Make QPalette::setBrush() check before detaching

Setting the same brush on the same group and role should
not detach nor alter the result of QPalette::isCopyOf().

Task-number: QTBUG-56743
Change-Id: Ic2d0dd757d703b01e8c5d835a8c124b3317653f4
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Andy Shaw <andy.shaw@qt.io>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

1 files changed, 31 insertions, 0 deletions

diff --git a/tests/auto/gui/kernel/qpalette/tst_qpalette.cpp b/tests/auto/gui/kernel/qpalette/tst_qpalette.cpp
index f43e8d8ee6..ca6f677ba6 100644
--- a/tests/auto/gui/kernel/qpalette/tst_qpalette.cpp
+++ b/tests/auto/gui/kernel/qpalette/tst_qpalette.cpp
@@ -39,6 +39,7 @@ private Q_SLOTS:
     void roleValues();
     void copySemantics();
     void moveSemantics();
+    void setBrush();
 };
 
 void tst_QPalette::roleValues_data()
@@ -128,5 +129,35 @@ void tst_QPalette::moveSemantics()
 #endif
 }
 
+void tst_QPalette::setBrush()
+{
+    QPalette p(Qt::red);
+    const QPalette q = p;
+    QVERIFY(q.isCopyOf(p));
+
+    // Setting a different brush will detach
+    p.setBrush(QPalette::Disabled, QPalette::Button, Qt::green);
+    QVERIFY(!q.isCopyOf(p));
+    QVERIFY(q != p);
+
+    // Check we only changed what we said we would
+    for (int i = 0; i < QPalette::NColorGroups; i++)
+        for (int j = 0; j < QPalette::NColorRoles; j++) {
+            const auto g = QPalette::ColorGroup(i);
+            const auto r = QPalette::ColorRole(j);
+            const auto b = p.brush(g, r);
+            if (g == QPalette::Disabled && r == QPalette::Button)
+                QCOMPARE(b, QBrush(Qt::green));
+            else
+                QCOMPARE(b, q.brush(g, r));
+        }
+
+    const QPalette pp = p;
+    QVERIFY(pp.isCopyOf(p));
+    // Setting the same brush won't detach
+    p.setBrush(QPalette::Disabled, QPalette::Button, Qt::green);
+    QVERIFY(pp.isCopyOf(p));
+}
+
 QTEST_MAIN(tst_QPalette)
 #include "tst_qpalette.moc"