Merge "Merge remote-tracking branch 'origin/5.14' into 5.15"

24 files changed, 567 insertions, 257 deletions

diff --git a/src/3rdparty/VulkanMemoryAllocator/qt_attribution.json b/src/3rdparty/VulkanMemoryAllocator/qt_attribution.json
index 2548856ca7..0a5df738a8 100644
--- a/src/3rdparty/VulkanMemoryAllocator/qt_attribution.json
+++ b/src/3rdparty/VulkanMemoryAllocator/qt_attribution.json
@@ -2,7 +2,7 @@
     {
         "Id": "VulkanMemoryAllocator",
         "Name": "Vulkan Memory Allocator",
-        "QDocModule": "qtrhi",
+        "QDocModule": "qtgui",
         "Description": "Vulkan Memory Allocator",
         "QtUsage": "Memory management for the Vulkan backend of QRhi.",
 
diff --git a/src/corelib/doc/src/qtcore-index.qdoc b/src/corelib/doc/src/qtcore-index.qdoc
index 40a6584af0..29fc25f69d 100644
--- a/src/corelib/doc/src/qtcore-index.qdoc
+++ b/src/corelib/doc/src/qtcore-index.qdoc
@@ -56,7 +56,7 @@
     \include module-use.qdocinc using qt module
     \quotefile overview/using-qt-core.cmake
 
-    See also the \l[QtDoc]{Building with CMake} overview.
+    See also the \l[QtDoc]{Build with CMake} overview.
 
     \section2 Building with qmake
 
diff --git a/src/corelib/doc/src/resource-system.qdoc b/src/corelib/doc/src/resource-system.qdoc
index 69ec5e556b..f9ef317799 100644
--- a/src/corelib/doc/src/resource-system.qdoc
+++ b/src/corelib/doc/src/resource-system.qdoc
@@ -189,13 +189,13 @@
       XML file to indicate a file should be most compressed, regardless of
       which algorithms \c rcc supports.
 
-      \li \c{zstd}: use the \l{Zstandard}{https://zstd.net} library to compress
+      \li \c{zstd}: use the \l{https://zstd.net}{Zstandard} library to compress
       contents. Valid compression levels range from 1 to 19, 1 is least
       compression (least CPU time) and 19 is the most compression (most CPU
       time). The default level is 14. A special value of 0 tells the \c{zstd}
       library to choose an implementation-defined default.
 
-      \li \c{zlib}: use the \l{zlib}{https://zlib.net} library to compress
+      \li \c{zlib}: use the \l{https://zlib.net}{zlib} library to compress
       contents. Valid compression levels range from 1 to 9, with 1the least
       compression (least CPU time) and 9 the most compression (most CPU time).
       The special value 0 means "no compression" and should not be used. The
diff --git a/src/corelib/global/qendian.cpp b/src/corelib/global/qendian.cpp
index 7fd6e13d3b..98dc6a9a4b 100644
--- a/src/corelib/global/qendian.cpp
+++ b/src/corelib/global/qendian.cpp
@@ -137,7 +137,7 @@ QT_BEGIN_NAMESPACE
     \sa qToLittleEndian()
 */
 /*!
-    \fn template <typename T> T qFromLittleEndian(const void *src)
+    \fn template <typename T> inline T qFromLittleEndian(const void *src)
     \since 4.3
     \relates <QtEndian>
 
@@ -159,7 +159,7 @@ QT_BEGIN_NAMESPACE
     \sa qToLittleEndian()
 */
 /*!
-    \fn template <typename T> T qFromLittleEndian(T src)
+    \fn template <typename T> inline T qFromLittleEndian(T src)
     \since 4.3
     \relates <QtEndian>
     \overload
@@ -171,7 +171,7 @@ QT_BEGIN_NAMESPACE
     unmodified.
 */
 /*!
-    \fn template <typename T> T qFromLittleEndian(const void *src, qsizetype count, void *dest)
+    \fn template <typename T> inline T qFromLittleEndian(const void *src, qsizetype count, void *dest)
     \since 5.12
     \relates <QtEndian>
 
diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h
index 861f087c60..1bfe2c1615 100644
--- a/src/corelib/global/qglobal.h
+++ b/src/corelib/global/qglobal.h
@@ -944,6 +944,10 @@ QT_WARNING_POP
 #  define Q_DUMMY_COMPARISON_OPERATOR(C)
 #endif
 
+QT_WARNING_PUSH
+// warning: noexcept-expression evaluates to ‘false’ because of a call to ‘void swap(..., ...)'
+QT_WARNING_DISABLE_GCC("-Wnoexcept")
+
 namespace QtPrivate
 {
 namespace SwapExceptionTester { // insulate users from the "using std::swap" below
@@ -963,6 +967,8 @@ inline void qSwap(T &value1, T &value2)
     swap(value1, value2);
 }
 
+QT_WARNING_POP
+
 #if QT_DEPRECATED_SINCE(5, 0)
 Q_CORE_EXPORT QT_DEPRECATED void *qMalloc(size_t size) Q_ALLOC_SIZE(1);
 Q_CORE_EXPORT QT_DEPRECATED void qFree(void *ptr);
diff --git a/src/corelib/global/qlibraryinfo.cpp b/src/corelib/global/qlibraryinfo.cpp
index ecd26233cd..fa2098c757 100644
--- a/src/corelib/global/qlibraryinfo.cpp
+++ b/src/corelib/global/qlibraryinfo.cpp
@@ -562,9 +562,39 @@ static QString getRelocatablePrefix()
     HMODULE hModule = getWindowsModuleHandle();
     const int kBufferSize = 4096;
     wchar_t buffer[kBufferSize];
-    const int pathSize = GetModuleFileName(hModule, buffer, kBufferSize);
-    if (pathSize > 0)
-        prefixPath = prefixFromQtCoreLibraryHelper(QString::fromWCharArray(buffer, pathSize));
+    DWORD pathSize = GetModuleFileName(hModule, buffer, kBufferSize);
+    const QString qtCoreFilePath = QString::fromWCharArray(buffer, int(pathSize));
+    const QString qtCoreDirPath = QFileInfo(qtCoreFilePath).absolutePath();
+    pathSize = GetModuleFileName(NULL, buffer, kBufferSize);
+    const QString exeDirPath = QFileInfo(QString::fromWCharArray(buffer, int(pathSize))).absolutePath();
+    if (QFileInfo(exeDirPath) == QFileInfo(qtCoreDirPath)) {
+        // QtCore DLL is next to the executable. This is either a windeployqt'ed executable or an
+        // executable within the QT_HOST_BIN directory. We're detecting the latter case by checking
+        // whether there's an import library corresponding to our QtCore DLL in PREFIX/lib.
+        const QString libdir = QString::fromLatin1(
+            qt_configure_strs + qt_configure_str_offsets[QLibraryInfo::LibrariesPath - 1]);
+        const QLatin1Char slash('/');
+#if defined(Q_CC_MINGW)
+        const QString implibPrefix = QStringLiteral("lib");
+        const QString implibSuffix = QStringLiteral(".a");
+#else
+        const QString implibPrefix;
+        const QString implibSuffix = QStringLiteral(".lib");
+#endif
+        const QString qtCoreImpLibFileName = implibPrefix
+                + QFileInfo(qtCoreFilePath).completeBaseName() + implibSuffix;
+        const QString qtCoreImpLibPath = qtCoreDirPath
+                + slash + QLatin1String(QT_CONFIGURE_LIBLOCATION_TO_PREFIX_PATH)
+                + slash + libdir
+                + slash + qtCoreImpLibFileName;
+        if (!QFileInfo::exists(qtCoreImpLibPath)) {
+            // We did not find a corresponding import library and conclude that this is a
+            // windeployqt'ed executable.
+            return exeDirPath;
+        }
+    }
+    if (!qtCoreFilePath.isEmpty())
+        prefixPath = prefixFromQtCoreLibraryHelper(qtCoreFilePath);
 #else
 #error "The chosen platform / config does not support querying for a dynamic prefix."
 #endif
diff --git a/src/corelib/io/qresource.cpp b/src/corelib/io/qresource.cpp
index 3664a63050..bb608d8a72 100644
--- a/src/corelib/io/qresource.cpp
+++ b/src/corelib/io/qresource.cpp
@@ -280,9 +280,9 @@ static inline QStringList *resourceSearchPaths()
     RCC tool used to compress the payload.
 
