[SRU] qt6-base/6.2.4+dfsg-10 to jammy

[Dan Bryant]

[Impact]

 * The current version of qtbase6 in Ubuntu Jammy is not working correctly due to bug https://bugs.launchpad.net/ubuntu/+source/qt6-base/+bug/1970057. This issue has been resolved in Kinetic package qt6-base_6.2.4+dfsg-10.

[Test Plan]

 * As Tom Stevens copied into the bug report:

 1. Check the output of qtdiag from qt6-tools-dev-tools, and verify the paths exist.
 a) Run "qtdiag --no-vulkan --no-rhi --no-gl | grep Path"
 b) verify that the paths actually exist, in particular DataPath: /share/qt6 does not exist on jammy.

 2. Build the Qt supplied simplebrowser example, and verify it launches without error
 a) apt-get source libqt6webenginecore6
 b) cd qt6-webengine-6.2.4+dfsg/examples/webenginewidgets/simplebrowser
 c) mkdir bld
 d) cd bld
 e) cmake -DCMAKE_BUILD_TYPE=Release ..
 f) cmake --build .
 g) ./simplebrowser
 An example of output from a failure is attached as faillog.txt. In particular note the failure to find resources at /share:
   Qt WebEngine resources not found at /share/qt6/resources. Trying parent directory...
   Qt WebEngine resources not found at /share/qt6. Trying application directory...
and the resulting segmentation fault:
  Segmentation fault (core dumped)
   a) Check the output of qtdiag from qt6-tools-dev-tools, and verify the paths exist.
   b) Run "qtdiag --no-vulkan --no-rhi --no-gl | grep Path"
   c) verify that the paths actually exist, in particular DataPath: /share/qt6 does not exist on jammy.

[Scope]

 * Use package from Ubuntu 22.10 (Kinetic) qt6-base_6.2.4+dfsg-10.

[Other Info]

 * I have already done this in a PPA, it is published here: https://launchpad.net/~justdan96/+archive/ubuntu/qt6-backports-minimal/+packages?field.name_filter=&field.status_filter=published&field.series_filter=jammy
 * I know this isn't the latest qtbase6 package in Kinetic - but backporting just this package, at specifically version 6.2.4, avoids having to release all of the Qt6 packages as backports and resolves the specific bug linked above.

[Where problems could occur]

* As Tom Stevens copied into the bug report:

* The change in 6.2.4+dfsg-8 restores the configuration settings that were used to build qtbase-opensource-src (5.14.2+dfsg-3) through qtbase-opensource-src (5.15.3+dfsg-2). The setting was lost on the transition from the Qt5 qmake build to the Qt6 cmake build.

* The change causes QLibraryInfo to use paths known at build time instead of trying to dynamically establish the paths. This will fail if the package is relocated to a different location from that which it is build for. Since the package isn't relocatable this shouldn't be a problem.

[Thomas Ward (teward)]

This sounds like something that should be an SRU not a backport. Especially since theres an open bug on this and a patch exists.

[Dan Bryant (justdan96)]

Happy to change this to be an SRU rather than a backport, I'll get started on that.

[Dan Bryant (justdan96)]

The package is now published in the PPA linked above, please let me know if there is anything else you need. Diffs are available here: https://launchpad.net/~justdan96/+archive/ubuntu/qt6-backports-minimal/+files/qt6-base_6.2.4+dfsg-2ubuntu1_6.2.4+dfsg-10.diff.gz https://launchpad.net/~justdan96/+archive/ubuntu/qt6-backports-minimal/+files/qt6-base_6.2.4+dfsg-10_6.2.4+dfsg-10ubuntu0.22.04.1.diff.gz

[Dan Bryant (justdan96)]

The debdiff from 6.2.4+dfsg-2ubuntu1 to 6.2.4+dfsg-10ubuntu0.22.04.1 (from the PPA) is attached.

[Robie Basak (racb)]

Thank you for working on this! For an SRU, the change needs to be minimal. Could you narrow down the debdiff to contain only the bug being fixed, please?

[Robie Basak (racb)]

Please also use the bug you're fixing, rather than creating another one. So I think this bug probably needs to be marked as a duplicate of bug 1970057, and then use only that bug for working on this?

[Dan Bryant (justdan96)]

As <rbasak> mentioned on IRC, I am attaching a minimal debdiff that just resolves the bug in https://bugs.launchpad.net/ubuntu/+source/qt6-base/+bug/1970057. This is copied from the original bug.

[Dan Bryant (justdan96)]

This is a duplicate of 1970057 and has been marked as invalid.