QTest: add removed_api.cpp and move deprecated functions to it

QtTest is not under the same Binary Compatibility guarantees as the
other modules, but let's try and do it where it's easy.

The toString() method can simply be removed from the header because it's
not a member function. Its deprecation wasn't marked with a version
number, so it starts now with 6.8.

Change-Id: Ie28eadac333c4bcd8c08fffd17c54faca7057b9c
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>

src/testlib/CMakeLists.txt

@@ -13,6 +13,7 @@ qt_internal_add_module(Test
     EXCEPTIONS
     SOURCES
         3rdparty/cycle_p.h
+        removed_api.cpp     # keep first
         qabstracttestlogger.cpp qabstracttestlogger_p.h
         qasciikey.cpp
         qbenchmark.cpp qbenchmark.h qbenchmark_p.h
@@ -70,6 +71,8 @@ qt_internal_add_module(Test
         QT_NO_MESSAGELOGCONTEXT
     LIBRARIES
         Qt::CorePrivate
+    NO_PCH_SOURCES
+        removed_api.cpp
     PUBLIC_LIBRARIES
         Qt::Core
     PRIVATE_MODULE_INTERFACE

src/testlib/qtestcase.cpp

@@ -3060,11 +3060,6 @@ char *QTest::toString(const char *str)
 /*! \internal
 */
 char *QTest::toString(const volatile void *p) // Use volatile to match compare_ptr_helper()
-{
-    return QTest::toString(const_cast<const void *>(p));
-}
-
-char *QTest::toString(const void *p)
 {
     char *msg = new char[128];
     qsnprintf(msg, 128, "%p", p);

src/testlib/qtestcase.h

@@ -402,7 +402,6 @@ namespace QTest
     Q_TESTLIB_EXPORT char *toPrettyUnicode(QStringView string);
     Q_TESTLIB_EXPORT char *toString(const char *);
     Q_TESTLIB_EXPORT char *toString(const volatile void *);
-    Q_TESTLIB_EXPORT char *toString(const void *); // ### FIXME: Qt 7: Remove
     Q_TESTLIB_EXPORT char *toString(const volatile QObject *);
 
     Q_TESTLIB_EXPORT void qInit(QObject *testObject, int argc = 0, char **argv = nullptr);
@@ -495,8 +494,6 @@ namespace QTest
     Q_TESTLIB_EXPORT Qt::Key asciiToKey(char ascii);
     Q_TESTLIB_EXPORT char keyToAscii(Qt::Key key);
 
-    // ### TODO: remove QTestResult::compare() overload that takes char * values
-    // when this overload is removed.
 #if QT_DEPRECATED_SINCE(6, 4)
     QT_DEPRECATED_VERSION_X_6_4("use an overload that takes function_ref as parameters, "
                                 "or an overload that takes only failure message, if you "

src/testlib/removed_api.cpp

@@ -0,0 +1,29 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+// Copyright (C) 2024 Intel Corporation.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#define QT_TESTLIB_BUILD_REMOVED_API
+
+#include "qtest.h"
+
+#if QT_TESTLIB_REMOVED_SINCE(6, 8)
+
+QT_BEGIN_NAMESPACE
+
+namespace QTest {
+
+Q_TESTLIB_EXPORT char *toString(const void *p)
+{
+    const volatile void *ptr = p;
+    return toString(ptr);
+}
+
+} // namespace QTest
+
+QT_END_NAMESPACE
+
+// #include "qotherheader.h"
+// implement removed functions from qotherheader.h
+// order sections alphabetically to reduce chances of merge conflicts
+
+#endif // QT_TESTLIB_REMOVED_SINCE(6, 8)