     \value NoCompression    Contents are not compressed
-    \value ZlibCompression  Contents are compressed using \l{zlib}{https://zlib.net} and can
+    \value ZlibCompression  Contents are compressed using \l{https://zlib.net}{zlib} and can
                             be decompressed using the qUncompress() function.
-    \value ZstdCompression  Contents are compressed using \l{zstd}{https://zstd.net}. To
+    \value ZstdCompression  Contents are compressed using \l{https://zstd.net}{zstd}. To
                             decompress, use the \c{ZSTD_decompress} function from the zstd
                             library.
 
diff --git a/src/corelib/itemmodels/qitemselectionmodel.cpp b/src/corelib/itemmodels/qitemselectionmodel.cpp
index f4402c88dc..e4ac5da299 100644
--- a/src/corelib/itemmodels/qitemselectionmodel.cpp
+++ b/src/corelib/itemmodels/qitemselectionmodel.cpp
@@ -1627,10 +1627,9 @@ bool QItemSelectionModel::rowIntersectsSelection(int row, const QModelIndex &par
 
     QItemSelection sel = d->ranges;
     sel.merge(d->currentSelection, d->currentCommand);
-    for (int i = 0; i < sel.count(); ++i) {
-        QItemSelectionRange range = sel.at(i);
+    for (const QItemSelectionRange &range : qAsConst(sel)) {
         if (range.parent() != parent)
-          return false;
+            return false;
         int top = range.top();
         int bottom = range.bottom();
         int left = range.left();
@@ -1661,11 +1660,13 @@ bool QItemSelectionModel::columnIntersectsSelection(int column, const QModelInde
 
     QItemSelection sel = d->ranges;
     sel.merge(d->currentSelection, d->currentCommand);
-    for (int i = 0; i < sel.count(); ++i) {
-        int left = sel.at(i).left();
-        int right = sel.at(i).right();
-        int top =  sel.at(i).top();
-        int bottom =  sel.at(i).bottom();
+    for (const QItemSelectionRange &range : qAsConst(sel)) {
+        if (range.parent() != parent)
+            return false;
+        int top = range.top();
+        int bottom = range.bottom();
+        int left = range.left();
+        int right = range.right();
         if (left <= column && right >= column) {
             for (int j = top; j <= bottom; j++) {
                 const Qt::ItemFlags flags = d->model->index(j, column, parent).flags();
diff --git a/src/corelib/thread/qatomic.cpp b/src/corelib/thread/qatomic.cpp
index b1a7edad91..5c3ad9412f 100644
--- a/src/corelib/thread/qatomic.cpp
+++ b/src/corelib/thread/qatomic.cpp
@@ -234,22 +234,26 @@
     \sa QAtomicPointer
 */
 
-/*! \fn QAtomicInt::QAtomicInt(int value)
+/*!
+    \fn QAtomicInt::QAtomicInt(int value)
 
     Constructs a QAtomicInt with the given \a value.
 */
 
-/*! \fn QAtomicInteger<T>::QAtomicInteger(T value)
+/*!
+    \fn template <typename T> QAtomicInteger<T>::QAtomicInteger(T value)
 
     Constructs a QAtomicInteger with the given \a value.
 */
 
-/*! \fn template <typename T> QAtomicInteger<T>::QAtomicInteger(const QAtomicInteger &other)
+/*!
+    \fn template <typename T> QAtomicInteger<T>::QAtomicInteger(const QAtomicInteger &other)
 
     Constructs a copy of \a other.
 */
 
-/*! \fn template <typename T> QAtomicInteger &QAtomicInteger<T>::operator=(const QAtomicInteger &other)
+/*!
+    \fn template <typename T> QAtomicInteger &QAtomicInteger<T>::operator=(const QAtomicInteger &other)
 
     Assigns \a other to this QAtomicInteger and returns a reference to
     this QAtomicInteger.
@@ -344,19 +348,22 @@
     \sa storeRelaxed(), storeRelease()
 */
 
-/*! \fn template <typename T> bool QAtomicInteger<T>::isReferenceCountingNative()
+/*!
+    \fn template <typename T> bool QAtomicInteger<T>::isReferenceCountingNative()
 
     Returns \c true if reference counting is implemented using atomic
     processor instructions, false otherwise.
 */
 
-/*! \fn template <typename T> bool QAtomicInteger<T>::isReferenceCountingWaitFree()
+/*!
+    \fn template <typename T> bool QAtomicInteger<T>::isReferenceCountingWaitFree()
 
     Returns \c true if atomic reference counting is wait-free, false
     otherwise.
 */
 
-/*! \fn template <typename T> bool QAtomicInteger<T>::ref()
+/*!
+    \fn template <typename T> bool QAtomicInteger<T>::ref()
     Atomically increments the value of this QAtomicInteger. Returns \c true
     if the new value is non-zero, false otherwise.
 
@@ -394,7 +401,8 @@
     \sa ref(), operator++(), operator--(int)
 */
 
-/*! \fn template <typename T> bool QAtomicInteger<T>::deref()
+/*!
+    \fn template <typename T> bool QAtomicInteger<T>::deref()
     Atomically decrements the value of this QAtomicInteger. Returns \c true
     if the new value is non-zero, false otherwise.
 
@@ -432,18 +440,21 @@
     \sa deref(), operator--(), operator++(int)
 */
 
-/*! \fn template <typename T> bool QAtomicInteger<T>::isTestAndSetNative()
+/*!
+    \fn template <typename T> bool QAtomicInteger<T>::isTestAndSetNative()
 
     Returns \c true if test-and-set is implemented using atomic processor
     instructions, false otherwise.
 */
 
-/*! \fn template <typename T> bool QAtomicInteger<T>::isTestAndSetWaitFree()
+/*!
+    \fn template <typename T> bool QAtomicInteger<T>::isTestAndSetWaitFree()
 
     Returns \c true if atomic test-and-set is wait-free, false otherwise.
 */
 
-/*! \fn template <typename T> bool QAtomicInteger<T>::testAndSetRelaxed(T expectedValue, T newValue)
+/*!
+    \fn template <typename T> bool QAtomicInteger<T>::testAndSetRelaxed(T expectedValue, T newValue)
 
     Atomic test-and-set.
 
@@ -457,7 +468,8 @@
     processor to freely reorder memory accesses.
 */
 
-/*! \fn template <typename T> bool QAtomicInteger<T>::testAndSetAcquire(T expectedValue, T newValue)
+/*!
+    \fn template <typename T> bool QAtomicInteger<T>::testAndSetAcquire(T expectedValue, T newValue)
 
     Atomic test-and-set.
 
@@ -472,7 +484,8 @@
     be re-ordered before the atomic operation.
 */
 
-/*! \fn template <typename T> bool QAtomicInteger<T>::testAndSetRelease(T expectedValue, T newValue)
+/*!
+    \fn template <typename T> bool QAtomicInteger<T>::testAndSetRelease(T expectedValue, T newValue)
 
     Atomic test-and-set.
 
@@ -487,7 +500,8 @@
     re-ordered after the atomic operation.
 */
 
-/*! \fn template <typename T> bool QAtomicInteger<T>::testAndSetOrdered(T expectedValue, T newValue)
+/*!
+    \fn template <typename T> bool QAtomicInteger<T>::testAndSetOrdered(T expectedValue, T newValue)
 
     Atomic test-and-set.
 
@@ -502,19 +516,22 @@
     may not be re-ordered.
 */
 
-/*! \fn template <typename T> bool QAtomicInteger<T>::isFetchAndStoreNative()
+/*!
+    \fn template <typename T> bool QAtomicInteger<T>::isFetchAndStoreNative()
 
     Returns \c true if fetch-and-store is implemented using atomic
     processor instructions, false otherwise.
 */
 
-/*! \fn template <typename T> bool QAtomicInteger<T>::isFetchAndStoreWaitFree()
+/*!
+    \fn template <typename T> bool QAtomicInteger<T>::isFetchAndStoreWaitFree()
 
     Returns \c true if atomic fetch-and-store is wait-free, false
     otherwise.
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndStoreRelaxed(T newValue)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndStoreRelaxed(T newValue)
 
     Atomic fetch-and-store.
 
@@ -526,7 +543,8 @@
     processor to freely reorder memory accesses.
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndStoreAcquire(T newValue)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndStoreAcquire(T newValue)
 
     Atomic fetch-and-store.
 
@@ -539,7 +557,8 @@
     be re-ordered before the atomic operation.
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndStoreRelease(T newValue)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndStoreRelease(T newValue)
 
     Atomic fetch-and-store.
 
@@ -552,7 +571,8 @@
     re-ordered after the atomic operation.
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndStoreOrdered(T newValue)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndStoreOrdered(T newValue)
 
     Atomic fetch-and-store.
 
@@ -565,19 +585,22 @@
     may not be re-ordered.
 */
 
-/*! \fn template <typename T> bool QAtomicInteger<T>::isFetchAndAddNative()
+/*!
+    \fn template <typename T> bool QAtomicInteger<T>::isFetchAndAddNative()
 
     Returns \c true if fetch-and-add is implemented using atomic
     processor instructions, false otherwise.
 */
 
-/*! \fn template <typename T> bool QAtomicInteger<T>::isFetchAndAddWaitFree()
+/*!
+    \fn template <typename T> bool QAtomicInteger<T>::isFetchAndAddWaitFree()
 
     Returns \c true if atomic fetch-and-add is wait-free, false
     otherwise.
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndAddRelaxed(T valueToAdd)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndAddRelaxed(T valueToAdd)
 
     Atomic fetch-and-add.
 
@@ -591,7 +614,8 @@
     \sa operator+=(), fetchAndSubRelaxed()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndAddAcquire(T valueToAdd)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndAddAcquire(T valueToAdd)
 
     Atomic fetch-and-add.
 
@@ -606,7 +630,8 @@
     \sa operator+=(), fetchAndSubAcquire()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndAddRelease(T valueToAdd)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndAddRelease(T valueToAdd)
 
     Atomic fetch-and-add.
 
@@ -621,7 +646,8 @@
     \sa operator+=(), fetchAndSubRelease()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndAddOrdered(T valueToAdd)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndAddOrdered(T valueToAdd)
 
     Atomic fetch-and-add.
 
