X apps (LibreOffice, Thunderbird) fail to launch with failure to open display (no Xmir is running)

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

Incomplete for Xmir. Running it manually from ssh launches successfully:

mirrun Xmir :1 -rootless --desktop_file_hint=unity8 & sleep 2 ; env DISPLAY=:1 thunderbird

So it sounds like U8 or Libertine isn't launching it correctly.

Oh, the reason is in your log:

Feb 27 16:40:07 kg-Studio-1737 thunderbird[7543]: Error: cannot open display: :0

That means U8/Libertine failed to launch Xmir (or wait for Xmir) prior to running thunderbird.

Strange that starting Xmir in advance of launching Thunderbird from the drawer doesn't help. This suggests Thunderbird might be having trouble finding or accessing (apparmor?) the X socket.

The log shows Firefox is being run natively under Unity 8 (no Xmir). Firefox is known to not be built natively for Mir, so it's not a surprise that it it not start.

Assuming that an Xmir instance should be launched just in case for any and all applications run under Unity 8 was purposefully disabled to prevent unwanted empty black windows from covering the screen.

fwiw, this isn't a libertine app - this is just the preinstalled FF that's already part of the image.

also, the bug for LO calc is slightly different ( bug 1668425 ) even tho it was marked as a duplicate. I just want to call it out here separately since it doesn't just close the window like the other apps.

Libreoffice is a bit different yes, because of its splash screen. But your log in bug 1668425 confirms it's exactly the same problem as this one.

The solution it seems is for Unity8 to have an Xmir -rootless started and ready at login to support legacy X apps (that are not pure GTK). Only problem with that is that you will then hit bug 1577641.

Sorry, Firefox has its own issues -> bug 1668409

If we could get a fix for bug 1577641 then this would be easy to solve (in the most efficient way): Just start an 'Xmir -rootless ...' at login.

That way you don't need custom launcher magic for every X app to start an X server.

Nope, shared Xmir not a solution, we need each client to connect in a separate session, to securely identify it. And there's security considerations for that as well.

Not to mention gtk, for example, just probes available display servers and uses the first one that works, which could very well result in them running under X, when they should run natively.

In that case we'll actually have one Xmir process per app (which is probably OK for resources).

That's more elegant, and more secure, than trying to hack Xmir to emit multiple connections to the Mir server. And it works right now without modifying code.

Also, it appears you can uniquely identify an Xmir instance to the shell already using 'Xmir -mir <appid>'.

This bug was fixed in the package ubuntu-app-launch - 0.10+17.04.20170307.1-0ubuntu1

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ubuntu-app-launch (0.10+17.04.20170307.1-0ubuntu1) zesty; urgency=medium

  * XMir by default for Legacy apps (LP: #1668429)

 -- Ted Gould <email address hidden> Tue, 07 Mar 2017 19:07:32 +0000

With that "fix", now qt5 are unusable as they go under XMir.

*qt5 apps I mean

the issue with Qt5 will be covered under bug 1670751