QScopedPointer: deprecate swap

Follow up of 612a01be6513894ab1ec5a36b699a2142ba7f35c
(deprecating QSP::take()): for the same reasons, swap()
functions do not belong to QScopedPointer, or they would
allow the pointer to escape:

  QScopedPointer a;
  {
    QScopedPointer b = ~~~;
    qSwap(a, b);
  }
  // b's pointer escaped its scope

Deprecate them as well.

[ChangeLog][QtCore][QScopedPointer] QScopedPointer swapping
functions have been deprecated, as they would allow the
managed pointer to escape the scope. If you need those semantics,
use std::unique_ptr instead.

Change-Id: I2b0938b62f2ef5a3561f61f595a3fb4c505a8f08
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

2 files changed, 21 insertions, 1 deletions

diff --git a/src/corelib/tools/qscopedpointer.cpp b/src/corelib/tools/qscopedpointer.cpp
index 1dd77a22dc..2f9f6f0dd4 100644
--- a/src/corelib/tools/qscopedpointer.cpp
+++ b/src/corelib/tools/qscopedpointer.cpp
@@ -267,6 +267,10 @@ QT_BEGIN_NAMESPACE
 */
 
 /*! \fn template <typename T, typename Cleanup> void QScopedPointer<T, Cleanup>::swap(QScopedPointer<T, Cleanup> &lhs, QScopedPointer<T, Cleanup> &rhs)
+
+    \obsolete Use std::unique_ptr instead; this function may let a pointer
+    escape its scope.
+
     Swaps \a lhs with \a rhs.
  */
 
@@ -333,7 +337,11 @@ QT_BEGIN_NAMESPACE
 */
 
 /*! \fn template <typename T, typename Cleanup> void QScopedArrayPointer<T, Cleanup>::swap(QScopedArrayPointer<T, Cleanup> &other)
-  Swap this pointer with \a other.
+
+    \obsolete Use std::unique_ptr instead; this function may let a pointer
+    escape its scope.
+
+    Swap this pointer with \a other.
  */
 
 QT_END_NAMESPACE
diff --git a/src/corelib/tools/qscopedpointer.h b/src/corelib/tools/qscopedpointer.h
index a4c57aab8a..5c72e7415d 100644
--- a/src/corelib/tools/qscopedpointer.h
+++ b/src/corelib/tools/qscopedpointer.h
@@ -169,10 +169,13 @@ public:
     }
 #endif
 
+#if QT_DEPRECATED_SINCE(6, 2)
+    QT_DEPRECATED_VERSION_X_6_2("Use std::unique_ptr instead of QScopedPointer.")
     void swap(QScopedPointer<T, Cleanup> &other) noexcept
     {
         qSwap(d, other.d);
     }
+#endif
 
     typedef T *pointer;
 
@@ -206,8 +209,11 @@ public:
         return !rhs.isNull();
     }
 
+#if QT_DEPRECATED_SINCE(6, 2)
+    QT_DEPRECATED_VERSION_X_6_2("Use std::unique_ptr instead of QScopedPointer.")
     friend void swap(QScopedPointer<T, Cleanup> &p1, QScopedPointer<T, Cleanup> &p2) noexcept
     { p1.swap(p2); }
+#endif
 
 protected:
     T *d;
@@ -240,8 +246,11 @@ public:
         return this->d[i];
     }
 
+#if QT_DEPRECATED_SINCE(6, 2)
+    QT_DEPRECATED_VERSION_X_6_2("Use std::unique_ptr instead of QScopedArrayPointer.")
     void swap(QScopedArrayPointer &other) noexcept // prevent QScopedPointer <->QScopedArrayPointer swaps
     { QScopedPointer<T, Cleanup>::swap(other); }
+#endif
 
 private:
     explicit inline QScopedArrayPointer(void *)
@@ -259,9 +268,12 @@ private:
     Q_DISABLE_COPY(QScopedArrayPointer)
 };
 
+#if QT_DEPRECATED_SINCE(6, 2)
 template <typename T, typename Cleanup>
+QT_DEPRECATED_VERSION_X_6_2("Use std::unique_ptr instead of QScopedArrayPointer.")
 inline void swap(QScopedArrayPointer<T, Cleanup> &lhs, QScopedArrayPointer<T, Cleanup> &rhs) noexcept
 { lhs.swap(rhs); }
+#endif
 
 QT_END_NAMESPACE