[regression] resizing some apps in Unity8 makes them distorted and freeze (usually software clients)

[dinamic]

ubuntu 17.04 unity8 + proposed and 16.04 + overlay PPA
mir 0.25
miral 0.25
unity8/zesty-proposed,now 8.15+17.04.20161207.1-0ubuntu1 amd64 [installed,automatic]

steps:
1)run gedit, nautilus, sol or whatever gtk+3 app ("ubuntu-app-launch sol" for ex). if you are not sure how to launch a gtk3 app run "ubuntu-app-launch-appids" first to see the appids and then "ubuntu-app-launch <appid>"

2) resize the window (the context gets stretched in a weird way and input doesn't work anymore)

see attached screenshot

Alternate test case:
$ mir_demo_client_progressbar 20 --desktop_file_hint=unity8

[dinamic (dinamic6661)]

qt5 apps seems to not be affected, so maybe it's a gtk3 mir bug?

[Daniel van Vugt (vanvugt)]

Invalid for GTK -- the toolkit can never cause such stretching.

Invalid for Mir -- Mir still works well elsewhere.

If your pixels are stretched then that's definitely a server/compositor bug. So QtMir or Unity8.

I can't reproduce the bug in regular 17.04 so assume it's just a problem in proposed...

[Daniel van Vugt (vanvugt)]

It's worth remembering a client can always (rightly or wrongly) refuse to render a new frame (e.g. it might freeze or it might be by design). It is always the server's responsibility to render the pixels of the last frame from the client correctly, never stretched out of proportion.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[dinamic (dinamic6661)]

it's the same on 16.04 + overlay ppa

[Daniel van Vugt (vanvugt)]

Hmm actually this /could/ be GTK's fault if GTK is now using GL rather than software rendering. Need to check.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Daniel van Vugt (vanvugt)]

Yes I can see some GL code in GTK's Mir backend. However I also notice the proposed new version of GTK in zesty got promoted yesterday. I've just tested it and can't reproduce the bug yet, so it seems unlikely to be caused by that.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Daniel van Vugt (vanvugt)]

Confirmed. The bug has now escaped proposed and is in zesty.

[Daniel van Vugt (vanvugt)]

Invalid for GTK. I have now reproduced the same bug using a pure Mir demo (which is software rendered in case that's relevant):

$ mir_demo_client_progressbar 20 --desktop_file_hint=unity8

[Daniel van Vugt (vanvugt)]

Also the bug does not exist in Mir demo servers.

This is just a QtMir/Unity8 bug.

[Lukáš Tinkl (lukas-kde)]

It resumes working when you shrink the window to its very minimal size but breaks again when enlarging it.

[Daniel van Vugt (vanvugt)]

Still experiencing this bug, particularly with AisleRiot Solitaire in Unity8.

[Alan Griffiths (alan-griffiths)]

Cannot reproduce in in miral-shell

[dinamic (dinamic6661)]

this bug makes all gtk3 apps unusable and hard to test :(

[Daniel van Vugt (vanvugt)]

OK, I think we have an answer. Now (probably) fixed as part of bug 1663062.

[Daniel van Vugt (vanvugt)]

Verified fixed here:

https://launchpad.net/~ci-train-ppa-service/+archive/ubuntu/2435/?field.series_filter=zesty