[Bug 1950959] Re: [SRU] Missing dependency in libqt5gstreamer-dev

[Simon Quigley]

The code looks good, sponsoring with a minor nitpicky version tweak.
I'll let the SRU team decide further.

** Changed in: qtcreator (Ubuntu Focal)
       Status: Confirmed => In Progress

** Changed in: qtcreator (Ubuntu Jammy)
       Status: Confirmed => In Progress

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Title:
  [SRU] Missing dependency in libqt5gstreamer-dev

Status in qtcreator package in Ubuntu:
  Fix Released
Status in qtcreator source package in Focal:
  In Progress
Status in qtcreator source package in Jammy:
  In Progress
Status in qt-gstreamer package in Debian:
  Fix Released

Bug description:
  [ Impact ]

  The package libqt5gstreamer-dev is mostly unusable for users whose development environment uses pkg-config to find dependencies.
  If we use pkg-config to find the CFLAGS that are needed to link with libQt5GStreamer-1.0.so then that will fail.

  An example command:

  # pkg-config --cflags Qt5GStreamer-1.0
  Package gobject-2.0 was not found in the pkg-config search path.
  Perhaps you should add the directory containing `gobject-2.0.pc'
  to the PKG_CONFIG_PATH environment variable
  Package 'gobject-2.0', required by 'Qt5GLib-2.0', not found

  [ Test Plan ]

   * Execute the command "pkg-config --cflags Qt5GStreamer-1.0" and
  cofirm that pkg-config can find the CFLAGS needed to link with
  libQt5GStreamer-1.0.so

  [ Where problems could occur ]

   * The dependency fix alone should not cause any problem as its not
  changing any part of the code. But another fix from Debian had to be
  added, as without that fix the package is failing to build in Jammy.
  And, this patch is removing a volatile qualifier from a variable. But
  this patch is in Debian since Sept, 2022 without any report of
  regression so I will assume there is little chance of regression on
  adding it here in Jammy.

   * Apart from the dependency fix, another patch had to be added for
  Focal as it was failing to build. This patch is in Debian since
  Feb,2021 with no report of regression and has also been applied
  upstream, there is little chance of regression from this patch.

  [ Other Info ]

   * the package mentioned in the bug is wrong, it affects qt-gstreamer
  source.

   * as mentioned above an extra Debian patch is needed. Without that
  patch the build fails in Jammy with the error:

  /<<PKGBUILDDIR>>/elements/gstqtvideosink/gstqwidgetvideosink.cpp: In static member function ‘static GType GstQWidgetVideoSink::get_type()’:
  /usr/include/glib-2.0/glib/gatomic.h:113:19: error: argument 2 of ‘__atomic_load’ must not be a pointer to a ‘volatile’ type
    113 |     __atomic_load (gapg_temp_atomic, &gapg_temp_newval, __ATOMIC_SEQ_CST); \
        |     ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /usr/include/glib-2.0/glib/gthread.h:260:7: note: in expansion of macro ‘g_atomic_pointer_get’
    260 |     (!g_atomic_pointer_get (location) &&                             \
        |       ^~~~~~~~~~~~~~~~~~~~
  /<<PKGBUILDDIR>>/elements/gstqtvideosink/gstqtvideosinkplugin.h:31:13: note: in expansion of macro ‘g_once_init_enter’
     31 |         if (g_once_init_enter(&gonce_data)) { \
        |             ^~~~~~~~~~~~~~~~~
  /<<PKGBUILDDIR>>/elements/gstqtvideosink/gstqtvideosinkplugin.h:56:5: note: in expansion of macro ‘DEFINE_TYPE_FULL’
     56 |     DEFINE_TYPE_FULL(cpp_type, #cpp_type "_qt5", parent_type, Q_UNUSED)
        |     ^~~~~~~~~~~~~~~~
  /<<PKGBUILDDIR>>/elements/gstqtvideosink/gstqwidgetvideosink.cpp:22:1: note: in expansion of macro ‘DEFINE_TYPE’
     22 | DEFINE_TYPE(GstQWidgetVideoSink, GST_TYPE_QT_VIDEO_SINK_BASE)
        | ^~~~~~~~~~~
  make[4]: *** [elements/gstqtvideosink/CMakeFiles/gstqt5videosink.dir/build.make:227: elements/gstqtvideosink/CMakeFiles/gstqt5videosink.dir/gstqwidgetvideosink.cpp.o] Error 1

  * The package failed to build in Focal also and a Debian patch had to
  be added for that.

  * The problem has been fixed in Debian with qt-gstreamer_1.2.0-5.2, so
  Lunar, Mantic and Noble are not affected. Only Jammy and Focal are
  affected.

  [ Original Bug Description ]

  After installing libqt5gstreamer-dev, the following command fails:

  pkg-config --exists Qt5GStreamer-1.0 || echo "Failed"
  Failed

  more info:
  pkg-config --cflags Qt5GStreamer-1.0
  Package gstreamer-1.0 was not found in the pkg-config search path.
  Perhaps you should add the directory containing `gstreamer-1.0.pc'
  to the PKG_CONFIG_PATH environment variable
  Package 'gstreamer-1.0', required by 'Qt5GStreamer-1.0', not found

  After installing libgstreamer-plugins-base1.0-dev (also brings the
  missing libgstreamer1.0-dev), it works.

  * Ubuntu 20.04.3 LTS
  * libqt5gstreamer-dev (1.2.0-5)
  * amd64

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