@@ -636,7 +662,8 @@
     \sa operator+=(), fetchAndSubOrdered()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::operator+=(T value)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::operator+=(T value)
     \since 5.3
 
     Atomic add-and-fetch.
@@ -650,7 +677,8 @@
     \sa fetchAndAddOrdered(), operator-=()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndSubRelaxed(T valueToSub)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndSubRelaxed(T valueToSub)
     \since 5.3
 
     Atomic fetch-and-sub.
@@ -665,7 +693,8 @@
     \sa operator-=(), fetchAndAddRelaxed()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndSubAcquire(T valueToSub)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndSubAcquire(T valueToSub)
     \since 5.3
 
     Atomic fetch-and-sub.
@@ -681,7 +710,8 @@
     \sa operator-=(), fetchAndAddAcquire()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndSubRelease(T valueToSub)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndSubRelease(T valueToSub)
     \since 5.3
 
     Atomic fetch-and-sub.
@@ -697,7 +727,8 @@
     \sa operator-=(), fetchAndAddRelease()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndSubOrdered(T valueToSub)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndSubOrdered(T valueToSub)
     \since 5.3
 
     Atomic fetch-and-sub.
@@ -713,7 +744,8 @@
     \sa operator-=(), fetchAndAddOrdered()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::operator-=(T value)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::operator-=(T value)
     \since 5.3
 
     Atomic sub-and-fetch.
@@ -727,7 +759,8 @@
     \sa fetchAndSubOrdered(), operator+=()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndOrRelaxed(T valueToOr)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndOrRelaxed(T valueToOr)
     \since 5.3
 
     Atomic fetch-and-or.
@@ -742,7 +775,8 @@
     \sa operator|=()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndOrAcquire(T valueToOr)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndOrAcquire(T valueToOr)
     \since 5.3
 
     Atomic fetch-and-or.
@@ -758,7 +792,8 @@
     \sa operator|=()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndOrRelease(T valueToOr)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndOrRelease(T valueToOr)
     \since 5.3
 
     Atomic fetch-and-or.
@@ -774,7 +809,8 @@
     \sa operator|=()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndOrOrdered(T valueToOr)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndOrOrdered(T valueToOr)
     \since 5.3
 
     Atomic fetch-and-or.
@@ -790,7 +826,8 @@
     \sa operator|=()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::operator|=(T value)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::operator|=(T value)
     \since 5.3
 
     Atomic or-and-fetch.
@@ -804,7 +841,8 @@
     \sa fetchAndOrOrdered()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndXorRelaxed(T valueToXor)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndXorRelaxed(T valueToXor)
     \since 5.3
 
     Atomic fetch-and-xor.
@@ -819,7 +857,8 @@
     \sa operator^=()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndXorAcquire(T valueToXor)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndXorAcquire(T valueToXor)
     \since 5.3
 
     Atomic fetch-and-xor.
@@ -835,7 +874,8 @@
     \sa operator^=()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndXorRelease(T valueToXor)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndXorRelease(T valueToXor)
     \since 5.3
 
     Atomic fetch-and-xor.
@@ -851,7 +891,8 @@
     \sa operator^=()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndXorOrdered(T valueToXor)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndXorOrdered(T valueToXor)
     \since 5.3
 
     Atomic fetch-and-xor.
@@ -867,7 +908,8 @@
     \sa operator^=()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::operator^=(T value)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::operator^=(T value)
     \since 5.3
 
     Atomic xor-and-fetch.
@@ -881,7 +923,8 @@
     \sa fetchAndXorOrdered()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndAndRelaxed(T valueToAnd)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndAndRelaxed(T valueToAnd)
     \since 5.3
 
     Atomic fetch-and-and.
@@ -896,7 +939,8 @@
     \sa operator&=()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndAndAcquire(T valueToAnd)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndAndAcquire(T valueToAnd)
     \since 5.3
 
     Atomic fetch-and-and.
@@ -912,7 +956,8 @@
     \sa operator&=()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndAndRelease(T valueToAnd)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndAndRelease(T valueToAnd)
     \since 5.3
 
     Atomic fetch-and-and.
@@ -928,7 +973,8 @@
     \sa operator&=()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::fetchAndAndOrdered(T valueToAnd)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::fetchAndAndOrdered(T valueToAnd)
     \since 5.3
 
     Atomic fetch-and-and.
@@ -944,7 +990,8 @@
     \sa operator&=()
 */
 
-/*! \fn template <typename T> T QAtomicInteger<T>::operator&=(T value)
+/*!
+    \fn template <typename T> T QAtomicInteger<T>::operator&=(T value)
     \since 5.3
 
     Atomic add-and-fetch.
@@ -1287,17 +1334,20 @@
     \sa QAtomicInteger
 */
 
-/*! \fn template <typename T> QAtomicPointer<T>::QAtomicPointer(T *value)
+/*!
+    \fn template <typename T> QAtomicPointer<T>::QAtomicPointer(T *value)
 
     Constructs a QAtomicPointer with the given \a value.
 */
 
-/*! \fn template <typename T> QAtomicPointer<T>::QAtomicPointer(const QAtomicPointer<T> &other)
+/*!
+    \fn template <typename T> QAtomicPointer<T>::QAtomicPointer(const QAtomicPointer<T> &other)
 
     Constructs a copy of \a other.
 */
 
-/*! \fn template <typename T> QAtomicPointer &QAtomicPointer<T>::operator=(const QAtomicPointer &other)
+/*!
+    \fn template <typename T> QAtomicPointer &QAtomicPointer<T>::operator=(const QAtomicPointer &other)
 
     Assigns \a other to this QAtomicPointer and returns a reference to
     this QAtomicPointer.
@@ -1369,18 +1419,21 @@
     \sa storeRelaxed(), loadRelaxed()
 */
 
-/*! \fn template <typename T> bool QAtomicPointer<T>::isTestAndSetNative()
+/*!
+    \fn template <typename T> bool QAtomicPointer<T>::isTestAndSetNative()
 
     Returns \c true if test-and-set is implemented using atomic processor
     instructions, false otherwise.
 */
 
-/*! \fn template <typename T> bool QAtomicPointer<T>::isTestAndSetWaitFree()
+/*!
+    \fn template <typename T> bool QAtomicPointer<T>::isTestAndSetWaitFree()
 
     Returns \c true if atomic test-and-set is wait-free, false otherwise.
 */
 
-/*! \fn template <typename T> bool QAtomicPointer<T>::testAndSetRelaxed(T *expectedValue, T *newValue)
+/*!
+    \fn template <typename T> bool QAtomicPointer<T>::testAndSetRelaxed(T *expectedValue, T *newValue)
 
     Atomic test-and-set.
 
@@ -1394,7 +1447,8 @@
     processor to freely reorder memory accesses.
 */
 
-/*! \fn template <typename T> bool QAtomicPointer<T>::testAndSetAcquire(T *expectedValue, T *newValue)
+/*!
+    \fn template <typename T> bool QAtomicPointer<T>::testAndSetAcquire(T *expectedValue, T *newValue)
 
     Atomic test-and-set.
 
@@ -1409,7 +1463,8 @@
     be re-ordered before the atomic operation.
 */
 
-/*! \fn template <typename T> bool QAtomicPointer<T>::testAndSetRelease(T *expectedValue, T *newValue)
+/*!
+    \fn template <typename T> bool QAtomicPointer<T>::testAndSetRelease(T *expectedValue, T *newValue)
 
     Atomic test-and-set.
 
@@ -1424,7 +1479,8 @@
     re-ordered after the atomic operation.
 */
 
-/*! \fn template <typename T> bool QAtomicPointer<T>::testAndSetOrdered(T *expectedValue, T *newValue)
+/*!
+    \fn template <typename T> bool QAtomicPointer<T>::testAndSetOrdered(T *expectedValue, T *newValue)
 
     Atomic test-and-set.
 
@@ -1439,19 +1495,22 @@
     may not be re-ordered.
 */
 
-/*! \fn template <typename T> bool QAtomicPointer<T>::isFetchAndStoreNative()
+/*!
+    \fn template <typename T> bool QAtomicPointer<T>::isFetchAndStoreNative()
 
     Returns \c true if fetch-and-store is implemented using atomic
     processor instructions, false otherwise.
 */
 
-/*! \fn template <typename T> bool QAtomicPointer<T>::isFetchAndStoreWaitFree()
+/*!
+    \fn template <typename T> bool QAtomicPointer<T>::isFetchAndStoreWaitFree()
 
     Returns \c true if atomic fetch-and-store is wait-free, false
     otherwise.
 */
 
-/*! \fn template <typename T> T *QAtomicPointer<T>::fetchAndStoreRelaxed(T *newValue)
+/*!
+    \fn template <typename T> T *QAtomicPointer<T>::fetchAndStoreRelaxed(T *newValue)
 
     Atomic fetch-and-store.
 
@@ -1463,7 +1522,8 @@
     processor to freely reorder memory accesses.
 */
 
-/*! \fn template <typename T> T *QAtomicPointer<T>::fetchAndStoreAcquire(T *newValue)
+/*!
+    \fn template <typename T> T *QAtomicPointer<T>::fetchAndStoreAcquire(T *newValue)
 
     Atomic fetch-and-store.
 
@@ -1476,7 +1536,8 @@
     be re-ordered before the atomic operation.
 */
 
-/*! \fn template <typename T> T *QAtomicPointer<T>::fetchAndStoreRelease(T *newValue)
+/*!
+    \fn template <typename T> T *QAtomicPointer<T>::fetchAndStoreRelease(T *newValue)
 
     Atomic fetch-and-store.
 
@@ -1489,7 +1550,8 @@
     re-ordered after the atomic operation.
 */
 
-/*! \fn template <typename T> T *QAtomicPointer<T>::fetchAndStoreOrdered(T *newValue)
+/*!
+    \fn template <typename T> T *QAtomicPointer<T>::fetchAndStoreOrdered(T *newValue)
 
     Atomic fetch-and-store.
 
