Switch Window sporadically fails with TypeError

从 src/SeleniumLibrary/locators/windowmanager.py 中解包 execute_script("return [ window.id, window.name ];") 结果的那一行开始。使用延迟打开的新标签页重现 Switch Window 场景，并检查现有的异常处理和 timeout 流程。完成标准是解决间歇性 TypeError，同时不破坏窗口切换或请求的 timeout 行为。

Observed with

Python 3.13.0
SeleniumLibrary 6.7.1

Scenario

I have the following scenario in a test which fails sporadically:

1. Link in an (internal) application is clicked which opens a different URL in a new tab
2. Switch Window is called with the expected URL as locator and 10 s as a timeout

Expected behaviour

The new window is switched to. If the window is not immediately available/ready when this keyword is started, it should wait until the window can be switched to, within the given timeout limits.

Error

This works just fine most of the time, but occasionally I get the following error:
TypeError: cannot unpack non-iterable NoneType object
This error shows up pretty much instantly (within a few hundred ms), so the timeout is not taken into account.
However, in the associated screenshots, the expected page is always shown.

Analysis

I looked into the library's code and added some extra logging, which showed the error was coming from this line:
https://github.com/robotframework/SeleniumLibrary/blob/ce9d0ec510bd99c5a1b1cd114f767c7feeae1208/src/SeleniumLibrary/locators/windowmanager.py#L199

The call to self.driver.execute_script("return [ window.id, window.name ];") returns None, thus the assignment to the two variables fails with the above error.

Adding a 1 s sleep right before the call to execute_script makes the error no longer occur (even with many iterations of the test), so it does seem to be somehow timing related.
I guess there's a short timeframe where the window is there but not fully ready and this makes the function call fail? But I wasn't able to understand the exact nature of this presumed 'not ready' state so far.

Proposed solution

The TypeError could be added to the already present except, which successfully avoided failures due to this in my scenario.
Adding this would be trivial, but I'm not sure about the implications:

• does anything depend on the current behaviour that raises an error in this case (seems not, but I'm not super familiar with the library's codebase)?
• would it be appropriate to suppress this error in the library, given it is not fully understood what exactly the nature of the actual, underlying error is?
  Do you have any guidance how to proceed here?