1491971 - Hangs in "WebDriver:FullscreenWindow"

Status: RESOLVED WORKSFORME

(Remote Protocol :: Marionette, defect, P3)

Description

[Henrik Skupin [:whimboo][⌚️UTC+1]]

Similar to bug 1489955 the "WebDriver:FullscreenWindow" command hangs and doesn't return. As result Firefox gets killed after reaching the timeout.

This is actually a permafail for wpt.fyi test results, and marks all the tests in `set.py` as missing:

https://staging.wpt.fyi/results/webdriver/tests/set_window_rect/set.py?sha=d36d9f4077

Here the log file from Taskcluster:

https://taskcluster-artifacts.net/ANhqpIf7TfWvXpyS3lk9XA/0/public/logs/live_backing.log

> 28:55.63 .. 1537208827023	Marionette	TRACE	0 -> [0,945,"WebDriver:FullscreenWindow",{}]
> 31:54.48 .. TEST_END: TIMEOUT, expected OK

Andreas, given that you worked on the fullscreen / set window rect implementation for Marionette, and the failure seems to be very specific to Linux, can you please work on that bug? 

If we cannot find the underlying issue I would even be happy with using the TimedPromise for waiting of the expected events. That way we could at least return a failure after eg. 15s, and don't hang forever.

We should treat this failure with high priority.

Comment 1

[Henrik Skupin [:whimboo][⌚️UTC+1]]

Please note that when you check the above TaskCluster log file all window tests which call `WebDriver:Fullscreen` hang. So this affects the fullscreen, maximize, minimize, and set window rect commands.

Comment 2

[Andreas Tolfsen ❲:ato❳]

I can’t work on this right now, but can take a look once I’ve
finished my P1s and my other P2s.

Comment 3

[David Burns :automatedtester]

Setting this to P3 as it's only wpt.fyi. If it moves to our CI then we can revisit

Comment 4

[Andreas Tolfsen ❲:ato❳]

There are some fundamental restrictions we can’t get with window
manipulation.  If you run Firefox in Xvfb without a window manager,
it will not be possible to put the browser into fullscreen mode.
To make the matter worse, we also cannot detect if the browser is
run inside a capable WM.  Our only option in this case is to fall
back to a timeout, hoping the browser has reached its dimensions
but the window state will likely not reach "fullscreen".

Comment 5

[Andreas Tolfsen ❲:ato❳]

This should be solved with https://bugzilla.mozilla.org/show_bug.cgi?id=1492499.

Comment 6

[Henrik Skupin [:whimboo][⌚️UTC+1]]

No timeout anymore for wpt.fyi fullscreen tests. Thanks a lot!

https://wpt.fyi/results/webdriver/tests/fullscreen_window?label=experimental

Comment 7

[Henrik Skupin [:whimboo][⌚️UTC+1]]

This is not completely fixed. Bug 1508101 was raised recently.

Comment 8

[Henrik Skupin [:whimboo][⌚️UTC+1]]

We haven't seen hangs for this command for quite some time. As such lets close this bug.