fix: avoid duplicate terminal paste shortcuts (#400)

* fix: avoid duplicate terminal paste shortcuts

* chore: format with prettier [skip ci]

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

frontend/src/renderer/components/XtermTerminal.test.tsx

@@ -277,16 +277,54 @@ describe("XtermTerminal", () => {
 		expect(window.ao!.clipboard.writeText).not.toHaveBeenCalled();
 	});
 
-	it("pastes from the Electron clipboard on Windows/Linux paste shortcuts", async () => {
+	it.each(["Linux x86_64", "Win32"])(
+		"pastes once from the Electron clipboard on Ctrl+Shift+V for %s",
+		async (platform) => {
+			setNavigatorPlatform(platform);
+			const onInput = vi.fn();
+			window.ao!.clipboard.readText = vi.fn().mockResolvedValue("hello\nworld");
+			const { container } = render(
+				<XtermTerminal theme="dark" onReady={(terminal) => terminal.onUserInput(onInput)} />,
+			);
+
+			const event = {
+				key: "v",
+				metaKey: false,
+				ctrlKey: true,
+				shiftKey: true,
+				altKey: false,
+				preventDefault: vi.fn(),
+				stopPropagation: vi.fn(),
+			} as unknown as KeyboardEvent;
+			const allowed = state.lastTerminal!.keyHandler!(event);
+			const pasteEvent = new Event("paste", { bubbles: true, cancelable: true }) as ClipboardEvent;
+			Object.defineProperty(pasteEvent, "clipboardData", {
+				value: { getData: vi.fn().mockReturnValue("native paste") },
+			});
+			container.firstElementChild!.dispatchEvent(pasteEvent);
+			await Promise.resolve();
+
+			expect(allowed).toBe(false);
+			expect(event.preventDefault).toHaveBeenCalled();
+			expect(event.stopPropagation).toHaveBeenCalled();
+			expect(window.ao!.clipboard.readText).toHaveBeenCalledTimes(1);
+			expect(pasteEvent.defaultPrevented).toBe(true);
+			expect(onInput).toHaveBeenCalledTimes(1);
+			expect(onInput).toHaveBeenCalledWith("hello\rworld", "paste");
+		},
+	);
+
+	it("supports plain Ctrl+V paste on Windows", async () => {
+		setNavigatorPlatform("Win32");
 		const onInput = vi.fn();
-		window.ao!.clipboard.readText = vi.fn().mockResolvedValue("hello\nworld");
+		window.ao!.clipboard.readText = vi.fn().mockResolvedValue("windows paste");
 		render(<XtermTerminal theme="dark" onReady={(terminal) => terminal.onUserInput(onInput)} />);
 
 		const event = {
 			key: "v",
 			metaKey: false,
 			ctrlKey: true,
-			shiftKey: true,
+			shiftKey: false,
 			altKey: false,
 			preventDefault: vi.fn(),
 			stopPropagation: vi.fn(),
@@ -298,7 +336,36 @@ describe("XtermTerminal", () => {
 		expect(event.preventDefault).toHaveBeenCalled();
 		expect(event.stopPropagation).toHaveBeenCalled();
 		expect(window.ao!.clipboard.readText).toHaveBeenCalled();
-		expect(onInput).toHaveBeenCalledWith("hello\rworld", "paste");
+		expect(onInput).toHaveBeenCalledWith("windows paste", "paste");
+	});
+
+	it("suppresses a queued native paste event after a handled paste shortcut", async () => {
+		const onInput = vi.fn();
+		window.ao!.clipboard.readText = vi.fn().mockResolvedValue("shortcut paste");
+		const { container } = render(<XtermTerminal theme="dark" onReady={(terminal) => terminal.onUserInput(onInput)} />);
+
+		const event = {
+			key: "v",
+			metaKey: false,
+			ctrlKey: true,
+			shiftKey: true,
+			altKey: false,
+			preventDefault: vi.fn(),
+			stopPropagation: vi.fn(),
+		} as unknown as KeyboardEvent;
+		expect(state.lastTerminal!.keyHandler!(event)).toBe(false);
+		await new Promise((resolve) => window.setTimeout(resolve, 0));
+
+		const pasteEvent = new Event("paste", { bubbles: true, cancelable: true }) as ClipboardEvent;
+		Object.defineProperty(pasteEvent, "clipboardData", {
+			value: { getData: vi.fn().mockReturnValue("native paste") },
+		});
+		container.firstElementChild!.dispatchEvent(pasteEvent);
+		await Promise.resolve();
+
+		expect(pasteEvent.defaultPrevented).toBe(true);
+		expect(onInput).toHaveBeenCalledTimes(1);
+		expect(onInput).toHaveBeenCalledWith("shortcut paste", "paste");
 	});
 
