fix: copy command gets stuck (#6482)

Co-authored-by: Hriday Taneja <hridayt@google.com>

packages/cli/src/ui/utils/commandUtils.test.ts

@@ -5,7 +5,7 @@
  */
 
 import { vi, describe, it, expect, beforeEach, Mock } from 'vitest';
-import { spawn } from 'child_process';
+import { spawn, SpawnOptions } from 'child_process';
 import { EventEmitter } from 'events';
 import {
   isAtCommand,
@@ -186,6 +186,9 @@ describe('commandUtils', () => {
 
       it('should successfully copy text to clipboard using xclip', async () => {
         const testText = 'Hello, world!';
+        const linuxOptions: SpawnOptions = {
+          stdio: ['pipe', 'inherit', 'pipe'],
+        };
 
         setTimeout(() => {
           mockChild.emit('close', 0);
@@ -193,10 +196,11 @@ describe('commandUtils', () => {
 
         await copyToClipboard(testText);
 
-        expect(mockSpawn).toHaveBeenCalledWith('xclip', [
-          '-selection',
-          'clipboard',
-        ]);
+        expect(mockSpawn).toHaveBeenCalledWith(
+          'xclip',
+          ['-selection', 'clipboard'],
+          linuxOptions,
+        );
         expect(mockChild.stdin.write).toHaveBeenCalledWith(testText);
         expect(mockChild.stdin.end).toHaveBeenCalled();
       });
@@ -204,6 +208,9 @@ describe('commandUtils', () => {
       it('should fall back to xsel when xclip fails', async () => {
         const testText = 'Hello, world!';
         let callCount = 0;
+        const linuxOptions: SpawnOptions = {
+          stdio: ['pipe', 'inherit', 'pipe'],
+        };
 
         mockSpawn.mockImplementation(() => {
           const child = Object.assign(new EventEmitter(), {
@@ -232,14 +239,18 @@ describe('commandUtils', () => {
         await copyToClipboard(testText);
 
         expect(mockSpawn).toHaveBeenCalledTimes(2);
-        expect(mockSpawn).toHaveBeenNthCalledWith(1, 'xclip', [
-          '-selection',
-          'clipboard',
-        ]);
-        expect(mockSpawn).toHaveBeenNthCalledWith(2, 'xsel', [
-          '--clipboard',
-          '--input',
-        ]);
+        expect(mockSpawn).toHaveBeenNthCalledWith(
+          1,
+          'xclip',
+          ['-selection', 'clipboard'],
+          linuxOptions,
+        );
+        expect(mockSpawn).toHaveBeenNthCalledWith(
+          2,
+          'xsel',
+          ['--clipboard', '--input'],
+          linuxOptions,
+        );
       });
 
       it('should throw error when both xclip and xsel fail', async () => {

packages/cli/src/ui/utils/commandUtils.ts

@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { spawn } from 'child_process';
+import { spawn, SpawnOptions } from 'child_process';
 
 /**
  * Checks if a query string potentially represents an '@' command.
@@ -29,11 +29,13 @@ export const isSlashCommand = (query: string): boolean => query.startsWith('/');
 
 // Copies a string snippet to the clipboard for different platforms
 export const copyToClipboard = async (text: string): Promise<void> => {
-  const run = (cmd: string, args: string[]) =>
+  const run = (cmd: string, args: string[], options?: SpawnOptions) =>
     new Promise<void>((resolve, reject) => {
-      const child = spawn(cmd, args);
+      const child = options ? spawn(cmd, args, options) : spawn(cmd, args);
       let stderr = '';
-      child.stderr.on('data', (chunk) => (stderr += chunk.toString()));
+      if (child.stderr) {
+        child.stderr.on('data', (chunk) => (stderr += chunk.toString()));
+      }
       child.on('error', reject);
       child.on('close', (code) => {
         if (code === 0) return resolve();
@@ -44,11 +46,21 @@ export const copyToClipboard = async (text: string): Promise<void> => {
           ),
         );
       });
-      child.stdin.on('error', reject);
-      child.stdin.write(text);
-      child.stdin.end();
+      if (child.stdin) {
+        child.stdin.on('error', reject);
+        child.stdin.write(text);
+        child.stdin.end();
+      } else {
+        reject(new Error('Child process has no stdin stream to write to.'));
+      }
     });
 
+  // Configure stdio for Linux clipboard commands.
+  // - stdin: 'pipe' to write the text that needs to be copied.
+  // - stdout: 'inherit' since we don't need to capture the command's output on success.
+  // - stderr: 'pipe' to capture error messages (e.g., "command not found") for better error handling.
+  const linuxOptions: SpawnOptions = { stdio: ['pipe', 'inherit', 'pipe'] };
+
   switch (process.platform) {
     case 'win32':
       return run('clip', []);
@@ -56,11 +68,11 @@ export const copyToClipboard = async (text: string): Promise<void> => {
       return run('pbcopy', []);
     case 'linux':
       try {
-        await run('xclip', ['-selection', 'clipboard']);
+        await run('xclip', ['-selection', 'clipboard'], linuxOptions);
       } catch (primaryError) {
         try {
           // If xclip fails for any reason, try xsel as a fallback.
-          await run('xsel', ['--clipboard', '--input']);
+          await run('xsel', ['--clipboard', '--input'], linuxOptions);
         } catch (fallbackError) {
           const primaryMsg =
             primaryError instanceof Error