@@ -1502,19 +1564,22 @@
     may not be re-ordered.
 */
 
-/*! \fn template <typename T> bool QAtomicPointer<T>::isFetchAndAddNative()
+/*!
+    \fn template <typename T> bool QAtomicPointer<T>::isFetchAndAddNative()
 
     Returns \c true if fetch-and-add is implemented using atomic
     processor instructions, false otherwise.
 */
 
-/*! \fn template <typename T> bool QAtomicPointer<T>::isFetchAndAddWaitFree()
+/*!
+    \fn template <typename T> bool QAtomicPointer<T>::isFetchAndAddWaitFree()
 
     Returns \c true if atomic fetch-and-add is wait-free, false
     otherwise.
 */
 
-/*! \fn template <typename T> T *QAtomicPointer<T>::fetchAndAddRelaxed(qptrdiff valueToAdd)
+/*!
+    \fn template <typename T> T *QAtomicPointer<T>::fetchAndAddRelaxed(qptrdiff valueToAdd)
 
     Atomic fetch-and-add.
 
@@ -1526,7 +1591,8 @@
     processor to freely reorder memory accesses.
 */
 
-/*! \fn template <typename T> T *QAtomicPointer<T>::fetchAndAddAcquire(qptrdiff valueToAdd)
+/*!
+    \fn template <typename T> T *QAtomicPointer<T>::fetchAndAddAcquire(qptrdiff valueToAdd)
 
     Atomic fetch-and-add.
 
@@ -1539,7 +1605,8 @@
     be re-ordered before the atomic operation.
 */
 
-/*! \fn template <typename T> T *QAtomicPointer<T>::fetchAndAddRelease(qptrdiff valueToAdd)
+/*!
+    \fn template <typename T> T *QAtomicPointer<T>::fetchAndAddRelease(qptrdiff valueToAdd)
 
     Atomic fetch-and-add.
 
@@ -1552,7 +1619,8 @@
     re-ordered after the atomic operation.
 */
 
-/*! \fn template <typename T> T *QAtomicPointer<T>::fetchAndAddOrdered(qptrdiff valueToAdd)
+/*!
+    \fn template <typename T> T *QAtomicPointer<T>::fetchAndAddOrdered(qptrdiff valueToAdd)
 
     Atomic fetch-and-add.
 
diff --git a/src/corelib/thread/qatomic.h b/src/corelib/thread/qatomic.h
index a3b9be0729..aa57ddc610 100644
--- a/src/corelib/thread/qatomic.h
+++ b/src/corelib/thread/qatomic.h
@@ -50,6 +50,10 @@ QT_BEGIN_NAMESPACE
 QT_WARNING_PUSH
 QT_WARNING_DISABLE_GCC("-Wextra")
 
+#ifdef Q_CLANG_QDOC
+#  undef QT_BASIC_ATOMIC_HAS_CONSTRUCTORS
+#endif
+
 // High-level atomic integer operations
 template <typename T>
 class QAtomicInteger : public QBasicAtomicInteger<T>
@@ -194,7 +198,9 @@ public:
 #ifdef Q_QDOC
     T *load() const;
     T *loadAcquire() const;
+    T *loadRelaxed() const;
     void store(T *newValue);
+    void storeRelaxed(T *newValue);
     void storeRelease(T *newValue);
 
     static Q_DECL_CONSTEXPR bool isTestAndSetNative();
diff --git a/src/corelib/time/qcalendar.cpp b/src/corelib/time/qcalendar.cpp
index d308aeba2b..6a4623ce92 100644
--- a/src/corelib/time/qcalendar.cpp
+++ b/src/corelib/time/qcalendar.cpp
@@ -100,7 +100,7 @@ struct Registry {
         if (id == QCalendar::System::User) {
             byId.push_back(calendar);
         } else {
-            Q_ASSERT(byId.at(size_t(id)) == nullptr);
+            Q_ASSERT(byId[size_t(id)] == nullptr);
             byId[size_t(id)] = calendar;
         }
         if (id == QCalendar::System::Gregorian) {
@@ -618,7 +618,7 @@ const QCalendarBackend *QCalendarBackend::fromEnum(QCalendar::System system)
     if (calendarRegistry.isDestroyed() || system == QCalendar::System::User)
         return nullptr;
     Q_ASSERT(calendarRegistry->byId.size() >= size_t(system));
-    if (auto *c = calendarRegistry->byId.at(size_t(system)))
+    if (auto *c = calendarRegistry->byId[size_t(system)])
         return c;
     switch (system) {
     case QCalendar::System::Gregorian:
diff --git a/src/gui/configure.json b/src/gui/configure.json
index 7f4d7cc6af..4de159d97a 100644
--- a/src/gui/configure.json
+++ b/src/gui/configure.json
@@ -373,6 +373,7 @@
             },
             "headers": "jpeglib.h",
             "sources": [
+                { "type": "pkgConfig", "args": "libjpeg" },
                 { "libs": "-llibjpeg", "condition": "config.msvc" },
                 "-ljpeg"
             ]
diff --git a/src/gui/doc/src/qtgui.qdoc b/src/gui/doc/src/qtgui.qdoc
index c4e7d32de1..392b6040cb 100644
--- a/src/gui/doc/src/qtgui.qdoc
+++ b/src/gui/doc/src/qtgui.qdoc
@@ -62,7 +62,7 @@
     \include module-use.qdocinc using qt module
     \quotefile overview/using-qt-gui.cmake
 
-    See also the \l[QtDoc]{Building with CMake} overview.
+    See also the \l[QtDoc]{Build with CMake} overview.
 
     \section2 Building with qmake
 
diff --git a/src/gui/kernel/qwindow.cpp b/src/gui/kernel/qwindow.cpp
index 74e0e6401e..c4c7de1b2e 100644
--- a/src/gui/kernel/qwindow.cpp
+++ b/src/gui/kernel/qwindow.cpp
@@ -1344,7 +1344,7 @@ Qt::WindowStates QWindow::windowStates() const
     This is a hint to the window manager that this window is a dialog or pop-up
     on behalf of the transient parent.
 
-    In order to cause the window to be centered above its transient parent by
+    In order to cause the window to be centered above its transient \a parent by
     default, depending on the window manager, it may also be necessary to call
     setFlags() with a suitable \l Qt::WindowType (such as \c Qt::Dialog).
 
diff --git a/src/gui/opengl/qopenglextrafunctions.h b/src/gui/opengl/qopenglextrafunctions.h
index a68e269065..faac2dce4e 100644
--- a/src/gui/opengl/qopenglextrafunctions.h
+++ b/src/gui/opengl/qopenglextrafunctions.h
@@ -54,7 +54,7 @@
 
 // GLES build without having included gl32.h -> GLDEBUGPROC is still need for the protos, define it here
 #if defined(QT_OPENGL_ES_2) && !defined(QT_OPENGL_ES_3_2)
-typedef void (QOPENGLF_APIENTRYP  *GLDEBUGPROC)(GLenum source,GLenum type,GLuint id,GLenum severity,GLsizei length,const GLchar *message,const void *userParam);
+typedef void (QOPENGLF_APIENTRY  *GLDEBUGPROC)(GLenum source,GLenum type,GLuint id,GLenum severity,GLsizei length,const GLchar *message,const void *userParam);
 #endif
 
 QT_BEGIN_NAMESPACE
diff --git a/src/network/ssl/qsslsocket.cpp b/src/network/ssl/qsslsocket.cpp
index 690251727d..0828a795f1 100644
--- a/src/network/ssl/qsslsocket.cpp
+++ b/src/network/ssl/qsslsocket.cpp
@@ -1543,7 +1543,7 @@ bool QSslSocket::addDefaultCaCertificates(const QString &path, QSsl::EncodingFor
     SSL socket's CA certificate database is initialized to the default
     CA certificate database.
 
-    \sa QSslConfiguration::caCertificates(), QSslConfiguration::addCaCertificates()
+    \sa QSslConfiguration::addCaCertificates()
 */
 void QSslSocket::addDefaultCaCertificate(const QSslCertificate &certificate)
 {
diff --git a/src/plugins/platforms/android/qandroidassetsfileenginehandler.cpp b/src/plugins/platforms/android/qandroidassetsfileenginehandler.cpp
index 26e72a480f..fcc08ea00d 100644
--- a/src/plugins/platforms/android/qandroidassetsfileenginehandler.cpp
+++ b/src/plugins/platforms/android/qandroidassetsfileenginehandler.cpp
@@ -72,9 +72,10 @@ static inline QString prefixedPath(QString path)
 struct AssetItem {
     enum class Type {
         File,
-        Folder
+        Folder,
+        Invalid
     };
-
+    AssetItem() = default;
     AssetItem (const QString &rawName)
         : name(rawName)
     {
@@ -92,21 +93,47 @@ using AssetItemList = QVector<AssetItem>;
 class FolderIterator : public AssetItemList
 {
 public:
-    static QSharedPointer<FolderIterator> fromCache(const QString &path)
+    static QSharedPointer<FolderIterator> fromCache(const QString &path, bool clone)
     {
         QMutexLocker lock(&m_assetsCacheMutex);
         QSharedPointer<FolderIterator> *folder = m_assetsCache.object(path);
         if (!folder) {
             folder = new QSharedPointer<FolderIterator>{new FolderIterator{path}};
-            if (!m_assetsCache.insert(path, folder)) {
+            if ((*folder)->empty() || !m_assetsCache.insert(path, folder)) {
                 QSharedPointer<FolderIterator> res = *folder;
                 delete folder;
                 return res;
             }
         }
-        return *folder;
+        return clone ? QSharedPointer<FolderIterator>{new FolderIterator{*(*folder)}} : *folder;
+    }
+
+    static AssetItem::Type fileType(const QString &filePath)
+    {
+        const QStringList paths = filePath.split(QLatin1Char('/'));
+        QString fullPath;
+        AssetItem::Type res = AssetItem::Type::Invalid;
+        for (const auto &path: paths) {
+            auto folder = fromCache(fullPath, false);
+            auto it = std::lower_bound(folder->begin(), folder->end(), AssetItem{path}, [](const AssetItem &val, const AssetItem &assetItem) {
+                return val.name < assetItem.name;
+            });
+            if (it == folder->end() || it->name != path)
+                return AssetItem::Type::Invalid;
+            if (!fullPath.isEmpty())
+                fullPath.append(QLatin1Char('/'));
+            fullPath += path;
+            res = it->type;
+        }
+        return res;
     }
 
