Problems with CPack building multiple packages at once - cmake

Question

I'm facing problems using the packaging with CPack and CMake 3.7.2.
I try to build three different packages, MSI (via WIX), IFW, and ZIP.
According to the documentation I set the following variables in my CMakeLists.txt (and a few more which are required):
set(CPACK_WIX_ROOT "C:/Temp/WiX-3.10/binaries")
set(QTIFWDIR "${GLOBAL}/Qt/Tools/QtInstallerFramework/2.0/bin")
set(CPACK_GENERATOR "WIX;IFW;ZIP")
I'm including CPack at the last possible position before any components are defined.
<all variables have been defined before this point>
include(CPack)
include(CPackWIX)
include(CPackIFW)
cpack_add_component(AppBinaries DISPLAY_NAME "MyAppBinaries" DESCRIPTION "My Application Binaries")
cpack_ifw_configure_component(AppBinaries VERSION ${CPACK_PACKAGE_VERSION} SCRIPT "${CMAKE_SOURCE_DIR}/cpack/installscript.qs")
cpack_add_component(AppDocs DISPLAY_NAME "MyAppDocs" DESCRIPTION "My Application Docs")
cpack_add_component(AppData DISPLAY_NAME "MyAppData" DESCRIPTION "My Application Data")
After creating the build dir and running from there
cmake -G "Visual Studio 14 2015 Win64" ..\TestProject
the files CMakeCache.txt, CPackConfig.cmake, CPackSourceConfig.cmake, and CPackProperties.cmake are generated.
When running cpack -C Release to build all three installers at once, the first one (WIX) is built, but the second one (QtIFW) fails with the messages
CPack Error: Cannot find QtIFW compiler "binarycreator": likely it is
not installed, or not in your PATH CPack Error: Cannot initialize the
generator IFW
I inspected the CMakeCache.txt file but found the following entries properly defined:
//QtIFW binarycreator command line client
CPACK_IFW_BINARYCREATOR_EXECUTABLE:FILEPATH=N:/Global/Qt/Tools/QtInstallerFramework/2.0/bin/binarycreator.exe
//QtIFW devtool command line client
CPACK_IFW_DEVTOOL_EXECUTABLE:FILEPATH=N:/Global/Qt/Tools/QtInstallerFramework/2.0/bin/devtool.exe
//QtIFW installer executable base
CPACK_IFW_INSTALLERBASE_EXECUTABLE:FILEPATH=N:/Global/Qt/Tools/QtInstallerFramework/2.0/bin/installerbase.exe
//QtIFW repogen command line client
CPACK_IFW_REPOGEN_EXECUTABLE:FILEPATH=N:/Global/Qt/Tools/QtInstallerFramework/2.0/bin/repogen.exe
//Enable to build 7-Zip source packages
CPACK_SOURCE_7Z:BOOL=ON
//Enable to build ZIP source packages
CPACK_SOURCE_ZIP:BOOL=ON
//Path to a program.
CPACK_WIX_CANDLE_EXECUTABLE:FILEPATH=C:/Temp/WiX-3.10/binaries/candle.exe
//Path to a program.
CPACK_WIX_LIGHT_EXECUTABLE:FILEPATH=C:/Temp/WiX-3.10/binaries/light.exe
But when I checked the CPack\*Config.cmake files none of the entries above are referenced. After running the cmake -G "Visual Studio 14 2015 Win64" ..\TestProject a second time everything is fine; all those entries are referenced in CPack\*Config.cmake files and all three installers can be built.
So I really get stuck at this point.
Any ideas what could be the issue and how to avoid it?

Answer 1

I finally figured out what didn't work as expected. The setting of the QTIFWDIR variable is not saved to the CPack*Config.cmake files, but the CMAKE_WIX_ROOT variable is. Those variables seem to be evaluated at runtime by CPack. Therefore the WIX build run successfully but the IFW build complained about a the missing binarycreator. Adding the variable with its current setting made everything run as expected.
Follow up:
According to the maintainer QTIFWDIR should be rather an environment variable than a CMake variable. And CPACK_WIX_ROOT is considered to be an internal CPack variable. You need to install WIX (and set the WIX environment variable manually, if it hasn't already been done by the installation).