CMake: Deprecate _add_app/executable/test/tool PUBLIC_LIBRARIES option

Warn projects not to use it because PUBLIC_LIBRARIES don't make
sense for executable targets and it also led to some issues in the
internal functions where some of them did not expect to receive
PUBLIC_LIBRARIES.

To ensure builds don't needlessly break, treat PUBLIC_LIBRARIES values
as regular LIBRARIES. In the future we might add an error instead.

Using PUBLIC_LIBRARIES in qt_internal_add_app, etc, accidentally
worked because the option name and the values following it were
parsed as values of the "previous" option, like SOURCES or
INCLUDE_DIRECTORIES or LIBRARIES, and when those got
passed through to qt_internal_extend_target, things magically worked.

We have a lot of projects using PUBLIC_LIBRARIES, mostly due to the
way qmake pro files were written and how pro2cmake converted them.
We'll have to clean up each repo.

Change-Id: I69e09d34afdf98f0d47c08d324643fc986f8131c
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>

cmake/QtAppHelpers.cmake

@@ -5,7 +5,7 @@ function(qt_internal_add_app target)
         "qt_internal_add_app"
         "NO_INSTALL;INSTALL_VERSIONED_LINK;EXCEPTIONS"
         "${__default_target_info_args};INSTALL_DIR"
-        "${__default_private_args}"
+        "${__default_private_args};PUBLIC_LIBRARIES"
         ${ARGN})
 
     set(exceptions "")
@@ -26,6 +26,12 @@ function(qt_internal_add_app target)
         set(no_install NO_INSTALL)
     endif()
 
+    if(arg_PUBLIC_LIBRARIES)
+        message(WARNING
+            "qt_internal_add_app's PUBLIC_LIBRARIES option is deprecated, and will be removed in "
+            "a future Qt version. Use the LIBRARIES option instead.")
+    endif()
+
     qt_internal_add_executable("${target}"
         QT_APP
         DELAY_RC
@@ -39,7 +45,10 @@ function(qt_internal_add_app target)
             ${arg_INCLUDE_DIRECTORIES}
         DEFINES
             ${arg_DEFINES}
-        LIBRARIES ${arg_LIBRARIES} Qt::PlatformAppInternal
+        LIBRARIES
+            ${arg_LIBRARIES}
+            ${arg_PUBLIC_LIBRARIES}
+            Qt::PlatformAppInternal
         COMPILE_OPTIONS ${arg_COMPILE_OPTIONS}
         LINK_OPTIONS ${arg_LINK_OPTIONS}
         MOC_OPTIONS ${arg_MOC_OPTIONS}

cmake/QtExecutableHelpers.cmake

@@ -104,12 +104,21 @@ function(qt_internal_add_executable name)
          ${arg_INCLUDE_DIRECTORIES}
     )
 
+    if(arg_PUBLIC_LIBRARIES)
+        message(WARNING
+            "qt_internal_add_executable's PUBLIC_LIBRARIES option is deprecated, and will be "
+            "removed in a future Qt version. Use the LIBRARIES option instead.")
+    endif()
+
     qt_internal_extend_target("${name}"
         SOURCES ${arg_SOURCES}
         INCLUDE_DIRECTORIES ${private_includes}
         DEFINES ${arg_DEFINES}
-        LIBRARIES ${arg_LIBRARIES} Qt::PlatformCommonInternal
-        PUBLIC_LIBRARIES ${extra_libraries} ${arg_PUBLIC_LIBRARIES}
+        LIBRARIES
+            ${arg_LIBRARIES}
+            ${arg_PUBLIC_LIBRARIES}
+            Qt::PlatformCommonInternal
+            ${extra_libraries}
         DBUS_ADAPTOR_SOURCES "${arg_DBUS_ADAPTOR_SOURCES}"
         DBUS_ADAPTOR_FLAGS "${arg_DBUS_ADAPTOR_FLAGS}"
         DBUS_INTERFACE_SOURCES "${arg_DBUS_INTERFACE_SOURCES}"

cmake/QtTestHelpers.cmake

@@ -240,6 +240,12 @@ function(qt_internal_add_test name)
         set(version_arg VERSION "${arg_VERSION}")
     endif()
 
