From 76f0f1727c1adb953f907274edddf7ef8a8a3f6e Mon Sep 17 00:00:00 2001
From: Kiet Ho <hoakiet98@gmail.com>
Date: Sat, 31 Jan 2026 18:07:18 -0800
Subject: [PATCH] fix(desktop): trim trailing whitespace when copying text from
 terminal

Adds a copy handler that trims trailing whitespace from each line when
copying text from the terminal. This matches the default behavior of
iTerm2 and other popular terminal emulators.

Fixes #1018
---
 .../TabsContent/Terminal/helpers.ts           | 35 +++++++++++++++++++
 .../Terminal/hooks/useTerminalLifecycle.ts    |  3 ++
 2 files changed, 38 insertions(+)

diff --git a/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/Terminal/helpers.ts b/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/Terminal/helpers.ts
index a6dda7d0031..02548abe1c8 100644
--- a/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/Terminal/helpers.ts
+++ b/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/Terminal/helpers.ts
@@ -313,6 +313,41 @@ export interface PasteHandlerOptions {
 	isBracketedPasteEnabled?: () => boolean;
 }
 
+/**
+ * Setup copy handler for xterm to trim trailing whitespace from copied text.
+ *
+ * Terminal emulators fill lines with whitespace to pad to the terminal width.
+ * When copying text, this results in unwanted trailing spaces on each line.
+ * This handler intercepts copy events and trims trailing whitespace from each
+ * line before writing to the clipboard.
+ *
+ * Returns a cleanup function to remove the handler.
+ */
+export function setupCopyHandler(xterm: XTerm): () => void {
+	const element = xterm.element;
+	if (!element) return () => {};
+
+	const handleCopy = (event: ClipboardEvent) => {
+		const selection = xterm.getSelection();
+		if (!selection) return;
+
+		// Trim trailing whitespace from each line while preserving intentional newlines
+		const trimmedText = selection
+			.split("\n")
+			.map((line) => line.trimEnd())
+			.join("\n");
+
+		event.preventDefault();
+		event.clipboardData?.setData("text/plain", trimmedText);
+	};
+
+	element.addEventListener("copy", handleCopy);
+
+	return () => {
+		element.removeEventListener("copy", handleCopy);
+	};
+}
+
 /**
  * Setup paste handler for xterm to ensure bracketed paste mode works correctly.
  *
diff --git a/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/Terminal/hooks/useTerminalLifecycle.ts b/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/Terminal/hooks/useTerminalLifecycle.ts
index 4fbcd575eb4..52c66e4f32e 100644
--- a/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/Terminal/hooks/useTerminalLifecycle.ts
+++ b/apps/desktop/src/renderer/screens/main/components/WorkspaceView/ContentView/TabsContent/Terminal/hooks/useTerminalLifecycle.ts
@@ -14,6 +14,7 @@ import { DEBUG_TERMINAL, FIRST_RENDER_RESTORE_FALLBACK_MS } from "../config";
 import {
 	createTerminalInstance,
 	setupClickToMoveCursor,
+	setupCopyHandler,
 	setupFocusListener,
 	setupKeyboardHandler,
 	setupPasteHandler,
@@ -518,6 +519,7 @@ export function useTerminalLifecycle({
 			onWrite: handleWrite,
 			isBracketedPasteEnabled: () => isBracketedPasteRef.current,
 		});
+		const cleanupCopy = setupCopyHandler(xterm);
 
 		const handleVisibilityChange = () => {
 			if (document.hidden || isUnmounted) return;
@@ -562,6 +564,7 @@ export function useTerminalLifecycle({
 			cleanupFocus?.();
 			cleanupResize();
 			cleanupPaste();
+			cleanupCopy();
 			cleanupQuerySuppression();
 			unregisterClearCallbackRef.current(paneId);
 			unregisterScrollToBottomCallbackRef.current(paneId);