 	it("supports classic Windows terminal copy and paste shortcuts", async () => {

frontend/src/renderer/components/XtermTerminal.tsx

@@ -68,6 +68,7 @@ function loadRenderer(term: Terminal): void {
 // xterm palette tracks the app theme (see lib/terminal-themes.ts + --term-* in
 // styles.css). The PTY content is still the agent's own ANSI output.
 const terminalThemes = buildTerminalThemes();
+const SUPPRESS_NATIVE_PASTE_MS = 100;
 
 // Erase scrollback (3J) + display (2J) and home the cursor — yyork's
 // terminalResetSequence. Deliberately NOT term.reset(): every pane PTY is a
@@ -102,7 +103,8 @@ function isTerminalPasteShortcut(event: KeyboardEvent): boolean {
 	if (event.key === "Insert") return event.shiftKey && !event.ctrlKey && !event.altKey && !event.metaKey;
 	if (event.key.toLowerCase() !== "v") return false;
 	if (event.metaKey) return true;
-	return event.ctrlKey && event.shiftKey;
+	if (event.ctrlKey && event.shiftKey && !event.altKey) return true;
+	return isWindowsPlatform() && event.ctrlKey && !event.shiftKey && !event.altKey && !event.metaKey;
 }
 
 function consumeTerminalShortcut(event: KeyboardEvent): void {
@@ -298,6 +300,20 @@ export function XtermTerminal(props: XtermTerminalProps) {
 			const bracketed = term.modes.bracketedPasteMode && term.options.ignoreBracketedPasteMode !== true;
 			emitUserInput(bracketPastedText(prepared, bracketed), "paste");
 		};
+		let suppressNextNativePaste = false;
+		let suppressPasteTimer: number | null = null;
+		const clearSuppressNativePaste = () => {
+			suppressNextNativePaste = false;
+			if (suppressPasteTimer !== null) {
+				window.clearTimeout(suppressPasteTimer);
+				suppressPasteTimer = null;
+			}
+		};
+		const suppressNativePasteOnce = () => {
+			suppressNextNativePaste = true;
+			if (suppressPasteTimer !== null) window.clearTimeout(suppressPasteTimer);
+			suppressPasteTimer = window.setTimeout(clearSuppressNativePaste, SUPPRESS_NATIVE_PASTE_MS);
+		};
 		const pasteFromClipboard = () => {
 			void aoBridge.clipboard
 				.readText()
@@ -320,6 +336,7 @@ export function XtermTerminal(props: XtermTerminalProps) {
 			}
 			if (isTerminalPasteShortcut(event)) {
 				consumeTerminalShortcut(event);
+				suppressNativePasteOnce();
 				pasteFromClipboard();
 				return false;
 			}
@@ -468,6 +485,10 @@ export function XtermTerminal(props: XtermTerminalProps) {
 		const pasteInput = (event: ClipboardEvent) => {
 			event.preventDefault();
 			event.stopPropagation();
+			if (suppressNextNativePaste) {
+				clearSuppressNativePaste();
+				return;
+			}
 			const text = event.clipboardData?.getData("text/plain") ?? "";
 			pasteText(text);
 		};
@@ -510,6 +531,7 @@ export function XtermTerminal(props: XtermTerminalProps) {
 			selectionChange.dispose();
 			host.removeEventListener("paste", pasteInput, true);
 			host.removeEventListener("compositionend", compositionInput, true);
+			clearSuppressNativePaste();
 			keyInput.dispose();
 			userInputListeners.clear();
 			try {