Details
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Task
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Resolution: Unresolved
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P3: Somewhat important
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None
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6.2.0 Beta2
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None
Description
This issue is mostly to keep a place for the result of my investigation on how REQUIRED should affect package components.
In the qt 5.15 CMake integration, the Umbrella Qt5Config.cmake file passed REQUIRED option to the find_package components call here
https://github.com/qt/qtbase/blob/5.15.2/src/corelib/Qt5Config.cmake.in#L30
In Qt 6.0-6.2-beta2, we do not pass it.
https://github.com/qt/qtbase/blob/e933d71a610a951cc6af3c2ac40b97037a14bf9c/cmake/QtConfig.cmake.in#L102
The variable is always expanded to an empty string, because it's not set. It was likely an oversight when porting the code.
It's still a bit unclear to me, but I tend to think we should NOT pass REQUIRED to the component find_package calls, because I would expect that the umbrella project Config file should get the final say on whether a component is required. It also affects the error messages shown.
There is also some inconsistency in how CMake itself handles COMPONENTS vs REQUIRED COMPONENTS signature. https://gitlab.kitware.com/cmake/cmake/-/issues/22513
The following are the error messages shown with https://codereview.qt-project.org/c/qt/qtbase/+/362871 and REQUIRED not passed to the component find_package calls.
find_package(Qt6 QUIET REQUIRED COMPONENTS OpenGL) # Qt6OpenGL_FOUND is set to FALSE manually
CMake Error at /Volumes/T3/Dev/qt/qt5_cmake/worktrees/dev/qtbase/examples/widgets/painting/shared/use_lib.cmake:10 (find_package): Found package configuration file: /Volumes/T3/Dev/qt/qt5_cmake/builds/dev-mac/qtbase/lib/cmake/Qt6/Qt6Config.cmake but it set Qt6_FOUND to FALSE so package "Qt6" is considered to be NOT FOUND. Reason given by package: Failed to find Qt component "OpenGL". Expected Config file at "/Volumes/T3/Dev/qt/qt5_cmake/builds/dev-mac/qtbase/lib/cmake/Qt6OpenGL/Qt6OpenGLConfig.cmake" exists
find_package(Qt6 QUIET REQUIRED COMPONENTS NonExistent)
CMake Error at /Volumes/T3/Dev/qt/qt5_cmake/worktrees/dev/qtbase/examples/widgets/painting/shared/use_lib.cmake:10 (find_package): Found package configuration file: /Volumes/T3/Dev/qt/qt5_cmake/builds/dev-mac/qtbase/lib/cmake/Qt6/Qt6Config.cmake but it set Qt6_FOUND to FALSE so package "Qt6" is considered to be NOT FOUND. Reason given by package: Failed to find Qt component "NonExistent". Expected Config file at "/Volumes/T3/Dev/qt/qt5_cmake/builds/dev-mac/qtbase/lib/cmake/Qt6NonExistent/Qt6NonExistentConfig.cmake" does NOT exist
The following are the error messages shown with https://codereview.qt-project.org/c/qt/qtbase/+/362871 and REQUIRED passed to the component find_package calls.
find_package(Qt6 QUIET REQUIRED COMPONENTS OpenGL) # Qt6OpenGL_FOUND is set to FALSE manually
CMake Error at /Volumes/T3/Dev/qt/qt5_cmake/builds/dev-mac/qtbase/lib/cmake/Qt6/Qt6Config.cmake:134 (find_package): Found package configuration file: /Volumes/T3/Dev/qt/qt5_cmake/builds/dev-mac/qtbase/lib/cmake/Qt6OpenGL/Qt6OpenGLConfig.cmake but it set Qt6OpenGL_FOUND to FALSE so package "Qt6OpenGL" is considered to be NOT FOUND.
find_package(Qt6 QUIET REQUIRED COMPONENTS NonExistent)
CMake Error at /Volumes/T3/Dev/qt/qt5_cmake/builds/dev-mac/qtbase/lib/cmake/Qt6/Qt6Config.cmake:134 (find_package): Could not find a package configuration file provided by "Qt6NonExistent" with any of the following names: Qt6NonExistentConfig.cmake qt6nonexistent-config.cmake Add the installation prefix of "Qt6NonExistent" to CMAKE_PREFIX_PATH or set "Qt6NonExistent_DIR" to a directory containing one of the above files. If "Qt6NonExistent" provides a separate development package or SDK, be sure it has been installed.
I'm undecided which of the error messages are more informational and would better serve users, but i'll probably keep the error messages where REQUIRED is not passed to the component find_package calls.
Attachments
Issue Links
- relates to
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QTBUG-95532 Can't build qtquickcalendar due to missing SQL dependency
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- Closed
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