"Advanced" tab is missing from Print dialog in Qt5 applications

[Brett Keller]

Please backport Qt patch 213391 to qtbase-opensource-src in Bionic:
https://codereview.qt-project.org/#/c/213391/

[Impact]
On Kubuntu 18.04 (bionic), any applications using Qt5 are unable to fully configure printers from within the "Print..." dialog because the "Advanced" tab is no longer present. Settings shown here will differ by printer, but this includes important settings such as paper type (plain, glossy, photo, etc.), print resolution, and ink usage strategies. Gwenview and Okular are notable affected applications. GTK applications are unaffected and do show the advanced options provided by the printer driver. As a workaround for Qt5 applications, the printer *default* advanced settings can be successfully accessed and changed from within the "Printers" section of Plasma's "System Settings", but this is cumbersome, unintuitive, and is not the intended way of interacting with these settings on a per-print-job basis.

[Additional Information]
This was identified as a bug in Qt5 upstream:
https://bugreports.qt.io/browse/QTBUG-54464

The bug was fixed upstream in Qt 5.11, but Bionic is stable on Qt 5.9. I'd like to request that this patch be backported to Bionic, please.

[Regression Potential]
OpenSUSE has already backported this patch to their Qt 5.9 stable branch, so there is precedent for this patch being low risk:
https://build.opensuse.org/package/view_file/KDE:Qt:5.9/libqt5-qtbase/0010-Reintroduce-the-Advanced-tab-in-the-QPrintProperties.patch?expand=1

Software Versions:

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.3 LTS
Release: 18.04
Codename: bionic

$ apt-cache policy libqt5printsupport5
libqt5printsupport5:
  Installed: 5.9.5+dfsg-0ubuntu2.4
  Candidate: 5.9.5+dfsg-0ubuntu2.4
  Version table:
 *** 5.9.5+dfsg-0ubuntu2.4 500
        500 http://us.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     5.9.5+dfsg-0ubuntu2.1 500
        500 http://security.ubuntu.com/ubuntu bionic-security/main amd64 Packages
     5.9.5+dfsg-0ubuntu1 500
        500 http://us.archive.ubuntu.com/ubuntu bionic/main amd64 Packages

[Dmitry Shachnev (mitya57)]

Thank you for filing this bug and adding the required SRU information. But I have to reject it:

Actually, that patch is just the tip of the iceberg.

It does not apply cleanly unless you backport many other patches. If you look at OpenSUSE, they have added 11 patches related to printing dialog and also 17 other patches related to printing:

https://build.opensuse.org/request/show/569841
https://build.opensuse.org/package/show/KDE:Qt:5.9/libqt5-qtbase

Some of these patches change private API, so they require rebuild of packages relying on it. Unfortunately, this does not meet our SRU criteria.

[Brett Keller (blkeller)]

Well, thanks anyway for looking into it. It's disappointing, but I can totally understand why this won't be backported if the patch is that complex and touches that many other packages. I'll just use the workaround until I get the updated Qt stack in 20.04.