Bug#1147660: kde-spectacle: FTBFS with OpenCV 5.0

[Aron Xu]

Source: kde-spectacle
Version: 4:6.7.4-1
Severity: important
Tags: ftbfs
User: opencv at packages.debian.org
Usertags: opencv5-transition
Control: affects -1 src:opencv
X-Debbugs-Cc: opencv at packages.debian.org, aron at debian.org

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 kde-spectacle's case, CMakeLists.txt:94 calls find_package(OpenCV 4.7)
(or similarly pins a 4.x floor), and CMake's config-mode search rejects
the only OpenCV package present, /usr/lib/x86_64-linux-gnu/cmake/opencv5/
OpenCVConfig.cmake, because it reports version 5.0.0, which does not
satisfy the requested "4.7" constraint. The log shows this is a plain
version mismatch, not a missing package or a moved component: OpenCV is
found, just refused on version grounds. The maintainer should update
CMakeLists.txt:94 to accept OpenCV 5 (e.g. find_package(OpenCV 5) or a
version range covering 4.7..<6), and audit the OpenCV modules the
project actually links against for the calib3d/features2d renames noted
above.

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.

  -- Performing Test HAVE_STDATOMIC - Success
  -- Found WrapAtomic: TRUE
  -- Found OpenGL: /usr/lib/x86_64-linux-gnu/libOpenGL.so
  -- Found WrapOpenGL: TRUE
  -- Found WrapVulkanHeaders: /usr/include
  -- Could NOT find Cups (missing: CUPS_LIBRARIES CUPS_INCLUDE_DIR)
  -- Found Wayland_Client:
/usr/lib/x86_64-linux-gnu/libwayland-client.so (found version
"1.26.0")
  -- Found Wayland_Server:
/usr/lib/x86_64-linux-gnu/libwayland-server.so (found version
"1.26.0")
  -- Found Wayland_Cursor:
/usr/lib/x86_64-linux-gnu/libwayland-cursor.so (found version
"1.26.0")
  -- Found Wayland_Egl: /usr/lib/x86_64-linux-gnu/libwayland-egl.so
(found version "18.1.0")
  -- Found Wayland:
/usr/lib/x86_64-linux-gnu/libwayland-client.so;/usr/lib/x86_64-linux-gnu/libwayland-server.so;/usr/lib/x86_64-linux-gnu/libwayland-cursor.so;/usr/lib/x86_64-linux-gnu/libwayland-egl.so
(found version "1.26.0")
  -- Found WaylandScanner: /usr/bin/wayland-scanner
  -- Found XKB: /usr/lib/x86_64-linux-gnu/libxkbcommon.so (found
suitable version "1.13.1", minimum required is "0.9.0")
  -- Found KF6CoreAddons:
/usr/lib/x86_64-linux-gnu/cmake/KF6CoreAddons/KF6CoreAddonsConfig.cmake
(found version "6.28.0")
  -- Found KF6WidgetsAddons:
/usr/lib/x86_64-linux-gnu/cmake/KF6WidgetsAddons/KF6WidgetsAddonsConfig.cmake
(found version "6.28.0")
  -- Found KF6DBusAddons:
/usr/lib/x86_64-linux-gnu/cmake/KF6DBusAddons/KF6DBusAddonsConfig.cmake
(found version "6.28.0")
  -- Found KF6Notifications:
/usr/lib/x86_64-linux-gnu/cmake/KF6Notifications/KF6NotificationsConfig.cmake
(found version "6.28.0")
  -- Found KF6Config:
/usr/lib/x86_64-linux-gnu/cmake/KF6Config/KF6ConfigConfig.cmake (found
version "6.28.0")
  -- Found Gettext: /usr/bin/msgmerge (found version "1.0")
  -- Found KF6I18n:
/usr/lib/x86_64-linux-gnu/cmake/KF6I18n/KF6I18nConfig.cmake (found
version "6.28.0")
  -- Found X11: /usr/include
  -- Looking for XOpenDisplay in /usr/lib/x86_64-linux-gnu/libX11.so
  -- Looking for XOpenDisplay in /usr/lib/x86_64-linux-gnu/libX11.so - found
  -- Looking for gethostbyname
  -- Looking for gethostbyname - found
  -- Looking for connect
  -- Looking for connect - found
  -- Looking for remove
  -- Looking for remove - found
  -- Looking for shmat
  -- Looking for shmat - found
  -- Found KF6KIO:
/usr/lib/x86_64-linux-gnu/cmake/KF6KIO/KF6KIOConfig.cmake (found
version "6.28.0")
  -- Found KF6WindowSystem:
/usr/lib/x86_64-linux-gnu/cmake/KF6WindowSystem/KF6WindowSystemConfig.cmake
(found version "6.28.0")
  -- Found KF6GlobalAccel:
/usr/lib/x86_64-linux-gnu/cmake/KF6GlobalAccel/KF6GlobalAccelConfig.cmake
(found version "6.28.0")
  -- Found KF6XmlGui:
/usr/lib/x86_64-linux-gnu/cmake/KF6XmlGui/KF6XmlGuiConfig.cmake (found
version "6.28.0")
  -- Found KF6GuiAddons:
/usr/lib/x86_64-linux-gnu/cmake/KF6GuiAddons/KF6GuiAddonsConfig.cmake
(found version "6.28.0")
  -- Found KF6KirigamiPlatform:
/usr/lib/x86_64-linux-gnu/cmake/KF6KirigamiPlatform/KF6KirigamiPlatformConfig.cmake
(found version "6.28.0")
  -- Found KF6StatusNotifierItem:
/usr/lib/x86_64-linux-gnu/cmake/KF6StatusNotifierItem/KF6StatusNotifierItemConfig.cmake
(found version "6.28.0")
  -- Found KF6Prison:
/usr/lib/x86_64-linux-gnu/cmake/KF6Prison/KF6PrisonConfig.cmake (found
version "6.28.0")
  -- Found KF6Crash:
/usr/lib/x86_64-linux-gnu/cmake/KF6Crash/KF6CrashConfig.cmake (found
version "6.28.0")
  -- Found KF6: success (found suitable version "6.28.0", minimum
required is "6.26.0") found components: CoreAddons WidgetsAddons
DBusAddons Notifications Config I18n KIO WindowSystem GlobalAccel
XmlGui GuiAddons KirigamiPlatform StatusNotifierItem Prison Crash
  -- Found Wayland:
/usr/lib/x86_64-linux-gnu/libwayland-client.so;/usr/lib/x86_64-linux-gnu/libwayland-server.so;/usr/lib/x86_64-linux-gnu/libwayland-cursor.so;/usr/lib/x86_64-linux-gnu/libwayland-egl.so
(found version "1.26.0") found components: Client
  CMake Error at CMakeLists.txt:94 (find_package):
    Could not find a configuration file for package "OpenCV" that is compatible
    with requested version "4.7".

    The following configuration files were considered but not accepted:

      /usr/lib/x86_64-linux-gnu/cmake/opencv5/OpenCVConfig.cmake, version: 5.0.0
        The version found is not compatible with the version requested.
      /lib/x86_64-linux-gnu/cmake/opencv5/OpenCVConfig.cmake, version: 5.0.0
        The version found is not compatible with the version requested.



  -- Configuring incomplete, errors occurred!

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

Thanks,
Aron
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