CMake: Handle conditions in third party find modules correctly

Previously the FindWrap modules checked for hardcoded features
when deciding whether to use a bundled library or not. This proved
not to work correctly because features were not available when
the find modules were processed.

Introduce a new CMake API call that needs to be manually called
after an add_subdirectory call which declares a bundled library.

The call will check for the existence of the bundled target, and will
then set a cache variable QT_USE_BUNDLED_Bundled<TargetName>.

The same variable is written into a FindWrapFooConfigExtra.cmake file
which will be loaded by the appropriate FindWrap module. The module
can that use that variable to decided whether to link against the
bundled library or the system library.

Change-Id: I75e9a4f4e14d88d4490916a79ad12f1ce57891e0
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

8 files changed, 45 insertions, 37 deletions

diff --git a/cmake/FindWrapFreetype.cmake b/cmake/FindWrapFreetype.cmake
index 3f8317be69..59219df6c2 100644
--- a/cmake/FindWrapFreetype.cmake
+++ b/cmake/FindWrapFreetype.cmake
@@ -1,17 +1,11 @@
 include(QtFindWrapHelper NO_POLICY_SCOPE)
 
-set(_qt_wrap_use_bundled FALSE)
-if(QT_FEATURE_freetype AND NOT QT_FEATURE_system_freetype)
-    set(_qt_wrap_use_bundled TRUE)
-endif()
-
 qt_find_package_system_or_bundled(wrap_freetype
     FRIENDLY_PACKAGE_NAME "Freetype"
     WRAP_PACKAGE_TARGET "WrapFreetype::WrapFreetype"
     WRAP_PACKAGE_FOUND_VAR_NAME "WrapFreetype_FOUND"
-    BUNDLED_PACKAGE_NAME "Qt6BundledFreetype"
-    BUNDLED_PACKAGE_TARGET "Qt6::BundledFreetype"
+    BUNDLED_PACKAGE_NAME "BundledFreetype"
+    BUNDLED_PACKAGE_TARGET "BundledFreetype"
     SYSTEM_PACKAGE_NAME "WrapSystemFreetype"
     SYSTEM_PACKAGE_TARGET "WrapSystemFreetype::WrapSystemFreetype"
-    USE_BUNDLED_PACKAGE "${_qt_wrap_use_bundled}"
 )
diff --git a/cmake/FindWrapHarfbuzz.cmake b/cmake/FindWrapHarfbuzz.cmake
index eac95b669d..a66bb08d89 100644
--- a/cmake/FindWrapHarfbuzz.cmake
+++ b/cmake/FindWrapHarfbuzz.cmake
@@ -1,17 +1,11 @@
 include(QtFindWrapHelper NO_POLICY_SCOPE)
 
-set(_qt_wrap_use_bundled FALSE)
-if(QT_FEATURE_harfbuzz AND NOT QT_FEATURE_system_harfbuzz)
-    set(_qt_wrap_use_bundled TRUE)
-endif()
-
 qt_find_package_system_or_bundled(wrap_harfbuzz
     FRIENDLY_PACKAGE_NAME "Harfbuzz"
     WRAP_PACKAGE_TARGET "WrapHarfbuzz::WrapHarfbuzz"
     WRAP_PACKAGE_FOUND_VAR_NAME "WrapHarfbuzz_FOUND"
-    BUNDLED_PACKAGE_NAME "Qt6BundledHarfbuzz"
-    BUNDLED_PACKAGE_TARGET "Qt6::BundledHarfbuzz"
+    BUNDLED_PACKAGE_NAME "BundledHarfbuzz"
+    BUNDLED_PACKAGE_TARGET "BundledHarfbuzz"
     SYSTEM_PACKAGE_NAME "WrapSystemHarfbuzz"
     SYSTEM_PACKAGE_TARGET "WrapSystemHarfbuzz::WrapSystemHarfbuzz"
-    USE_BUNDLED_PACKAGE "${_qt_wrap_use_bundled}"
 )
diff --git a/cmake/FindWrapPCRE2.cmake b/cmake/FindWrapPCRE2.cmake
index fec46f36b0..08e12163ed 100644
--- a/cmake/FindWrapPCRE2.cmake
+++ b/cmake/FindWrapPCRE2.cmake
@@ -1,17 +1,11 @@
 include(QtFindWrapHelper NO_POLICY_SCOPE)
 