+    FolderIterator(const FolderIterator &other)
+        : AssetItemList(other)
+        , m_index(-1)
+        , m_path(other.m_path)
+    {}
+
     FolderIterator(const QString &path)
         : m_path(path)
     {
@@ -118,8 +145,12 @@ public:
             QJNIEnvironmentPrivate env;
             jobjectArray jFiles = static_cast<jobjectArray>(files.object());
             const jint nFiles = env->GetArrayLength(jFiles);
-            for (int i = 0; i < nFiles; ++i)
-                push_back({QJNIObjectPrivate(env->GetObjectArrayElement(jFiles, i)).toString()});
+            for (int i = 0; i < nFiles; ++i) {
+                AssetItem item{QJNIObjectPrivate(env->GetObjectArrayElement(jFiles, i)).toString()};
+                insert(std::upper_bound(begin(), end(), item, [](const auto &a, const auto &b){
+                    return a.name < b.name;
+                }), item);
+            }
         }
         m_path = assetsPrefix + QLatin1Char('/') + m_path + QLatin1Char('/');
         m_path.replace(QLatin1String("//"), QLatin1String("/"));
@@ -169,7 +200,7 @@ public:
                                       const QString &path)
         : QAbstractFileEngineIterator(filters, nameFilters)
     {
-        m_stack.push_back(FolderIterator::fromCache(cleanedAssetPath(path)));
+        m_stack.push_back(FolderIterator::fromCache(cleanedAssetPath(path), true));
         if (m_stack.last()->empty())
             m_stack.pop_back();
     }
@@ -215,7 +246,7 @@ public:
         if (!res)
             return {};
         if (res->second.type == AssetItem::Type::Folder) {
-            m_stack.push_back(FolderIterator::fromCache(cleanedAssetPath(currentFilePath())));
+            m_stack.push_back(FolderIterator::fromCache(cleanedAssetPath(currentFilePath()), true));
             if (m_stack.last()->empty())
                 m_stack.pop_back();
         }
@@ -257,6 +288,7 @@ public:
             m_assetFile = 0;
             return true;
         }
+        m_isFolder = false;
         return false;
     }
 
@@ -305,12 +337,12 @@ public:
 
     FileFlags fileFlags(FileFlags type = FileInfoAll) const override
     {
-        FileFlags flags(ReadOwnerPerm|ReadUserPerm|ReadGroupPerm|ReadOtherPerm|ExistsFlag);
+        FileFlags commonFlags(ReadOwnerPerm|ReadUserPerm|ReadGroupPerm|ReadOtherPerm|ExistsFlag);
+        FileFlags flags;
         if (m_assetFile)
-            flags |= FileType;
+            flags = FileType | commonFlags;
         else if (m_isFolder)
-            flags |= DirectoryType;
-
+            flags = DirectoryType | commonFlags;
         return type & flags;
     }
 
@@ -341,9 +373,20 @@ public:
 
     void setFileName(const QString &file) override
     {
+        if (m_fileName == cleanedAssetPath(file))
+            return;
         close();
         m_fileName = cleanedAssetPath(file);
-        m_isFolder = !open(QIODevice::ReadOnly) && !FolderIterator::fromCache(m_fileName)->empty();
+        switch (FolderIterator::fileType(m_fileName)) {
+        case AssetItem::Type::File:
+            open(QIODevice::ReadOnly);
+            break;
+        case AssetItem::Type::Folder:
+            m_isFolder = true;
+            break;
+        case AssetItem::Type::Invalid:
+            break;
+        }
     }
 
     Iterator *beginEntryList(QDir::Filters filters, const QStringList &filterNames) override
@@ -355,9 +398,9 @@ public:
 
 private:
     AAsset *m_assetFile = nullptr;
-    AAssetManager *m_assetManager;
+    AAssetManager *m_assetManager = nullptr;
     QString m_fileName;
-    bool m_isFolder;
+    bool m_isFolder = false;
 };
 
 
diff --git a/src/plugins/platforms/cocoa/qcocoascreen.h b/src/plugins/platforms/cocoa/qcocoascreen.h
index 7ec9a2b5af..dcf6f1c753 100644
--- a/src/plugins/platforms/cocoa/qcocoascreen.h
+++ b/src/plugins/platforms/cocoa/qcocoascreen.h
@@ -53,9 +53,6 @@ class QCocoaIntegration;
 class QCocoaScreen : public QPlatformScreen
 {
 public:
-    static void initializeScreens();
-    static void cleanupScreens();
-
     ~QCocoaScreen();
 
     // ----------------------------------------------------
@@ -79,7 +76,6 @@ public:
     // ----------------------------------------------------
 
     NSScreen *nativeScreen() const;
-    void updateProperties();
 
     void requestUpdate();
     void deliverUpdateRequests();
@@ -88,6 +84,7 @@ public:
     static QCocoaScreen *primaryScreen();
     static QCocoaScreen *get(NSScreen *nsScreen);
     static QCocoaScreen *get(CGDirectDisplayID displayId);
+    static QCocoaScreen *get(CFUUIDRef uuid);
 
     static CGPoint mapToNative(const QPointF &pos, QCocoaScreen *screen = QCocoaScreen::primaryScreen());
     static CGRect mapToNative(const QRectF &rect, QCocoaScreen *screen = QCocoaScreen::primaryScreen());
@@ -95,11 +92,23 @@ public:
     static QRectF mapFromNative(CGRect rect, QCocoaScreen *screen = QCocoaScreen::primaryScreen());
 
 private:
-    QCocoaScreen(CGDirectDisplayID displayId);
+    static void initializeScreens();
+    static void updateScreens();
+    static void cleanupScreens();
+
+    static bool updateScreensIfNeeded();
+    static NSArray *s_screenConfigurationBeforeUpdate;
+
     static void add(CGDirectDisplayID displayId);
+    QCocoaScreen(CGDirectDisplayID displayId);
+    void update(CGDirectDisplayID displayId);
     void remove();
 
+    bool isOnline() const;
+    bool isMirroring() const;
+
     CGDirectDisplayID m_displayId = kCGNullDirectDisplay;
+    CGDirectDisplayID displayId() const { return m_displayId; }
 
     QRect m_geometry;
     QRect m_availableGeometry;
@@ -116,6 +125,8 @@ private:
     dispatch_source_t m_displayLinkSource = nullptr;
     QAtomicInt m_pendingUpdates;
 
+    friend class QCocoaIntegration;
+    friend class QCocoaWindow;
     friend QDebug operator<<(QDebug debug, const QCocoaScreen *screen);
 };
 
diff --git a/src/plugins/platforms/cocoa/qcocoascreen.mm b/src/plugins/platforms/cocoa/qcocoascreen.mm
index bd5c95b9d0..e4dd4cf6c6 100644
--- a/src/plugins/platforms/cocoa/qcocoascreen.mm
+++ b/src/plugins/platforms/cocoa/qcocoascreen.mm
@@ -57,6 +57,7 @@ QT_BEGIN_NAMESPACE
 namespace CoreGraphics {
     Q_NAMESPACE
     enum DisplayChange {
+        ReconfiguredWithFlagsMissing = 0,
         Moved = kCGDisplayMovedFlag,
         SetMain = kCGDisplaySetMainFlag,
         SetMode = kCGDisplaySetModeFlag,
@@ -71,73 +72,165 @@ namespace CoreGraphics {
     Q_ENUM_NS(DisplayChange)
 }
 
+NSArray *QCocoaScreen::s_screenConfigurationBeforeUpdate = nil;
+
 void QCocoaScreen::initializeScreens()
 {
-    uint32_t displayCount = 0;
-    if (CGGetActiveDisplayList(0, nullptr, &displayCount) != kCGErrorSuccess)
-        qFatal("Failed to get number of active displays");
-
-    CGDirectDisplayID activeDisplays[displayCount];
-    if (CGGetActiveDisplayList(displayCount, &activeDisplays[0], &displayCount) != kCGErrorSuccess)
-        qFatal("Failed to get active displays");
-
-    for (CGDirectDisplayID displayId : activeDisplays)
-        QCocoaScreen::add(displayId);
+    updateScreens();
 
     CGDisplayRegisterReconfigurationCallback([](CGDirectDisplayID displayId, CGDisplayChangeSummaryFlags flags, void *userInfo) {
-        if (flags & kCGDisplayBeginConfigurationFlag)
-            return; // Wait for changes to apply
-
         Q_UNUSED(userInfo);
 
