robotframework / robotframework/SeleniumLibrary
Switch Window sporadically fails with TypeError
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Beschreibung
Observed with
Python 3.13.0
SeleniumLibrary 6.7.1
Scenario
I have the following scenario in a test which fails sporadically:
- Link in an (internal) application is clicked which opens a different URL in a new tab
Switch Windowis called with the expected URL as locator and10 sas 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?
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Rechercherichtung
Beginne in src/SeleniumLibrary/locators/windowmanager.py bei der Zeile, die das Ergebnis von execute_script("return [ window.id, window.name ];") entpackt. Reproduziere das Switch Window-Szenario mit einem verzögert geöffneten neuen Tab und untersuche die vorhandene Ausnahmebehandlung und den Timeout-Ablauf. Erledigt ist es, wenn der sporadisch auftretende TypeError behoben ist, ohne den Fensterwechsel oder das angeforderte Timeout-Verhalten zu beeinträchtigen.
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Bewertung
- Tech-Stack
- python
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- testing-qa
- Issue-Typ
- Bug
- Schwierigkeit
- 4/5
- Geschätzter Aufwand
- 3-5 Tage
- Aktivitätsstatus
- Veraltet
- Klarheit
- Größtenteils klar
- Anfängerfreundlichkeit
- 35/100