+    if(arg_PUBLIC_LIBRARIES)
+        message(WARNING
+            "qt_internal_add_test's PUBLIC_LIBRARIES option is deprecated, and will be "
+            "removed in a future Qt version. Use the LIBRARIES option instead.")
+    endif()
+
     # Handle cases where we have a qml test without source files
     if (arg_SOURCES)
         set(private_includes
@@ -260,8 +266,11 @@ function(qt_internal_add_test name)
                 ${private_includes}
             DEFINES
                 ${arg_DEFINES}
-            PUBLIC_LIBRARIES ${QT_CMAKE_EXPORT_NAMESPACE}::Core ${QT_CMAKE_EXPORT_NAMESPACE}::Test ${arg_PUBLIC_LIBRARIES}
-            LIBRARIES ${arg_LIBRARIES}
+            LIBRARIES
+                ${arg_LIBRARIES}
+                ${arg_PUBLIC_LIBRARIES}
+                ${QT_CMAKE_EXPORT_NAMESPACE}::Core
+                ${QT_CMAKE_EXPORT_NAMESPACE}::Test
             COMPILE_OPTIONS ${arg_COMPILE_OPTIONS}
             LINK_OPTIONS ${arg_LINK_OPTIONS}
             MOC_OPTIONS ${arg_MOC_OPTIONS}
@@ -284,7 +293,7 @@ function(qt_internal_add_test name)
 
         # QMLTest specifics
         qt_internal_extend_target("${name}" CONDITION arg_QMLTEST
-            PUBLIC_LIBRARIES ${QT_CMAKE_EXPORT_NAMESPACE}::QuickTest
+            LIBRARIES ${QT_CMAKE_EXPORT_NAMESPACE}::QuickTest
         )
 
         qt_internal_extend_target("${name}" CONDITION arg_QMLTEST AND NOT ANDROID
@@ -299,7 +308,7 @@ function(qt_internal_add_test name)
 
         # Android requires Qt::Gui so add it by default for tests
         qt_internal_extend_target("${name}" CONDITION ANDROID
-            PUBLIC_LIBRARIES ${QT_CMAKE_EXPORT_NAMESPACE}::Gui
+            LIBRARIES ${QT_CMAKE_EXPORT_NAMESPACE}::Gui
         )
     endif()
 

cmake/QtToolHelpers.cmake

@@ -43,6 +43,7 @@ function(qt_internal_add_tool target_name)
     set(multi_value_keywords
         EXTRA_CMAKE_FILES
         EXTRA_CMAKE_INCLUDES
+        PUBLIC_LIBRARIES
         ${__default_private_args})
     qt_parse_all_arguments(arg "qt_internal_add_tool" "${option_keywords}"
                                "${one_value_keywords}"
@@ -194,6 +195,12 @@ function(qt_internal_add_tool target_name)
 
     set(output_dir "${QT_BUILD_DIR}/${install_dir}")
 
+    if(arg_PUBLIC_LIBRARIES)
+        message(WARNING
+            "qt_internal_add_tool's PUBLIC_LIBRARIES option is deprecated, and will be "
+            "removed in a future Qt version. Use the LIBRARIES option instead.")
+    endif()
+
     qt_internal_add_executable("${target_name}"
         OUTPUT_DIRECTORY "${output_dir}"
         ${exceptions}
@@ -205,7 +212,10 @@ function(qt_internal_add_tool target_name)
             QT_USE_QSTRINGBUILDER
             ${arg_DEFINES}
         ${corelib}
-        LIBRARIES ${arg_LIBRARIES} Qt::PlatformToolInternal
+        LIBRARIES
+            ${arg_LIBRARIES}
+            ${arg_PUBLIC_LIBRARIES}
+            Qt::PlatformToolInternal
         COMPILE_OPTIONS ${arg_COMPILE_OPTIONS}
         LINK_OPTIONS ${arg_LINK_OPTIONS}
         MOC_OPTIONS ${arg_MOC_OPTIONS}