-        qCDebug(lcQpaScreen).verbosity(0).nospace() << "Display reconfiguration"
-            << " (" << QFlags<CoreGraphics::DisplayChange>(flags) << ")"
-            << " for displayId=" << displayId;
-
-        QCocoaScreen *cocoaScreen = QCocoaScreen::get(displayId);
+        // Displays are reconfigured in batches, and we want to update our screens
+        // once a batch ends, so that all the states of the displays are up to date.
+        static int displayReconfigurationsInProgress = 0;
+
+        const bool beforeReconfigure = flags & kCGDisplayBeginConfigurationFlag;
+        qCDebug(lcQpaScreen).verbosity(0).nospace() << "Display " << displayId
+                << (beforeReconfigure ? " about to reconfigure" : " was ")
+                << QFlags<CoreGraphics::DisplayChange>(flags)
+                << " with " << displayReconfigurationsInProgress
+                << " display configuration(s) in progress";
+
+        if (!flags) {
+            // CGDisplayRegisterReconfigurationCallback has been observed to be called
+            // with flags unset. This seems like a bug. The callback is not paired with
+            // a matching "completion" callback either, so we don't know whether to treat
+            // it as a begin or end of reconfigure.
+            return;
+        }
 
-        if ((flags & kCGDisplayAddFlag) || !cocoaScreen) {
-            if (!CGDisplayIsActive(displayId)) {
-                qCDebug(lcQpaScreen) << "Not adding inactive display" << displayId;
-                return; // Will be added when activated
+        if (beforeReconfigure) {
+            if (!displayReconfigurationsInProgress++) {
+                // There might have been a screen reconfigure before this that
+                // we didn't process yet, so do that now if that's the case.
+                updateScreensIfNeeded();
+
+                Q_ASSERT(!s_screenConfigurationBeforeUpdate);
+                s_screenConfigurationBeforeUpdate = NSScreen.screens;
+                qCDebug(lcQpaScreen, "Display reconfigure transaction started"
+                    " with screen configuration %p", s_screenConfigurationBeforeUpdate);
+
+                static void (^tryScreenUpdate)();
+                tryScreenUpdate = ^void () {
+                    qCDebug(lcQpaScreen) << "Attempting screen update from runloop block";
+                    if (!updateScreensIfNeeded())
+                        CFRunLoopPerformBlock(CFRunLoopGetMain(), kCFRunLoopCommonModes, tryScreenUpdate);
+                };
+                CFRunLoopPerformBlock(CFRunLoopGetMain(), kCFRunLoopCommonModes, tryScreenUpdate);
             }
-            QCocoaScreen::add(displayId);
-        } else if ((flags & kCGDisplayRemoveFlag) || !CGDisplayIsActive(displayId)) {
-            cocoaScreen->remove();
         } else {
-            // Detect changes to the primary screen immediately, instead of
-            // waiting for a display reconfigure with kCGDisplaySetMainFlag.
-            // This ensures that any property updates to the other screens
-            // will be in reference to the correct primary screen.
-            QCocoaScreen *mainDisplay = QCocoaScreen::get(CGMainDisplayID());
-            if (QGuiApplication::primaryScreen()->handle() != mainDisplay) {
-                mainDisplay->updateProperties();
-                qCInfo(lcQpaScreen) << "Primary screen changed to" << mainDisplay;
-                QWindowSystemInterface::handlePrimaryScreenChanged(mainDisplay);
-                if (cocoaScreen == mainDisplay)
-                    return; // Already reconfigured
-            }
+            Q_ASSERT_X(displayReconfigurationsInProgress, "QCococaScreen",
+                "Display configuration transactions are expected to be balanced");
 
-            cocoaScreen->updateProperties();
-            qCInfo(lcQpaScreen).nospace() << "Reconfigured " <<
-                (primaryScreen() == cocoaScreen ? "primary " : "")
-                << cocoaScreen;
+            if (!--displayReconfigurationsInProgress) {
+                qCDebug(lcQpaScreen) << "Display reconfigure transaction completed";
+                // We optimistically update now, in case the NSScreens have changed
+                updateScreensIfNeeded();
+            }
         }
     }, nullptr);
+
+    static QMacNotificationObserver screenParameterObserver(NSApplication.sharedApplication,
+        NSApplicationDidChangeScreenParametersNotification, [&]() {
+            qCDebug(lcQpaScreen) << "Received screen parameter change notification";
+            updateScreensIfNeeded(); // As a last resort we update screens here
+        });
+}
+
+bool QCocoaScreen::updateScreensIfNeeded()
+{
+    if (!s_screenConfigurationBeforeUpdate) {
+        qCDebug(lcQpaScreen) << "QScreens have already been updated, all good";
+        return true;
+    }
+
+    if (s_screenConfigurationBeforeUpdate == NSScreen.screens) {
+        qCDebug(lcQpaScreen) << "Still waiting for NSScreen configuration change";
+        return false;
+    }
+
+    qCDebug(lcQpaScreen, "NSScreen configuration changed to %p", NSScreen.screens);
+    updateScreens();
+
+    s_screenConfigurationBeforeUpdate = nil;
+    return true;
+}
+
+/*
+    Update the list of available QScreens, and the properties of existing screens.
+
+    At this point we rely on the NSScreen.screens to be up to date.
+*/
+void QCocoaScreen::updateScreens()
+{
+    uint32_t displayCount = 0;
+    if (CGGetOnlineDisplayList(0, nullptr, &displayCount) != kCGErrorSuccess)
+        qFatal("Failed to get number of online displays");
+
+    QVector<CGDirectDisplayID> onlineDisplays(displayCount);
+    if (CGGetOnlineDisplayList(displayCount, onlineDisplays.data(), &displayCount) != kCGErrorSuccess)
+        qFatal("Failed to get online displays");
+
+    qCInfo(lcQpaScreen) << "Updating screens with" << displayCount
+        << "online displays:" << onlineDisplays;
+
+    // TODO: Verify whether we can always assume the main display is first
+    int mainDisplayIndex = onlineDisplays.indexOf(CGMainDisplayID());
+    if (mainDisplayIndex < 0) {
+        qCWarning(lcQpaScreen) << "Main display not in list of online displays!";
+    } else if (mainDisplayIndex > 0) {
+        qCWarning(lcQpaScreen) << "Main display not first display, making sure it is";
+        onlineDisplays.move(mainDisplayIndex, 0);
+    }
+
+    for (CGDirectDisplayID displayId : onlineDisplays) {
+        Q_ASSERT(CGDisplayIsOnline(displayId));
+
+        if (CGDisplayMirrorsDisplay(displayId))
+            continue;
+
+        // A single physical screen can map to multiple displays IDs,
+        // depending on which GPU is in use or which physical port the
+        // screen is connected to. By mapping the display ID to a UUID,
+        // which are shared between displays that target the same screen,
+        // we can pick an existing QScreen to update instead of needlessly
+        // adding and removing QScreens.
+        QCFType<CFUUIDRef> uuid = CGDisplayCreateUUIDFromDisplayID(displayId);
+        Q_ASSERT(uuid);
+
+        if (QCocoaScreen *existingScreen = QCocoaScreen::get(uuid)) {
+            existingScreen->update(displayId);
+            qCInfo(lcQpaScreen) << "Updated" << existingScreen;
+            if (CGDisplayIsMain(displayId) && existingScreen != qGuiApp->primaryScreen()->handle()) {
+                qCInfo(lcQpaScreen) << "Primary screen changed to" << existingScreen;
+                QWindowSystemInterface::handlePrimaryScreenChanged(existingScreen);
+            }
+        } else {
+            QCocoaScreen::add(displayId);
+        }
+    }
+
+    for (QScreen *screen : QGuiApplication::screens()) {
+        QCocoaScreen *platformScreen = static_cast<QCocoaScreen*>(screen->handle());
+        if (!platformScreen->isOnline() || platformScreen->isMirroring())
+            platformScreen->remove();
+    }
 }
 
 void QCocoaScreen::add(CGDirectDisplayID displayId)
 {
     const bool isPrimary = CGDisplayIsMain(displayId);
     QCocoaScreen *cocoaScreen = new QCocoaScreen(displayId);
-    qCInfo(lcQpaScreen).nospace() << "Adding " << (isPrimary ? "new primary " : "") << cocoaScreen;
+    qCInfo(lcQpaScreen) << "Adding" << cocoaScreen
+        << (isPrimary ? "as new primary screen" : "");
     QWindowSystemInterface::handleScreenAdded(cocoaScreen, isPrimary);
 }
 
 QCocoaScreen::QCocoaScreen(CGDirectDisplayID displayId)
     : QPlatformScreen(), m_displayId(displayId)
 {
-    updateProperties();
+    update(m_displayId);
     m_cursor = new QCocoaCursor;
 }
 
@@ -150,8 +243,6 @@ void QCocoaScreen::cleanupScreens()
 
 void QCocoaScreen::remove()
 {
-    m_displayId = kCGNullDirectDisplay; // Prevent stale references during removal
-
     // This may result in the application responding to QGuiApplication::screenRemoved
     // by moving the window to another screen, either by setGeometry, or by setScreen.
     // If the window isn't moved by the application, Qt will as a fallback move it to
@@ -163,7 +254,7 @@ void QCocoaScreen::remove()
     // QCocoaWindow::windowDidChangeScreen. At that point the window will appear to have
     // already changed its screen, but that's only true if comparing the Qt screens,
     // not when comparing the NSScreens.
-    qCInfo(lcQpaScreen).nospace() << "Removing " << (primaryScreen() == this ? "current primary " : "") << this;
+    qCInfo(lcQpaScreen) << "Removing " << this;
     QWindowSystemInterface::handleScreenRemoved(this);
 }
 
@@ -210,9 +301,14 @@ static QString displayName(CGDirectDisplayID displayID)
     return QString();
 }
 