-set(_qt_wrap_use_bundled FALSE)
-if(QT_FEATURE_pcre2 AND NOT QT_FEATURE_system_pcre2)
-    set(_qt_wrap_use_bundled TRUE)
-endif()
-
 qt_find_package_system_or_bundled(wrap_pcre2
     FRIENDLY_PACKAGE_NAME "PCRE2"
     WRAP_PACKAGE_TARGET "WrapPCRE2::WrapPCRE2"
     WRAP_PACKAGE_FOUND_VAR_NAME "WrapPCRE2_FOUND"
-    BUNDLED_PACKAGE_NAME "Qt6BundledPcre2"
-    BUNDLED_PACKAGE_TARGET "Qt6::BundledPcre2"
+    BUNDLED_PACKAGE_NAME "BundledPcre2"
+    BUNDLED_PACKAGE_TARGET "BundledPcre2"
     SYSTEM_PACKAGE_NAME "WrapSystemPCRE2"
     SYSTEM_PACKAGE_TARGET "WrapSystemPCRE2::WrapSystemPCRE2"
-    USE_BUNDLED_PACKAGE "${_qt_wrap_use_bundled}"
 )
diff --git a/cmake/FindWrapPNG.cmake b/cmake/FindWrapPNG.cmake
index d9e7aa539b..55bfbdcffd 100644
--- a/cmake/FindWrapPNG.cmake
+++ b/cmake/FindWrapPNG.cmake
@@ -1,17 +1,11 @@
 include(QtFindWrapHelper NO_POLICY_SCOPE)
 
-set(_qt_wrap_use_bundled FALSE)
-if(QT_FEATURE_png AND NOT QT_FEATURE_system_png)
-    set(_qt_wrap_use_bundled TRUE)
-endif()
-
 qt_find_package_system_or_bundled(wrap_png
     FRIENDLY_PACKAGE_NAME "PNG"
     WRAP_PACKAGE_TARGET "WrapPNG::WrapPNG"
     WRAP_PACKAGE_FOUND_VAR_NAME "WrapPNG_FOUND"
-    BUNDLED_PACKAGE_NAME "Qt6BundledLibpng"
-    BUNDLED_PACKAGE_TARGET "Qt6::BundledLibpng"
+    BUNDLED_PACKAGE_NAME "BundledLibpng"
+    BUNDLED_PACKAGE_TARGET "BundledLibpng"
     SYSTEM_PACKAGE_NAME "WrapSystemPNG"
     SYSTEM_PACKAGE_TARGET "WrapSystemPNG::WrapSystemPNG"
-    USE_BUNDLED_PACKAGE "${_qt_wrap_use_bundled}"
 )
diff --git a/cmake/QtBaseGlobalTargets.cmake b/cmake/QtBaseGlobalTargets.cmake
index 31e0512732..a788392bad 100644
--- a/cmake/QtBaseGlobalTargets.cmake
+++ b/cmake/QtBaseGlobalTargets.cmake
@@ -230,6 +230,7 @@ qt_copy_or_install(FILES
                    cmake/QtCompilerOptimization.cmake
                    cmake/QtFeature.cmake
                    cmake/QtFindWrapHelper.cmake
+                   cmake/QtFindWrapConfigExtra.cmake.in
                    cmake/QtPlatformSupport.cmake
                    cmake/QtPlatformAndroid.cmake
                    cmake/QtPostProcess.cmake
diff --git a/cmake/QtBuild.cmake b/cmake/QtBuild.cmake
index 90306a44c8..e62f5aa196 100644
--- a/cmake/QtBuild.cmake
+++ b/cmake/QtBuild.cmake
@@ -3163,6 +3163,28 @@ function(qt_add_3rdparty_library target)
     endif()
 endfunction()
 
