bug#57742: QT plugins from profile not found (QT_PLUGIN_PATH)

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

Hello,

Maxim Cournoyer <maxim.cournoyer@gmail.com> writes:

> Hello,
>
> Marek Paśnikowski <marekpasnikowski@protonmail.com> writes:
>
>> Hello.
>>
>> I found a piece of QT documentation on handling of plugins [1].
>>
>> Is it helpful to achieving working Plasma Desktop on Guix?
>>
>> Maxim - I was able to only find your email address; I don't think the
>> other participants of this Debbugs issue will receive a copy of this
>> message.
>>
>> Best Regards,
>> Marek Paśnikowski
>>
>> [1]: https://doc.qt.io/qt-6.2/deployment-plugins.html#loading-and-verifying-plugins-dynamically
>
> The upstream bug I had opened,
> https://bugreports.qt.io/browse/QTBUG-107459, has now been closed as
> "Believed not to be a problem.", so it's indeed supposed to work.
>
> I'll try looking into reverting some of the changes made when Qt 6 was
> introduced; there may be warnings, if I recall correctly, but since it's
> advertised as something supported, let's put it to the test!

So I finally tried it in guix/build/qt-utils.scm:

--8<---------------cut here---------------start------------->8---
@@ -87,9 +88,7 @@ (define exists? (match file-type
       "/applications" "/cursors" "/fonts" "/icons" "/glib-2.0/schemas"
       "/mime" "/sounds" "/themes" "/wallpapers")
     '("XDG_CONFIG_DIRS" suffix directory "/etc/xdg")
-    ;; We wrap exactly to avoid potentially mixing Qt5/Qt6 components, which
-    ;; would cause warnings, perhaps problems.
-    `("QT_PLUGIN_PATH" = directory
+    `("QT_PLUGIN_PATH" prefix directory
       ,(format #f "/lib/qt~a/plugins" qt-major-version))
     `("QML2_IMPORT_PATH" = directory
       ,(format #f "/lib/qt~a/qml" qt-major-version))
--8<---------------cut here---------------end--------------->8---

And I see, as I had originally found:

--8<---------------cut here---------------start------------->8---
$ ./pre-inst-env guix shell --pure qtwayland@5 qtbase@5 jami 

[...]

[env]$ echo $QT_PLUGIN_PATH 
/gnu/store/06r23gkwlkzgivf411sk231sbvy5ghcm-profile/lib/qt5/plugins
maxim@hurd ~/src/guix [env]$ jami   
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/platforms/libqeglfs.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/platforms/libqlinuxfb.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/platforms/libqminimal.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/platforms/libqminimalegl.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/platforms/libqoffscreen.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/platforms/libqvnc.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/rpn3knqgk81c27va7bxrpayv0dv5s4kr-qtwayland-5.15.8/lib/qt5/plugins/platforms/libqwayland-egl.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/rpn3knqgk81c27va7bxrpayv0dv5s4kr-qtwayland-5.15.8/lib/qt5/plugins/platforms/libqwayland-generic.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/rpn3knqgk81c27va7bxrpayv0dv5s4kr-qtwayland-5.15.8/lib/qt5/plugins/platforms/libqwayland-xcomposite-egl.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/rpn3knqgk81c27va7bxrpayv0dv5s4kr-qtwayland-5.15.8/lib/qt5/plugins/platforms/libqwayland-xcomposite-glx.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/platforms/libqxcb.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-maxim'
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/platformthemes/libqgtk3.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/platformthemes/libqxdgdesktopportal.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/platforminputcontexts/libcomposeplatforminputcontextplugin.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/platforminputcontexts/libibusplatforminputcontextplugin.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
Using Qt runtime version: 6.3.2

(jami:9326): libnotify-WARNING **: 19:41:03.309: Failed to connect to proxy
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/imageformats/libqgif.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/imageformats/libqico.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/imageformats/libqjpeg.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
"Using locale: C"
19:41:03.438         os_core_unix.c !pjlib 2.12.1 for POSIX initialized
Daemon is running
No migration required
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/sqldrivers/libqsqlite.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/sqldrivers/libqsqlmysql.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/sqldrivers/libqsqlodbc.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/sqldrivers/libqsqlpsql.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
Syncing lrc accounts list with the daemon
Cannot find dbus interface for screen saver
qt.core.qobject.connect: QObject::connect(lrc::api::ContactModel, ContactAdapter): unique connections require a pointer to member function of a QObject subclass
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/xcbglintegrations/libqxcb-egl-integration.so:
  Plugin uses incompatible Qt library (5.15.0) [release]
qt.core.plugin.loader: In /gnu/store/047ay09ng8kvvbk2h51hbm5mf7x4garg-qtbase-5.15.8/lib/qt5/plugins/xcbglintegrations/libqxcb-glx-integration.so:
  Plugin uses incompatible Qt library (5.15.0) [release]

[...]
--8<---------------cut here---------------end--------------->8---

But Jami runs fine anyway, so I guess it's noise we'll have to put up
with.  I'm merging this change and others to the staging branch now, if
you want to try it out in a day or two it should be fully built for
x86_64.

-- 
Thanks,
Maxim