-void QCocoaScreen::updateProperties()
+void QCocoaScreen::update(CGDirectDisplayID displayId)
 {
-    Q_ASSERT(m_displayId);
+    if (displayId != m_displayId) {
+        qCDebug(lcQpaScreen) << "Reconnecting" << this << "as display" << displayId;
+        m_displayId = displayId;
+    }
+
+    Q_ASSERT(isOnline());
 
     const QRect previousGeometry = m_geometry;
     const QRect previousAvailableGeometry = m_availableGeometry;
@@ -350,8 +446,8 @@ struct DeferredDebugHelper
 
 void QCocoaScreen::deliverUpdateRequests()
 {
-    if (!m_displayId)
-        return; // Screen removed
+    if (!isOnline())
+        return;
 
     QMacAutoReleasePool pool;
 
@@ -562,6 +658,29 @@ QPixmap QCocoaScreen::grabWindow(WId view, int x, int y, int width, int height)
     return windowPixmap;
 }
 
+bool QCocoaScreen::isOnline() const
+{
+    // When a display is disconnected CGDisplayIsOnline and other CGDisplay
+    // functions that take a displayId will not return false, but will start
+    // returning -1 to signal that the displayId is invalid. Some functions
+    // will also assert or even crash in this case, so it's important that
+    // we double check if a display is online before calling other functions.
+    auto isOnline = CGDisplayIsOnline(m_displayId);
+    static const uint32_t kCGDisplayIsDisconnected = int32_t(-1);
+    return isOnline != kCGDisplayIsDisconnected && isOnline;
+}
+
+/*
+    Returns true if a screen is mirroring another screen
+*/
+bool QCocoaScreen::isMirroring() const
+{
+    if (!isOnline())
+        return false;
+
+    return CGDisplayMirrorsDisplay(m_displayId);
+}
+
 /*!
     The screen used as a reference for global window geometry
 */
@@ -586,6 +705,12 @@ QList<QPlatformScreen*> QCocoaScreen::virtualSiblings() const
 
 QCocoaScreen *QCocoaScreen::get(NSScreen *nsScreen)
 {
+    if (s_screenConfigurationBeforeUpdate) {
+        qCWarning(lcQpaScreen) << "Trying to resolve screen while waiting for screen reconfigure!";
+        if (!updateScreensIfNeeded())
+            qCWarning(lcQpaScreen) << "Failed to do last minute screen update. Expect crashes.";
+    }
+
     return get(nsScreen.qt_displayId);
 }
 
@@ -600,23 +725,34 @@ QCocoaScreen *QCocoaScreen::get(CGDirectDisplayID displayId)
     return nullptr;
 }
 
+QCocoaScreen *QCocoaScreen::get(CFUUIDRef uuid)
+{
+    for (QScreen *screen : QGuiApplication::screens()) {
+        auto *platformScreen = static_cast<QCocoaScreen*>(screen->handle());
+        if (!platformScreen->isOnline())
+            continue;
+
+        auto displayId = platformScreen->displayId();
+        QCFType<CFUUIDRef> candidateUuid(CGDisplayCreateUUIDFromDisplayID(displayId));
+        Q_ASSERT(candidateUuid);
+
+        if (candidateUuid == uuid)
+            return platformScreen;
+    }
+
+    return nullptr;
+}
+
 NSScreen *QCocoaScreen::nativeScreen() const
 {
     if (!m_displayId)
         return nil; // The display has been disconnected
 
-    // A single display may have different displayIds depending on
-    // which GPU is in use or which physical port the display is
-    // connected to. By comparing UUIDs instead of display IDs we
-    // ensure that we always pick up the appropriate NSScreen.
-    QCFType<CFUUIDRef> uuid = CGDisplayCreateUUIDFromDisplayID(m_displayId);
-
-    for (NSScreen *screen in [NSScreen screens]) {
-        if (QCFType<CFUUIDRef>(CGDisplayCreateUUIDFromDisplayID(screen.qt_displayId)) == uuid)
+    for (NSScreen *screen in NSScreen.screens) {
+        if (screen.qt_displayId == m_displayId)
             return screen;
     }
 
-    qCWarning(lcQpaScreen) << "Could not find NSScreen for display ID" << m_displayId;
     return nil;
 }
 
@@ -651,11 +787,21 @@ QDebug operator<<(QDebug debug, const QCocoaScreen *screen)
     debug.nospace();
     debug << "QCocoaScreen(" << (const void *)screen;
     if (screen) {
-        debug << ", geometry=" << screen->geometry();
+        debug << ", " << screen->name();
+        if (screen->isOnline()) {
+            if (CGDisplayIsAsleep(screen->displayId()))
+                debug << ", Sleeping";
+            if (auto mirroring = CGDisplayMirrorsDisplay(screen->displayId()))
+                debug << ", mirroring=" << mirroring;
+        } else {
+            debug << ", Offline";
+        }
+        debug << ", " << screen->geometry();
         debug << ", dpr=" << screen->devicePixelRatio();
-        debug << ", name=" << screen->name();
-        debug << ", displayId=" << screen->m_displayId;
-        debug << ", native=" << screen->nativeScreen();
+        debug << ", displayId=" << screen->displayId();
+
+        if (auto nativeScreen = screen->nativeScreen())
+            debug << ", " << nativeScreen;
     }
     debug << ')';
     return debug;
diff --git a/src/sql/doc/src/sql-driver.qdoc b/src/sql/doc/src/sql-driver.qdoc
index 9c26c4089c..3a0fcfa1e7 100644
--- a/src/sql/doc/src/sql-driver.qdoc
+++ b/src/sql/doc/src/sql-driver.qdoc
@@ -171,7 +171,8 @@
     \section3 How to Build the QMYSQL Plugin on Windows
 
     You need to get the MySQL installation files (e.g.
-    \e{mysql-installer-web-community-8.0.18.0.msi}). Run the installer,
+    \l {https://dev.mysql.com/downloads/installer/}{mysql-installer-web-community-8.0.18.0.msi}).
+    Run the installer,
     select custom installation and install the MySQL C Connector
     which matches your Qt installation (x86 or x64).
     After installation make sure that the needed files are there:
@@ -192,9 +193,9 @@
 
     When you distribute your application, remember to include libmysql.dll
     in your installation package. It must be placed in the same folder
-    as the application executable. libmysql.dll additionally needs the
+    as the application executable. \e libmysql.dll additionally needs the
     MSVC runtime libraries which can be installed with vcredist.exe
-    (\l {https://support.microsoft.com/en-us/help/2977003/the-latest-supported-visual-c-downloads}(vcredist.exe)
+    (\l {https://support.microsoft.com/en-us/help/2977003/the-latest-supported-visual-c-downloads}{vcredist.exe}
 
     \target QOCI
     \section2 QOCI for the Oracle Call Interface (OCI)
@@ -356,10 +357,6 @@
     Windows NT based systems, this is the default. Note that the ODBC
     driver and the DBMS must also support Unicode.
 
-    Some driver managers and drivers do not support UNICODE. To use the
-    QODBC plugin with such drivers, it has to be compiled with
-    Q_ODBC_VERSION_2 defined.
-
     For the Oracle 9 ODBC driver (Windows), it is necessary to check
     "SQL_WCHAR support" in the ODBC driver manager otherwise Oracle
     will convert all Unicode strings to local 8-bit.
diff --git a/src/testlib/doc/src/qttest-best-practices.qdoc b/src/testlib/doc/src/qttest-best-practices.qdoc
index c7fee93c80..8ad67acce6 100644
--- a/src/testlib/doc/src/qttest-best-practices.qdoc
+++ b/src/testlib/doc/src/qttest-best-practices.qdoc
@@ -278,8 +278,8 @@
     \section2 Avoid Fixed Timeouts
 
     Avoid using hard-coded timeouts, such as QTest::qWait() to wait for some
-    conditions to become true. Consider using the \l QtSignalSpy class,
-    the \l QTRY_VERIFY() or \l QTRY_COMPARE() macros, or the \c QtSignalSpy
+    conditions to become true. Consider using the \l QSignalSpy class,
+    the \l QTRY_VERIFY() or \l QTRY_COMPARE() macros, or the \c QSignalSpy
     class in conjunction with the \c QTRY_ macro variants.
 
     The \c qWait() function can be used to set a delay for a fixed period
diff --git a/src/widgets/kernel/qapplication.cpp b/src/widgets/kernel/qapplication.cpp
index 57771b3e12..3577414713 100644
--- a/src/widgets/kernel/qapplication.cpp
+++ b/src/widgets/kernel/qapplication.cpp
@@ -142,16 +142,19 @@ QApplicationPrivate *QApplicationPrivate::self = nullptr;
 
 static void initSystemPalette()
 {
-    if (!QApplicationPrivate::sys_pal) {
-        QPalette defaultPlatte;
-        if (QApplicationPrivate::app_style)
-            defaultPlatte = QApplicationPrivate::app_style->standardPalette();
-        if (const QPalette *themePalette = QGuiApplicationPrivate::platformTheme()->palette()) {
-            QApplicationPrivate::setSystemPalette(themePalette->resolve(defaultPlatte));
-            QApplicationPrivate::initializeWidgetPaletteHash();
-        } else {
-            QApplicationPrivate::setSystemPalette(defaultPlatte);
-        }
+    if (QApplicationPrivate::sys_pal)
+        return; // Already initialized
+
+    QPalette defaultPalette;
+    if (QApplicationPrivate::app_style)
+        defaultPalette = QApplicationPrivate::app_style->standardPalette();
+
+    auto *platformTheme = QGuiApplicationPrivate::platformTheme();
+    if (const QPalette *themePalette = platformTheme ? platformTheme->palette() : nullptr) {
+        QApplicationPrivate::setSystemPalette(themePalette->resolve(defaultPalette));
+        QApplicationPrivate::initializeWidgetPaletteHash();
+    } else {
+        QApplicationPrivate::setSystemPalette(defaultPalette);
     }
 }
 