+function(qt_install_3rdparty_library_wrap_config_extra_file target)
+    if(TARGET "${target}")
+        set(use_bundled "ON")
+    else()
+        set(use_bundled "OFF")
+    endif()
+
+    set(QT_USE_BUNDLED_${target} "${use_bundled}" CACHE BOOL "" FORCE)
+    set(extra_cmake_code "set(QT_USE_BUNDLED_${target} ${use_bundled} CACHE BOOL \"\" FORCE)")
+    configure_file(
+        "${QT_CMAKE_DIR}/QtFindWrapConfigExtra.cmake.in"
+        "${QT_CONFIG_BUILD_DIR}/${INSTALL_CMAKE_NAMESPACE}/FindWrap${target}ConfigExtra.cmake"
+         @ONLY
+    )
+
+    qt_install(FILES
+        "${QT_CONFIG_BUILD_DIR}/${INSTALL_CMAKE_NAMESPACE}/FindWrap${target}ConfigExtra.cmake"
+        DESTINATION "${QT_CONFIG_INSTALL_DIR}/${INSTALL_CMAKE_NAMESPACE}"
+        COMPONENT Devel
+    )
+endfunction()
+
 function(qt_get_tool_cmake_configuration out_var)
     qt_get_main_cmake_configuration("${out_var}")
     string(TOUPPER "${${out_var}}" upper_config)
diff --git a/cmake/QtFindWrapConfigExtra.cmake.in b/cmake/QtFindWrapConfigExtra.cmake.in
new file mode 100644
index 0000000000..6ecf43512c
--- /dev/null
+++ b/cmake/QtFindWrapConfigExtra.cmake.in
@@ -0,0 +1 @@
+@extra_cmake_code@
diff --git a/cmake/QtFindWrapHelper.cmake b/cmake/QtFindWrapHelper.cmake
index cb6d19600b..f536df99e1 100644
--- a/cmake/QtFindWrapHelper.cmake
+++ b/cmake/QtFindWrapHelper.cmake
@@ -19,7 +19,6 @@ macro(qt_find_package_system_or_bundled _unique_prefix)
         BUNDLED_PACKAGE_TARGET
         SYSTEM_PACKAGE_NAME
         SYSTEM_PACKAGE_TARGET
-        USE_BUNDLED_PACKAGE
         )
     set(_multioptions "")
 
@@ -36,11 +35,20 @@ macro(qt_find_package_system_or_bundled _unique_prefix)
 
     set(${_qfwrap_${_unique_prefix}_WRAP_PACKAGE_FOUND_VAR_NAME} OFF)
 
-    if(_qfwrap_${_unique_prefix}_USE_BUNDLED_PACKAGE)
+    include("FindWrap${_qfwrap_${_unique_prefix}_BUNDLED_PACKAGE_TARGET}ConfigExtra" OPTIONAL)
+
+    if(NOT DEFINED "QT_USE_BUNDLED_${_qfwrap_${_unique_prefix}_BUNDLED_PACKAGE_TARGET}")
+        message(FATAL_ERROR
+            "Can't find cache variable "
+            "QT_USE_BUNDLED_${_qfwrap_${_unique_prefix}_BUNDLED_PACKAGE_TARGET} "
+            "to decide whether to use bundled or system library.")
+    endif()
+
+    if("${QT_USE_BUNDLED_${_qfwrap_${_unique_prefix}_BUNDLED_PACKAGE_TARGET}}")
         set(${_unique_prefix}_qt_package_name_to_use
-            "${_qfwrap_${_unique_prefix}_BUNDLED_PACKAGE_NAME}")
+            "Qt6${_qfwrap_${_unique_prefix}_BUNDLED_PACKAGE_NAME}")
         set(${_unique_prefix}_qt_package_target_to_use
-            "${_qfwrap_${_unique_prefix}_BUNDLED_PACKAGE_TARGET}")
+            "Qt6::${_qfwrap_${_unique_prefix}_BUNDLED_PACKAGE_TARGET}")
         set(${_unique_prefix}_qt_package_success_message
             "Using Qt bundled ${_qfwrap_${_unique_prefix}_FRIENDLY_PACKAGE_NAME}.")
         set(${_unique_prefix}_qt_package_type "bundled")
@@ -69,6 +77,6 @@ macro(qt_find_package_system_or_bundled _unique_prefix)
                               INTERFACE_QT_3RD_PARTY_PACKAGE_TYPE
                               "${${_unique_prefix}_qt_package_type}")
     elseif(${_unique_prefix}_qt_package_type STREQUAL "bundled")
-        message(FATAL_ERROR "Can't find ${_qfwrap_${_unique_prefix}_BUNDLED_PACKAGE_TARGET}.")
+        message(FATAL_ERROR "Can't find ${${_unique_prefix}_qt_package_target_to_use}.")
     endif()
 endmacro()