Revert "CMake: Warn if cmake_minimum_required has an unsupported low version"

This reverts commit 657525965b86cfa135bb5a814a537443163acb14.

The change relied on reading the last value of the
CMAKE_MINIMUM_REQUIRED_VERSION variable before one of the Qt packages
is found to use it for the version check.

Even if a user project has a cmake_minimum_required() right at
the beginning of the project with a supported version specified,
the first project() call which loads a CMake toolchain file could
contain another cmake_minimum_required() call with a lower
(unsupported) version and that version would be used for the check,
failing the project configuration.

The Android NDK ships such a toolchain file, which requires version
'3.6'.

Thus, relying on the last value of CMAKE_MINIMUM_REQUIRED_VERSION is
not robust enough.

Pick-to: 6.2
Task-number: QTBUG-95018
Task-number: QTBUG-95832
Change-Id: Iff3cb0a46e6e878569dce9c5fe915a714a034904
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

1 files changed, 0 insertions, 58 deletions

diff --git a/cmake/QtPublicCMakeVersionHelpers.cmake b/cmake/QtPublicCMakeVersionHelpers.cmake
index 638c9edc2d..2b3c697f4c 100644
--- a/cmake/QtPublicCMakeVersionHelpers.cmake
+++ b/cmake/QtPublicCMakeVersionHelpers.cmake
@@ -4,12 +4,6 @@ function(__qt_internal_get_supported_min_cmake_version_for_using_qt out_var)
     set(${out_var} "${supported_version}" PARENT_SCOPE)
 endfunction()
 
-function(__qt_internal_get_supported_min_cmake_version_for_using_qt_in_cmake_min_required out_var)
-    # This is recorded in Qt6ConfigExtras.cmake
-    set(supported_version "${QT_SUPPORTED_MIN_CMAKE_VERSION_FOR_USING_QT_IN_CMAKE_MIN_REQUIRED}")
-    set(${out_var} "${supported_version}" PARENT_SCOPE)
-endfunction()
-
 function(__qt_internal_get_computed_min_cmake_version_for_using_qt out_var)
     # Allow override when configuring user project.
     if(QT_FORCE_MIN_CMAKE_VERSION_FOR_USING_QT)
@@ -26,23 +20,6 @@ function(__qt_internal_get_computed_min_cmake_version_for_using_qt out_var)
     set(${out_var} "${computed_min_version}" PARENT_SCOPE)
 endfunction()
 
-function(__qt_internal_get_computed_min_cmake_version_for_using_qt_in_cmake_min_required out_var)
-    # Allow override when configuring user project.
-    if(QT_FORCE_MIN_CMAKE_VERSION_FOR_USING_QT_IN_CMAKE_MIN_REQUIRED)
-        set(computed_min_version "${QT_FORCE_MIN_CMAKE_VERSION_FOR_USING_QT_IN_CMAKE_MIN_REQUIRED}")
-
-    # Set in QtConfigExtras.cmake.
-    elseif(QT_COMPUTED_MIN_CMAKE_VERSION_FOR_USING_QT_IN_CMAKE_MIN_REQUIRED)
-        set(computed_min_version
-            "${QT_COMPUTED_MIN_CMAKE_VERSION_FOR_USING_QT_IN_CMAKE_MIN_REQUIRED}")
-    else()
-        message(FATAL_ERROR
-            "Qt Developer error: Can't compute the version that should appear in cmake_minimum_required to use this Qt.")
-    endif()
-
-    set(${out_var} "${computed_min_version}" PARENT_SCOPE)
-endfunction()
-
 function(__qt_internal_warn_if_min_cmake_version_not_met)
     __qt_internal_get_supported_min_cmake_version_for_using_qt(min_supported_version)
     __qt_internal_get_computed_min_cmake_version_for_using_qt(computed_min_version)
@@ -57,22 +34,6 @@ function(__qt_internal_warn_if_min_cmake_version_not_met)
     endif()
 endfunction()
 
-function(__qt_internal_warn_if_project_min_cmake_version_is_not_met)
-    __qt_internal_get_supported_min_cmake_version_for_using_qt_in_cmake_min_required(
-        min_supported_version)
-    __qt_internal_get_computed_min_cmake_version_for_using_qt_in_cmake_min_required(
-        computed_min_version)
-
-    if(computed_min_version VERSION_LESS min_supported_version)
-        message(WARNING
-           "To use this Qt, the minimum CMake version that should appear in the project's "
-           "cmake_minimum_required() call should be: '${min_supported_version}'. "
-           "You have explicitly chosen to require a lower version: '${computed_min_version}'. "
-           "Using Qt with this version is not officially supported. Use at your own risk."
-        )
-    endif()
-endfunction()
-
 function(__qt_internal_require_suitable_cmake_version_for_using_qt)
     # Skip the public project check if we're building a Qt repo because it's too early to do
     # it at find_package(Qt6) time.
@@ -105,23 +66,4 @@ function(__qt_internal_require_suitable_cmake_version_for_using_qt)
             "project. Using Qt with this CMake version is not officially supported. "
             "Use at your own risk.")
     endif()
-
-
-    # Check that the project has a supported version specified in the last cmake_minimum_required
-    # call before the Qt6 package was found.
-    __qt_internal_warn_if_project_min_cmake_version_is_not_met()
-    __qt_internal_get_computed_min_cmake_version_for_using_qt_in_cmake_min_required(
-        computed_min_version)
-
-    if(_qt_project_last_cmake_minimum_required_version VERSION_LESS computed_min_version)
-        message(FATAL_ERROR
-            "The last cmake_minimum_required() call before the Qt package was found had the "
-            "following version specified: '${_qt_project_last_cmake_minimum_required_version}' but "
-            "it needs to be ${computed_min_version} or higher to use Qt. "
-            "You can reduce the error into a warning by passing "
-            "-DQT_FORCE_MIN_CMAKE_VERSION_FOR_USING_QT_IN_CMAKE_MIN_REQUIRED=${_qt_project_last_cmake_minimum_required_version} "
-            "when configuring the project, but you do so at your own risk (it is not an officially "
-            "supported way of building Qt projects)."
-        )
-    endif()
 endfunction()