From f6d70650933c5c1e9b238d8aaa06419223908183 Mon Sep 17 00:00:00 2001
From: Christian Ehrlicher <ch.ehrlicher@gmx.de>
Date: Sun, 12 Feb 2023 17:46:01 +0100
Subject: [PATCH] SQL/SQLDatabase: do not copy q within
 QSqlDatabasePrivate::copy()

Copying the QSqlDatabase pointer inside QSqlDatabasePrivate::copy() is
not a good idea since it must point to the owning instance and not
another one. Since it's not used anywhere we can safely remove it.

Change-Id: Ie45b594305059afd9b8d8b25d4864dd77769acf7
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
---
 src/sql/kernel/qsqldatabase.cpp | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/src/sql/kernel/qsqldatabase.cpp b/src/sql/kernel/qsqldatabase.cpp
index ac6e945ca38..5a8d27a5d06 100644
--- a/src/sql/kernel/qsqldatabase.cpp
+++ b/src/sql/kernel/qsqldatabase.cpp
@@ -46,9 +46,8 @@ Q_GLOBAL_STATIC(QConnectionDict, dbDict)
 class QSqlDatabasePrivate
 {
 public:
-    QSqlDatabasePrivate(QSqlDatabase *d, QSqlDriver *dr = nullptr):
+    QSqlDatabasePrivate(QSqlDriver *dr):
         ref(1),
-        q(d),
         driver(dr),
         port(-1)
     {
@@ -61,7 +60,6 @@ public:
     void disable();
 
     QAtomicInt ref;
-    QSqlDatabase *q;
     QSqlDriver* driver;
     QString dbname;
     QString uname;
@@ -84,7 +82,6 @@ public:
 
 QSqlDatabasePrivate::QSqlDatabasePrivate(const QSqlDatabasePrivate &other) : ref(1)
 {
-    q = other.q;
     dbname = other.dbname;
     uname = other.uname;
     pword = other.pword;
@@ -140,7 +137,7 @@ DriverDict &QSqlDatabasePrivate::driverDict()
 QSqlDatabasePrivate *QSqlDatabasePrivate::shared_null()
 {
     static QSqlNullDriver dr;
-    static QSqlDatabasePrivate n(nullptr, &dr);
+    static QSqlDatabasePrivate n(&dr);
     return &n;
 }
 
@@ -212,7 +209,6 @@ QSqlDatabase QSqlDatabasePrivate::database(const QString& name, bool open)
 */
 void QSqlDatabasePrivate::copy(const QSqlDatabasePrivate *other)
 {
-    q = other->q;
     dbname = other->dbname;
     uname = other->uname;
     pword = other->pword;
@@ -587,8 +583,8 @@ QStringList QSqlDatabase::connectionNames()
 */
 
 QSqlDatabase::QSqlDatabase(const QString &type)
+   : d(new QSqlDatabasePrivate(nullptr))
 {
-    d = new QSqlDatabasePrivate(this);
     d->init(type);
 }
 
@@ -599,8 +595,8 @@ QSqlDatabase::QSqlDatabase(const QString &type)
 */
 
 QSqlDatabase::QSqlDatabase(QSqlDriver *driver)
+    : d(new QSqlDatabasePrivate(driver))
 {
-    d = new QSqlDatabasePrivate(this, driver);
 }
 
 /*!
@@ -609,8 +605,8 @@ QSqlDatabase::QSqlDatabase(QSqlDriver *driver)
     objects.
 */
 QSqlDatabase::QSqlDatabase()
+    : d(QSqlDatabasePrivate::shared_null())
 {
-    d = QSqlDatabasePrivate::shared_null();
     d->ref.ref();
 }