selenium.common.exceptions.InvalidArgumentException: Message: invalid argument: 'name' must be a string error switching window handles using Selenium

Question

If I use the piece of code below:

driver.execute_script("window.open('');")
driver.switch_to.window(driver.window_handles[1])
driver.get(url)
driver.switch_to.window(driver.window_handles[0])

It will throw back an error at me.

selenium.common.exceptions.InvalidArgumentException: Message: invalid argument: 'name' must be a string

The same thing happens if I use any code at all with driver.switch_to.window(driver.window_handles[1]) What can I do to fix this as it is quite annoying because it basically destroys the whole code? I'm using opera.

Full traceback:

Traceback (most recent call last):
  File "C:\Users\user\PycharmProjects\websitemonitorcsshtml\switchtab.py", line 11, i
n <module>
    driver.switch_to.window(driver.window_handles[1])
  File "C:\Users\user\PycharmProjects\Giraffe\venv\lib\site-packages\selenium\webdriv
er\remote\switch_to.py", line 134, in window
    self._w3c_window(window_name)
  File "C:\Users\user\PycharmProjects\Giraffe\venv\lib\site-packages\selenium\webdriv
er\remote\switch_to.py", line 143, in _w3c_window
    send_handle(window_name)
  File "C:\Users\user\PycharmProjects\Giraffe\venv\lib\site-packages\selenium\webdriv
er\remote\switch_to.py", line 139, in send_handle
    self._driver.execute(Command.SWITCH_TO_WINDOW, {'handle': h})
  File "C:\Users\user\PycharmProjects\Giraffe\venv\lib\site-packages\selenium\webdriv
er\remote\webdriver.py", line 418, in execute
    self.error_handler.check_response(response)
  File "C:\Users\user\PycharmProjects\Giraffe\venv\lib\site-packages\selenium\webdriv
er\remote\errorhandler.py", line 243, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.InvalidArgumentException: Message: invalid argument: 'name'
 must be a string
  (Session info: chrome=95.0.4638.69)
  (Driver info: operadriver=95.0.4638.54 (d31a821ec901f68d0d34ccdbaea45b4c86ce543e-ref
s/branch-heads/4638@{#871}),platform=Windows NT 10.0.19042 x86_64)

Here is the full code:

from selenium import webdriver 
from selenium.webdriver.opera.options import Options 

options = Options() 
options.add_experimental_option('excludeSwitches', ['enable-logging']) 
DRIVER_PATH = 'C:\Python27\Scripts\operadriver.exe' 
driver = webdriver.Opera(options=options, executable_path=DRIVER_PATH)
driver.get("stackoverflow.com/")
driver.execute_script("window.open('');")
driver.switch_to.window(driver.window_handles[1])
driver.get("github.com/")
driver.switch_to.window(driver.window_handles[0])

Answer 1

Window Switching

1. Before attempting to switch the window, store the parent window handle for future use.

   window_before  = driver.current_window_handle
   

2. After opening the new window store the window handles in a list.

   windows_after = driver.window_handles
   

3. While switchin windows instead of using indexes e.g. window_handles[0], window_handles[1], use List Comprehension to locate the new window as follows:

   new_window = [x for x in windows_after if x != window_before][0]
   

---

Solution

Complete Window Switching code block:

driver.get("https://stackoverflow.com/")
window_before = driver.current_window_handle
print("First Window Handle is : %s" %window_before)
print("Page Title before Tab Switching is : %s" %driver.title)
driver.execute_script("window.open('','_blank');")
WebDriverWait(driver, 10).until(EC.number_of_windows_to_be(2))
windows_after = driver.window_handles
new_window = [x for x in windows_after if x != window_before][0]
driver.switch_to.window(new_window)
driver.get("https://www.selenium.dev/")
print("Second Window Handle is : %s" %new_window)
print("Page Title after Tab Switching is : %s" %driver.title)
driver.switch_to.window(window_before)
print("Window Handle is : %s" %window_before)
print("Page Title after Reverse Tab Switching is : %s" %driver.title)
driver.quit()

You have to add the following imports:

from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC

Console Output:

First Window Handle is : CDwindow-9E723D48DFB59B9B6BCB992EFE3C6695
Page Title before Tab Switching is : Stack Overflow - Where Developers Learn, Share, & Build Careers
Second Window Handle is : CDwindow-9CCD4B7DD7F5916788A422F24D476BC8
Page Title after Tab Switching is : Selenium
Window Handle is : CDwindow-9E723D48DFB59B9B6BCB992EFE3C6695
Page Title after Reverse Tab Switching is : Stack Overflow - Where Developers Learn, Share, & Build Careers