[MacPorts] #48288: CMake generating broken Xcode projects when using OpenCV

[MacPorts]

#48288: CMake generating broken Xcode projects when using OpenCV
-----------------------------------+--------------------------------
  Reporter:  christian.richardt@…  |      Owner:  macports-tickets@…
      Type:  defect                |     Status:  new
  Priority:  Normal                |  Milestone:
 Component:  ports                 |    Version:  2.3.3
Resolution:                        |   Keywords:
      Port:  opencv cmake          |
-----------------------------------+--------------------------------

Comment (by christian.richardt@…):

 The problem in `FRAMEWORK_SEARCH_PATHS = (//System/Library/Frameworks, );`
 indeed appears to be the double slash. Deleting one of the slashes
 manually (in all instances) fixes the Xcode project. Seems like Xcode is a
 little fragile in that respect, and maybe it's a a regression in Xcode.

 I narrowed it down to the `qt4` variant that adds the double slash in
 OpenCV:
 {{{
 $ diff -c OpenCVModules-release\@3.0.0_0.cmake OpenCVModules-
 release\@3.0.0_0+qt4.cmake
 *** OpenCVModules-release at 3.0.0_0.cmake 2015-06-22 21:27:25.000000000
 +0200
 --- OpenCVModules-release at 3.0.0_0+qt4.cmake     2015-07-09
 23:47:38.000000000 +0200
 ***************
 *** 9,14 ****
 --- 9,15 ----
   set_property(TARGET opencv_hal APPEND PROPERTY IMPORTED_CONFIGURATIONS
 RELEASE)
   set_target_properties(opencv_hal PROPERTIES
     IMPORTED_LINK_INTERFACE_LANGUAGES_RELEASE "CXX"
 +   IMPORTED_LINK_INTERFACE_LIBRARIES_RELEASE
 "//System/Library/Frameworks/AGL.framework;//System/Library/Frameworks/OpenGL.framework"
     IMPORTED_LOCATION_RELEASE "${_IMPORT_PREFIX}/lib/libopencv_hal.a"
     )

 ***************
 *** 154,160 ****
   set_property(TARGET opencv_ts APPEND PROPERTY IMPORTED_CONFIGURATIONS
 RELEASE)
   set_target_properties(opencv_ts PROPERTIES
     IMPORTED_LINK_INTERFACE_LANGUAGES_RELEASE "CXX"
 !   IMPORTED_LINK_INTERFACE_LIBRARIES_RELEASE
 "opencv_hal;opencv_core;opencv_imgproc;opencv_imgcodecs;opencv_videoio;opencv_highgui"
     IMPORTED_LOCATION_RELEASE "${_IMPORT_PREFIX}/lib/libopencv_ts.a"
     )

 --- 155,161 ----
   set_property(TARGET opencv_ts APPEND PROPERTY IMPORTED_CONFIGURATIONS
 RELEASE)
   set_target_properties(opencv_ts PROPERTIES
     IMPORTED_LINK_INTERFACE_LANGUAGES_RELEASE "CXX"
 !   IMPORTED_LINK_INTERFACE_LIBRARIES_RELEASE
 "opencv_hal;opencv_core;opencv_imgproc;opencv_imgcodecs;opencv_videoio;opencv_highgui;//System/Library/Frameworks/AGL.framework;//System/Library/Frameworks/OpenGL.framework"
     IMPORTED_LOCATION_RELEASE "${_IMPORT_PREFIX}/lib/libopencv_ts.a"
     )
 }}}

 {{{
 $ diff opencv\@3.0.0_0.pc opencv\@3.0.0_0+qt4.pc
 13c13
 < Libs.private: -l-framework Cocoa -L/opt/local/lib -lpng -ltiff -ljasper
 -ljpeg -lImath -lIlmImf -lIex -lHalf -lIlmThread -lavcodec -lavformat
 -lavutil -lswscale -lavresample -lz -lbz2 -l-framework
 VideoDecodeAcceleration -l-framework QTKit -l-framework QuartzCore
 -l-framework AppKit
 ---
 > Libs.private: -L/opt/local/lib -lQtOpenGL -lQtGui -lQtTest -lQtCore
 -lpng -ltiff -ljasper -ljpeg -lImath -lIlmImf -lIex -lHalf -lIlmThread
 -lavcodec -lavformat -lavutil -lswscale -lavresample -lz -lbz2
 -l-framework VideoDecodeAcceleration -l-framework QTKit -l-framework
 QuartzCore -l-framework AppKit -L//System/Library/Frameworks -lAGL
 -lOpenGL
 }}}

 I tracked down the source to the following: if OpenCV is configured
 `WITH_QT`, and Qt is found,
 [https://github.com/Itseez/opencv/blob/b46719b0931b256ab68d5f833b8fadd83737ddd1/cmake/OpenCVFindLibsGUI.cmake#L73
 OpenCVFindLibsGUI.cmake] also adds `${OPENGL_LIBRARIES}` (AGL and OpenGL)
 to `OPENCV_LINKER_LIBS`. This appears to be the step that produces the
 broken paths. For some reason, the SDK path component is missing, which I
 do get if I do
 {{{
 find_package(OpenGL REQUIRED)
 message(STATUS ${OPENGL_LIBRARIES})
 }}}
 in a test project:
 {{{
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/AGL.framework
 /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk/System/Library/Frameworks/OpenGL.framework
 }}}

 I don't understand why `find_package(OpenGL REQUIRED)` produces different
 paths when MacPort configures OpenCV than when I use it in my own project?

-- 
Ticket URL: <https://trac.macports.org/ticket/48288#comment:4>
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