CMake: Allow using single config generators after building with NMC

Where NMC is the CMake Ninja Multi-Config generator.

The first use case is to allow building standalone tests with one
configuration even if Qt was build with multiple configurations.

Another use case is for regular Qt consumers that might use the
generated qt-cmake shell script which does not have the generator
specified (as opposed to qt-cmake-private).

Another detail is to use the first configuration from the initial
Qt configurations list (CMAKE_CONFIGURATION_TYPES) when building
standalone tests with a single config generator, so that it doesn't
default to Debug, but rather to the provided first configuration.

This matches qmake behavior, where on Windows with a
debug_and_release configuration, tests are still built against
release.

Task-number: QTBUG-80900
Change-Id: I0da91c1f91095332cfe9e38d17f440aad6a09d15
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

1 files changed, 46 insertions, 9 deletions

diff --git a/cmake/QtPostProcess.cmake b/cmake/QtPostProcess.cmake
index a99661f692..6d3c4cd240 100644
--- a/cmake/QtPostProcess.cmake
+++ b/cmake/QtPostProcess.cmake
@@ -323,6 +323,19 @@ function(qt_generate_install_prefixes out_var)
     set(${out_var} "${content}" PARENT_SCOPE)
 endfunction()
 
+function(qt_wrap_string_in_if_multi_config content out_var)
+    set(${out_var} "
+get_property(__qt_is_multi_config GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
+if(__qt_is_multi_config)
+${content}endif()
+unset(__qt_is_multi_config)\n" PARENT_SCOPE)
+endfunction()
+
+function(qt_wrap_string_in_if_ninja_multi_config content out_var)
+    set(${out_var} "if(CMAKE_GENERATOR STREQUAL \"Ninja Multi-Config\")
+${content}endif()\n" PARENT_SCOPE)
+endfunction()
+
 function(qt_generate_build_internals_extra_cmake_code)
     if(PROJECT_NAME STREQUAL "QtBase")
         foreach(var IN LISTS QT_BASE_CONFIGURE_TESTS_VARS_TO_EXPORT)
@@ -343,25 +356,49 @@ function(qt_generate_build_internals_extra_cmake_code)
 
         endif()
         if(CMAKE_CONFIGURATION_TYPES)
-            string(APPEND QT_EXTRA_BUILD_INTERNALS_VARS
-                "set(CMAKE_CONFIGURATION_TYPES \"${CMAKE_CONFIGURATION_TYPES}\" CACHE STRING \"\" FORCE)\n")
+            string(APPEND multi_config_specific
+                "    set(CMAKE_CONFIGURATION_TYPES \"${CMAKE_CONFIGURATION_TYPES}\" CACHE STRING \"\" FORCE)\n")
         endif()
         if(CMAKE_TRY_COMPILE_CONFIGURATION)
-            string(APPEND QT_EXTRA_BUILD_INTERNALS_VARS
-                "set(CMAKE_TRY_COMPILE_CONFIGURATION \"${CMAKE_TRY_COMPILE_CONFIGURATION}\")\n")
+            string(APPEND multi_config_specific
+                "    set(CMAKE_TRY_COMPILE_CONFIGURATION \"${CMAKE_TRY_COMPILE_CONFIGURATION}\")\n")
+        endif()
+        if(multi_config_specific)
+            qt_wrap_string_in_if_multi_config(
+                "${multi_config_specific}"
+                multi_config_specific)
+            string(APPEND QT_EXTRA_BUILD_INTERNALS_VARS "${multi_config_specific}")
         endif()
+
         if(QT_MULTI_CONFIG_FIRST_CONFIG)
             string(APPEND QT_EXTRA_BUILD_INTERNALS_VARS
-                "set(QT_MULTI_CONFIG_FIRST_CONFIG \"${QT_MULTI_CONFIG_FIRST_CONFIG}\")\n")
+                "\nset(QT_MULTI_CONFIG_FIRST_CONFIG \"${QT_MULTI_CONFIG_FIRST_CONFIG}\")\n")
+        endif()
+        # When building standalone tests against a multi-config Qt, we want to choose the first
+        # configuration, rather than default to Debug.
+        if(multi_config_specific)
+            string(APPEND QT_EXTRA_BUILD_INTERNALS_VARS "
+if(QT_BUILD_STANDALONE_TESTS)
+    set(CMAKE_BUILD_TYPE \"\${QT_MULTI_CONFIG_FIRST_CONFIG}\" CACHE STRING \"Choose the type of build.\" FORCE)
+endif()\n")
+            string(APPEND QT_EXTRA_BUILD_INTERNALS_VARS "${multi_config_specific}")
         endif()
+
         if(CMAKE_CROSS_CONFIGS)
-            string(APPEND QT_EXTRA_BUILD_INTERNALS_VARS
-                "set(CMAKE_CROSS_CONFIGS \"${CMAKE_CROSS_CONFIGS}\" CACHE STRING \"\")\n")
+            string(APPEND ninja_multi_config_specific
+                "    set(CMAKE_CROSS_CONFIGS \"${CMAKE_CROSS_CONFIGS}\" CACHE STRING \"\")\n")
         endif()
         if(CMAKE_DEFAULT_BUILD_TYPE)
-            string(APPEND QT_EXTRA_BUILD_INTERNALS_VARS
-                "set(CMAKE_DEFAULT_BUILD_TYPE \"${CMAKE_DEFAULT_BUILD_TYPE}\" CACHE STRING \"\")\n")
+            string(APPEND ninja_multi_config_specific
+                "    set(CMAKE_DEFAULT_BUILD_TYPE \"${CMAKE_DEFAULT_BUILD_TYPE}\" CACHE STRING \"\")\n")
+        endif()
+        if(ninja_multi_config_specific)
+            qt_wrap_string_in_if_ninja_multi_config(
+                "${ninja_multi_config_specific}"
+                ninja_multi_config_specific)
+            string(APPEND QT_EXTRA_BUILD_INTERNALS_VARS "${ninja_multi_config_specific}")
         endif()
+
         if(DEFINED BUILD_WITH_PCH)
             string(APPEND QT_EXTRA_BUILD_INTERNALS_VARS
                 "set(BUILD_WITH_PCH \"${BUILD_WITH_PCH}\" CACHE STRING \"\")\n")