fix(resume): allow passing a prompt via stdin while resuming using --resume (#13520)

packages/cli/src/config/config.test.ts

@@ -435,37 +435,15 @@ describe('parseArguments', () => {
     debugErrorSpy.mockRestore();
   });
 
-  it('should throw an error when resuming a session without prompt in non-interactive mode', async () => {
+  it('should allow resuming a session without prompt argument in non-interactive mode (expecting stdin)', async () => {
     const originalIsTTY = process.stdin.isTTY;
     process.stdin.isTTY = false;
     process.argv = ['node', 'script.js', '--resume', 'session-id'];
 
-    const mockExit = vi.spyOn(process, 'exit').mockImplementation(() => {
-      throw new Error('process.exit called');
-    });
-
-    const mockConsoleError = vi
-      .spyOn(console, 'error')
-      .mockImplementation(() => {});
-    const debugErrorSpy = vi
-      .spyOn(debugLogger, 'error')
-      .mockImplementation(() => {});
-
     try {
-      await expect(parseArguments({} as Settings)).rejects.toThrow(
-        'process.exit called',
-      );
-
-      expect(debugErrorSpy).toHaveBeenCalledWith(
-        expect.stringContaining(
-          'When resuming a session, you must provide a message via --prompt (-p) or stdin',
-        ),
-      );
-      expect(mockConsoleError).toHaveBeenCalled();
+      const argv = await parseArguments({} as Settings);
+      expect(argv.resume).toBe('session-id');
     } finally {
-      mockExit.mockRestore();
-      mockConsoleError.mockRestore();
-      debugErrorSpy.mockRestore();
       process.stdin.isTTY = originalIsTTY;
     }
   });

packages/cli/src/config/config.ts

@@ -262,11 +262,6 @@ export async function parseArguments(settings: Settings): Promise<CliArgs> {
       if (argv['prompt'] && argv['promptInteractive']) {
         return 'Cannot use both --prompt (-p) and --prompt-interactive (-i) together';
       }
-      if (argv['resume'] && !argv['prompt'] && !process.stdin.isTTY) {
-        throw new Error(
-          'When resuming a session, you must provide a message via --prompt (-p) or stdin',
-        );
-      }
       if (argv['yolo'] && argv['approvalMode']) {
         return 'Cannot use both --yolo (-y) and --approval-mode together. Use --approval-mode=yolo instead.';
       }