pipe", "ignore"],
+			windowsHide: true,
+		})
+		const chunks: Buffer[] = []
 
 		child.stdout.on("data", (chunk: Buffer) => {
-			output += chunk.toString("utf-8")
+			chunks.push(chunk)
 		})
 
 		child.on("error", reject)
 
 		child.on("close", (code) => {
-			if (code === 0) resolve(output)
+			if (code === 0) resolve(Buffer.concat(chunks).toString("utf-8"))
 			else reject(new Error(`${cmd} exited with code ${code}`))
 		})
 	})
@@ -64,7 +67,7 @@ export async function getSystemClipboard(): Promise<string> {
 		const text = await spawnCaptureOutput("powershell.exe", [
 			"-NoProfile",
 			"-Command",
-			"Get-Clipboard -Raw",
+			"[Console]::OutputEncoding = [System.Text.Encoding]::UTF8; Get-Clipboard -Raw",
 		])
 		return text.replace(/\r?\n$/, "")
 	}