Dear maintainer,

Your package fails to build from source against opencv 5.0.0+dfsg-1~exp1,
currently in experimental.

OpenCV 5.0 renames its entire install tree from opencv4 to opencv5 and ships
no compatibility shims:

  * pkg-config: only /usr/lib/<triplet>/pkgconfig/opencv5.pc.  There is no
                opencv4.pc and no opencv.pc.
  * headers:    /usr/include/opencv5/opencv2/..., no /usr/include/opencv4.
  * cmake:      /usr/lib/<triplet>/cmake/opencv5/OpenCVConfig.cmake.  A bare
                find_package(OpenCV) still resolves, but a pinned version
                such as find_package(OpenCV 4.7) no longer matches.
  * modules:    libopencv-calib3d-dev is split into libopencv-calib-dev,
                libopencv-geometry-dev, libopencv-stereo-dev and
                libopencv-ptcloud-dev; libopencv-features2d-dev becomes
                libopencv-features-dev.  The CMake component names change
                with them (features2d -> features).
  * geometry:   the new geometry module is not only a piece of calib3d.  It
                also absorbs shape and contour functions that used to live
                in imgproc -- contourArea, arcLength, approxPolyDP,
                boundingRect, minAreaRect, convexHull and
                getPerspectiveTransform among them -- and opencv2/opencv.hpp
                does not pull in opencv2/geometry.hpp, so code that reached
                those through the umbrella header now needs an explicit
                include of opencv2/geometry.hpp.

In ukui-biometric-manager's case, the qmake build fails during
dh_auto_configure (debian/rules:13) because the project's .pro file
checks for the "opencv4" pkg-config module before any compilation
starts, and that module no longer exists under OpenCV 5. qmake
reports "Project ERROR: opencv4 development package not found" and
exits, which make turns into "Error 25", and dpkg-buildpackage aborts
the whole binary target. The maintainer should update the .pro file's
package check (and any PKGCONFIG += opencv4 entry) to opencv5 so
qmake queries the new opencv5.pc instead. The build never reaches the
compile step, so this log does not show whether any hardcoded
/usr/include/opencv4 paths also need updating.

The same source builds fine in the same chroot against the OpenCV 4.10
packages currently in unstable, so this is specific to OpenCV 5.

The relevant part of the build log follows; the full log is attached.


  make[1]: Leaving directory
'/build/reproducible-path/ukui-biometric-manager-1.0.3.1'
     dh_clean
   debian/rules binary
  dh binary
  dh: warning: Implicitly activating single-binary dh addon for
backwards compatibility.  In compat 14+,
  dh: warning: this fallback will *not* happen automatically via
dh_auto_install will instead use a
  dh: warning: different default for --destdir unless the
single-binary add-on is active,
  dh: warning: which can cause the source to produce an empty binary package
  dh: warning:
  dh: warning: To keep the existing behaviour (compat 13), please
activate the single-binary addon explicitly.
  dh: warning: This can be done by adding "dh-sequence-single-binary"
to Build-Depends or passing
  dh: warning: --with=single-binary to dh.
  dh: warning:
  dh: warning: If you have solved this issue differently (e.g., by
passing --destdir explicitly to
  dh: warning: dh_auto_install or not using dh_auto_install at all)
and want to silence this warning
  dh: warning: without activating the addon, you can do that by
passing --without=single-binary to dh
  dh: warning: to explicitly acknowledge the change.
  dh: warning:
  dh: warning: Please see the description of the "single-binary" in
"man dh" for more details of what
  dh: warning: it does and why this is changing from implicit
behaviour to explicitly opt-in.
     dh_update_autotools_config
     dh_autoreconf
     dh_auto_configure
  Info: creating stash file
/build/reproducible-path/ukui-biometric-manager-1.0.3.1/.qmake.stash
  Updating 'i18n_ts/bo.qm'...
      Generated 0 translation(s) (0 finished and 0 unfinished)
      Ignored 141 untranslated source text(s)
  Updating 'i18n_ts/es.qm'...
      Generated 123 translation(s) (118 finished and 5 unfinished)
      Ignored 18 untranslated source text(s)
  Updating 'i18n_ts/fr.qm'...
      Generated 123 translation(s) (118 finished and 5 unfinished)
      Ignored 18 untranslated source text(s)
  Updating 'i18n_ts/pt.qm'...
      Generated 123 translation(s) (118 finished and 5 unfinished)
      Ignored 18 untranslated source text(s)
  Updating 'i18n_ts/ru.qm'...
      Generated 123 translation(s) (118 finished and 5 unfinished)
      Ignored 18 untranslated source text(s)
  Updating 'i18n_ts/tr.qm'...
      Generated 126 translation(s) (124 finished and 2 unfinished)
      Ignored 15 untranslated source text(s)
  Updating 'i18n_ts/zh_CN.qm'...
      Generated 140 translation(s) (140 finished and 0 unfinished)
      Ignored 1 untranslated source text(s)
  Project ERROR: opencv4 development package not found
  make: *** [debian/rules:13: binary] Error 25
  dpkg-buildpackage: error: debian/rules binary subprocess failed with
exit status 2
  --------------------------------------------------------------------------------

Please close this bug if it turns out to be a collision with another ongoing
transition rather than an OpenCV 5 problem.

Thanks,
Aron