@@ -379,7 +382,6 @@ QString QApplicationPrivate::styleSheet;           // default application styles
 QPointer<QWidget> QApplicationPrivate::leaveAfterRelease = nullptr;
 
 QPalette *QApplicationPrivate::sys_pal = nullptr;        // default system palette
-QPalette *QApplicationPrivate::set_pal = nullptr;        // default palette set by programmer
 
 QFont *QApplicationPrivate::sys_font = nullptr;        // default system font
 QFont *QApplicationPrivate::set_font = nullptr;        // default font set by programmer
@@ -431,13 +433,6 @@ void QApplicationPrivate::process_cmdline()
     if (styleOverride.isEmpty() && qEnvironmentVariableIsSet("QT_STYLE_OVERRIDE"))
         styleOverride = QString::fromLocal8Bit(qgetenv("QT_STYLE_OVERRIDE"));
 
-    if (!styleOverride.isEmpty()) {
-        if (app_style) {
-            delete app_style;
-            app_style = nullptr;
-        }
-    }
-
     // process platform-indep command line
     if (!qt_is_gui_used || !argc)
         return;
@@ -552,6 +547,12 @@ void QApplicationPrivate::init()
 
     // Must be called before initialize()
     QColormap::initialize();
+    if (sys_pal) {
+        // Now that we have a platform theme we need to reset
+        // the system palette to pick up the theme colors.
+        clearSystemPalette();
+        initSystemPalette();
+    }
     qt_init_tooltip_palette();
     QApplicationPrivate::initializeWidgetFontHash();
 
@@ -597,8 +598,20 @@ void QApplicationPrivate::initialize()
     // needed for widgets in QML
     QAbstractDeclarativeData::setWidgetParent = QWidgetPrivate::setWidgetParentHelper;
 
-    if (application_type != QApplicationPrivate::Tty)
-        (void) QApplication::style();  // trigger creation of application style
+    if (application_type != QApplicationPrivate::Tty) {
+        if (!styleOverride.isEmpty()) {
+            if (auto *style = QStyleFactory::create(styleOverride.toLower())) {
+                QApplication::setStyle(style);
+            } else {
+                qWarning("QApplication: invalid style override '%s' passed, ignoring it.\n"
+                    "\tAvailable styles: %s", qPrintable(styleOverride),
+                    qPrintable(QStyleFactory::keys().join(QLatin1String(", "))));
+            }
+        }
+
+        // Trigger default style if none was set already
+        Q_UNUSED(QApplication::style());
+    }
 #if QT_CONFIG(statemachine)
     // trigger registering of QStateMachine's GUI types
     qRegisterGuiStateMachine();
@@ -789,8 +802,6 @@ QApplication::~QApplication()
     delete QApplicationPrivate::app_pal;
     QApplicationPrivate::app_pal = nullptr;
     clearSystemPalette();
-    delete QApplicationPrivate::set_pal;
-    QApplicationPrivate::set_pal = nullptr;
     app_palettes()->clear();
 
     delete QApplicationPrivate::sys_font;
@@ -1016,55 +1027,45 @@ void QApplication::setStyleSheet(const QString& styleSheet)
 */
 QStyle *QApplication::style()
 {
-    if (QApplicationPrivate::app_style)
-        return QApplicationPrivate::app_style;
-    if (!qobject_cast<QApplication *>(QCoreApplication::instance())) {
-        Q_ASSERT(!"No style available without QApplication!");
-        return nullptr;
-    }
-
     if (!QApplicationPrivate::app_style) {
-        // Compile-time search for default style
-        //
-        QStyle *&app_style = QApplicationPrivate::app_style;
-
-        if (!QApplicationPrivate::styleOverride.isEmpty()) {
-            const QString style = QApplicationPrivate::styleOverride.toLower();
-            app_style = QStyleFactory::create(style);
-            if (Q_UNLIKELY(!app_style)) {
-                qWarning("QApplication: invalid style override passed, ignoring it.\n"
-                "    Available styles: %s", qPrintable(QStyleFactory::keys().join(QLatin1String(", "))));
-            }
+        // Create default style
+        if (!qobject_cast<QApplication *>(QCoreApplication::instance())) {
+            Q_ASSERT(!"No style available without QApplication!");
+            return nullptr;
         }
-        if (!app_style)
-            app_style = QStyleFactory::create(QApplicationPrivate::desktopStyleKey());
 
-        if (!app_style) {
+        auto &defaultStyle = QApplicationPrivate::app_style;
+
+        defaultStyle = QStyleFactory::create(QApplicationPrivate::desktopStyleKey());
+        if (!defaultStyle) {
             const QStringList styles = QStyleFactory::keys();
             for (const auto &style : styles) {
-                if ((app_style = QStyleFactory::create(style)))
+                if ((defaultStyle = QStyleFactory::create(style)))
                     break;
             }
         }
-        if (!app_style) {
+        if (!defaultStyle) {
             Q_ASSERT(!"No styles available!");
             return nullptr;
         }
-    }
-    // take ownership of the style
-    QApplicationPrivate::app_style->setParent(qApp);
 
-    initSystemPalette();
+        // Take ownership of the style
+        defaultStyle->setParent(qApp);
+
+        initSystemPalette();
 
-    if (QApplicationPrivate::set_pal) // repolish set palette with the new style
-        QApplication::setPalette(*QApplicationPrivate::set_pal);
+        if (testAttribute(Qt::AA_SetPalette))
+            defaultStyle->polish(*QGuiApplicationPrivate::app_pal);
 
 #ifndef QT_NO_STYLE_STYLESHEET
-    if (!QApplicationPrivate::styleSheet.isEmpty()) {
-        qApp->setStyleSheet(QApplicationPrivate::styleSheet);
-    } else
+        if (!QApplicationPrivate::styleSheet.isEmpty()) {
+            qApp->setStyleSheet(QApplicationPrivate::styleSheet);
+        } else
 #endif
-        QApplicationPrivate::app_style->polish(qApp);
+        {
+            defaultStyle->polish(qApp);
+        }
+    }
 
     return QApplicationPrivate::app_style;
 }
@@ -1128,17 +1129,21 @@ void QApplication::setStyle(QStyle *style)
     // take care of possible palette requirements of certain gui
     // styles. Do it before polishing the application since the style
     // might call QApplication::setPalette() itself
-    if (QApplicationPrivate::set_pal) {
-        QApplication::setPalette(*QApplicationPrivate::set_pal);
-    } else if (QApplicationPrivate::sys_pal) {
-        clearSystemPalette();
+    if (testAttribute(Qt::AA_SetPalette)) {
+        QApplicationPrivate::app_style->polish(*QGuiApplicationPrivate::app_pal);
+    } else {
+        if (QApplicationPrivate::sys_pal)
+            clearSystemPalette();
         initSystemPalette();
-        QApplicationPrivate::initializeWidgetFontHash();
-    } else if (!QApplicationPrivate::sys_pal) {
-        // Initialize the sys_pal if it hasn't happened yet...
-        QApplicationPrivate::setSystemPalette(QApplicationPrivate::app_style->standardPalette());
     }
 
+    // The default widget font hash is based on the platform theme,
+    // not the style, but the widget fonts could in theory have been
+    // affected by polish of the previous style, without a proper
+    // cleanup in unpolish, so reset it now before polishing the
+    // new style.
+    QApplicationPrivate::initializeWidgetFontHash();
+
     // initialize the application with the new style
     QApplicationPrivate::app_style->polish(qApp);
 
@@ -1389,11 +1394,8 @@ void QApplicationPrivate::setPalette_helper(const QPalette &palette, const char*
         // Send ApplicationPaletteChange to qApp itself, and to the widgets.
         qApp->d_func()->sendApplicationPaletteChange(all, className);
     }
+
     if (!className && (!QApplicationPrivate::sys_pal || !palette.isCopyOf(*QApplicationPrivate::sys_pal))) {
-        if (!QApplicationPrivate::set_pal)
-            QApplicationPrivate::set_pal = new QPalette(palette);
-        else
-            *QApplicationPrivate::set_pal = palette;
         QCoreApplication::setAttribute(Qt::AA_SetPalette);
         emit qGuiApp->paletteChanged(*QGuiApplicationPrivate::app_pal);
     }
@@ -1436,7 +1438,7 @@ void QApplicationPrivate::setSystemPalette(const QPalette &pal)
     else
         *sys_pal = pal;
 
-    if (!QApplicationPrivate::set_pal)
+    if (!testAttribute(Qt::AA_SetPalette))
         QApplication::setPalette(*sys_pal);
 }
 
diff --git a/src/widgets/kernel/qapplication_p.h b/src/widgets/kernel/qapplication_p.h
index 3167bd423f..79d06ed98c 100644
--- a/src/widgets/kernel/qapplication_p.h
+++ b/src/widgets/kernel/qapplication_p.h
@@ -162,7 +162,6 @@ public:
     static QWidgetList *popupWidgets;
     static QStyle *app_style;
     static QPalette *sys_pal;
-    static QPalette *set_pal;
 
 protected:
     void notifyThemeChanged() override;
diff --git a/src/widgets/styles/qstyleoption.cpp b/src/widgets/styles/qstyleoption.cpp
index 1af839c841..5292d971ea 100644
--- a/src/widgets/styles/qstyleoption.cpp
+++ b/src/widgets/styles/qstyleoption.cpp
@@ -1453,7 +1453,7 @@ QStyleOptionTab::QStyleOptionTab(int version)
     \value None A normal tab button.
     \value HasFrame The tab button is positioned on a tab frame
 
-    \sa features
+    \sa QStyleOptionToolBar::features
 */
 
 /*!