Leaving room freezes client

[rokups]

Attempt to leave any room freezes application. It looks like so:

And produces this spam in console:

    61.539: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 48158, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    61.539: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 48169, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    61.544: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 48310, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    61.575: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 48486, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    63.486: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 48673, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    71.549: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 48995, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    72.194: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 49049, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    72.209: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 49091, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    72.212: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 49132, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    72.227: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 49173, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    72.244: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 49218, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    72.259: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 49259, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    72.275: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 49300, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    72.291: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 49341, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    72.307: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 49382, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    72.323: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 49423, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    72.339: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 49464, resource id: 88087392, major code: 130 (Unknown), minor code: 3
    72.356: [warning] - QXcbConnection: XCB error: 8 (BadMatch), sequence: 49505, resource id: 88087392, major code: 130 (Unknown), minor code: 3

Clicking logout button presents confirmation dialog properly and it all works.

OS: Archlinux
Desktop: KDE Plasma5

[Ralith]

Bringing up the room switcher produces similar results for me. The room switcher actually works fine, you just can't see it at all--only a rectangular cutout in the dimming.

[mujx]

Is this still an issue on KDE? Does it happen with any other modal? (e.g logout)

[rokups]

Still happens when leaving room. Logout modal works fine.

[Fryboyter]

Just tested the current Git version. Under Arch and Plasma (all updates are installed) I have the same problem as rokups. The error messages are also identical.

[mujx]

On my system only the Logout dialog works correctly. All the others have the same problematic behavior.

[Fryboyter]

The changes seem to have fixed the problem. Just entered and left several rooms without the client being frozen.

[mujx]

@Fryboyter How about the other dialogs? (join/create room, logout etc)

[rokups]

@mujx join/create room/leave room all have this issue. Logout dialog however works properly.

[rokups]

I am afraid things are worse now.

Now every dialog except one is invisible:

"Create room" dialog looks like this:

[mujx]

I tested the fix on the following setup in Debian 9

1. Plasma version 5.8.6
2. KDE Frameworks 5.28.0
3. Qt version 5.7.1

[rokups]

Versions here:

• Archlinux
• Plasma 5.12
• KDE Frameworks 5.43
• Qt 5.10.1

[mujx]

I actually I think this is an issue with qt 5.10.1. I got the exact same problem regardless of linux or kde. Could you try with 5.10.0 or older?

Related comment on #nheko:matrix.org

[rokups]

You are right! Qt 5.10.0 works flawless

[mujx]

Closing as resolved because this is a qt bug. I will try to create a minimal example and file a bug report. @rokups Thanks for the help!